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  • Bolt pretension in a flange joint can be simulated by

    bolt pretension in a flange joint can be simulated by Joints with a 4 in. Similarly the stiffness of the joint can be represented as A . The direction of the surface deviation will influence as well. Dec 10 2013 API 10 000 psi Raised Face Flange Prior to Bolt Makeup Gap Between Flanges 1 8 inches. The factors considered included bolt preload washer surface bearing size edge nbsp I 39 ll keep things simple and the focus will be analysis of a given joint rather than design . We have designed innovative features to increase the efficiency and speed of use across both these sectors. Our K will be 0. A surface deviation also causes plasticity to occur in both bolt and nut by simply pre loading the joint when part of the pretension is used to close the gap. The stress concentration study in boltedjoints by means of analytical to find the acceleration level at which the flange achieve the ultimate tensile stress. 1 Jan 2007 Stiffness of the conventional joints can be calculated if the new analytical method 39 s factors were neglected. 1 while in shear joints the bolts are loaded predominantly perpendicular to the bolt axis as shown in Fig. To study the influence of high strength bolt pretension on the joint plate the different stress distribution on different pretension on the joint plate was studied 9 . Sep 06 2016 Also use torque bolts with ramped torque amplitudes of 30 60 and 100 torque to assure even joint preload. As a result the efficiency of the torque to pretension conversion is greatly reduced. In addition the rock bolt is susceptible to break at the thread end. The following identifies the main factors that cause bolted flange joints to leak and explains how and why using specially engineered Belleville springs on flanges can prevent flange leaks and reduce fugitive emissions 1. Okay now that you know the types of flanges and facings we can begin to talk about how to design it. 52 55 The bolted joint should be designed in a way that there is no Can I run linear bolt analysis without preload eccentrically loaded joint T flange joint examined through a new analytical model called preload is to induce a compressive stress in the clamped part. The Maxbolt Load Indicating Fastener System continuously measures and displays the amount of tension in a bolt or stud. Table 1 provides the gasket surface rotation angle for the tubesheet and channel flange as the joint is bolted up and the In this case the predominant force applied on the bolt is a tensile force pre tension force clamp force . An internal pressure of 10 bar is assumed. Then the Conventional bolt tightening is based on measuring the torque. Use Body Body gt beam connector to simulate the bolt joint No bolt nut In the example the bolt pretension load 500N will be applied to bolt nbsp in the bolts of the bolted flange joint of the pressure vessel so bolt preload which reduces gasket compression and tends to separate This is called a 39 39 prying load 39 39 such a load can and pre tightening force is simulated with PREST179. The radius of the bolt hole is modified in this analysis to be the same as that of the bolt 8 mm. RESULT Stress analysis in single lap joint with applied different bolt pretension in bolted joint range 1000N The picture show a improperly bolted flange because two bolts are too short and the nuts are not completely on the bolts. Bolt connection FEM Modelling connection preload Gap elements Boundary conditions. INTRODUCTION . A loose metal Lap Joint Flange LJF . A datum plane splits the shank of the bolt. The test results show that the proposed In addition the bolt load variations with time for a pipe flange connection are simulated by finite element method. Assembly model. Typical hole types that can be used are standard extra large and short or long slotted. All numerical simulations are carried out using implicit FEM software package ANSYS. Three full scale BFW active joint specimens were manufactured for field operation tests. As an illustration of the importance of the relative stiffness of the bolt to the joint presented above is a joint diagram for a 39 hard 39 joint a low stiffness bolt with a high Oct 13 2017 These cases are enumerated in the RCSC Specification. The central nodes on the upper and lower surfaces of the cylinder are used as control points for the coupling constraints. Hence the design of flanged joints is very important in ensuring the integrity of motor while functioning. The bolted joint is modeled using CATIA software and im ported in ANSYS WORKBENCH. 27 6 nbsp 1 Pretension is the lifeline of any bolted joint how can it be excluded of the boundary In terms of gap between the flanges or maximum stress Principal stress or Why Ansys mechanical simulation fail with two pretension with same body 29 Mar 2014 I need to apply bolt pretension loads at certain bolting points in a model Long before any FEA code included these pretension elements to simulate bolts we use a thermal load on that beam that would mimic the bolt 39 s load in the joint. In addition we have to study the thermal expansion in the bolts to reduce further loss in heel force. The spline on the axle is increased to a more modern 31 spline with a 1. A symmetrical bolt fasten wedge BFW active joint has been innovatively developed in this paper which overcomes the shortcomings of the traditional steel wedge SW active joint. Oct 9 2014. Preload test shall include both the through bolt joint and tapped bolt joint. As these joints are subjected to higher loads due to internal pressure acting inside the motor chamber an appropriate preload is required to be applied in High strength slip critical bolts are also meshed by 10 node tetrahedral structural solid element SOLID92. 3. the flanges and the head nut of the bolt in which the permanent contact is to be In the FEA simulation it would be unusual to model the full thread nbsp 7 Apr 2008 Simulating the Structural Response of a Preloaded Bolted Joint The flat segment or shell wall welded to a horizontal segment or flange . These tests are conducted in a Skidmore Wilhelm Bolt Tension Calibrator. Same angle between bolt head nut and joint interface. this value is quite common between our vendor specification A490 can also be one of these types . The point of the tutorial was to learn how to do this. Pressurization 13 bar 3. Bolted joints disk drum structure vibration characteristics contact stiffness structure stiffness and Jin 3 where the simulation results of natural fre bolted flange joint. It has a spring constant k and will develop a load based on the stretch of the bolt. Gasket elements INTER195 and a 3 D 8 node linear interface element were used for gasket modelling. surface such as the flange of a channel or an S shape A325 bolts require a washer under the element head or nut being turned to tighten the bolt shown under the nut above right A490 bolts require a washer under both the head and nut AISC amp NISD2000 Washers 7 Grip is the distance frombehind the bolt head to the back of the nut Multiplier that reflects the ratio of the mean installed bolt pretension to the specified minimum bolt pretension T m as described in Section 5. Here clamping force is important because the mounting clips must compress on the lower beam flange with sufficient clamping force so as not to loosen under the effects of Pretension of bolts can be easily applied in the ANSYS Workbench environment. Especially for existing flange joints at running power plants there an exchange Sector model of bolted flange joint has been analysed for pretension alone and combination of pretension and axial load. To study the influence of high strength bolt pretension on the joint plate the In study of assembly performance of a gasket bolted flanged pipe joint using 15 proposed a nonlinear virtual material method based on surface contact stress Different tightening sequences would be carried out by setting different load steps. The contact between the disk and the drum flange represents a nbsp 1 May 2014 include preload bolt tightening intensity of the impact and damping would be to study medium impacts on a bolted connection using a circular fixture with a The simulation and experimental results from both cases are compared using a to surface contact elements between head nut and the flange nbsp 3 Sep 2015 Table 4. This standard procedure can as every calculation procedure only give reliable results if realistic gasket factors are used. It can be Other such shear joints do not employ a preload on the bolt as they allow rotation of the joint about the bolt but use other methods of maintaining bolt joint integrity. restraint provided on the outside and inside of the HSS wall through a bolt head or nut see Figure 1 a can typically be accomplished to the webs or flanges of the HSS with high strength bolts Half bolt section simulated with symmetry Contact interactions with pressure penetration Simulation stages 1. The table above shows this minimum bolt pretension for empirical bolt sizes. Bolt pretensions are applied first generating stresses and deformations in the model. Modelling and calculations of an asymmetrical bolted flange connection at the operational stage are presented. The percentage can vary but this is an adjustment depending on the materials offset yield point. RCRBSJ was founded in 1947 but is now known as the Research Council on Structural Connections RCSC . This way of simulation will take more computa tional time for generating the required preload. To evaluate the effectiveness of this method 1 year stress relaxation measurement was carried out. The test was simulated for the thin walled cylinder structure of aeroengine stator casing. In a properly designed joint the increase in the bolt force is far less than the relaxation of clamp force. The applied pretension of the bolt was simulated using the PRETS179 elements. Bolt pre tension measured bolt force 2. An external load is applied to tend separate the joint. 19 First the initial grid is divided and the natural frequencies of the model are calculated. 4 Effect of Joint Geometry and Number of Faying Surfaces 77 Represented in Fig. Introduction . Performing a Mesh convergence study is a separate activity. The assembly model is created with no gap between washer and flange. Jun 07 2020 And how the stiffness of individual bolt or bolts affect the joint behaviour. INTRODUCTION Torque control method using torque wrench is a widely Most commonly bolted flange joints find used assembly procedure Figure 3 a Single shear lap joint b Symmetric double shear lap joint Fastener joints can be difficult to analyze due to the many parameters and complex phenomena involved in the behavior of the joints such as Ekh Sch n Melin 2005 Ekh Sch n 2006 x Friction x Sliding x Bolt hole deformation x Contact x High local stresses If the connection is near the end of the member or if the HSS is large enough for an access hole to be cut into it then one sided bolting i. The temperature differential is tuned give the correct preload value. Make sure you have enough clearance between flanges else the nbsp A structural analysis model will let you apply loads in a similar way. The stresses of bolts under 2 loading conditions were calculated preload only as well as both preload and hydraulic pressure. A high pretension is introduced at the bolts in order to assure the joint and for alleviating the fatigue on these bolts. A bolt axis is defined along which the preload will act. The joint can be modeled as shown below. The gasket is modeled with C3D20R elements or GK3D18 elements. Nine prestressed joints were prepared and three of them were restressed after 3 and then 6 months after the initial The correct function of a flanged joint in a given construction flanges bolts and with given loads pressure temperature additional forces depends on the following 1 choice of the gasket for the operation environment 2 determination of the gasket stress for assembly conditions and 3 gasket stress in operation i. Solid elements SOLID186 and SOLID187 were used for the discretization of the flanges. Achieving uniform bolt preload is difficult when tightening a pipe flange with a number latter has significant influence in cases of pipe flange connection because bolts are A computer code which can solve the problems previously defined nbsp An approach for simulating the shock propagation was proposed using Bolted flange joints are commonly used in many industries because of their ease of assembly and maintenance failure of these joints can result in costly damage. If this does not occur or can be prevented then the loosening of bolts can be reduced. 4 should be used. Much is made of bolt scatter which will see the achieved preload on an individual bolt within 25 percent of target but on a flange with multiple bolts the usual result is to achieve an Mar 13 2016 OK I will try to be brief and direct The bolt is an elastic member. The additional force applied to the joint members by tightening a bolt can affect the amount of tension on the other previously tightened bolts. Mar 22 2019 The static stress of bolts connecting head cover and stay ring in a pump turbine has been analyzed through ANSYS. and adjoining nut and joint member can be seen here in this simulation nbsp When torque is applied on the bolt head a clamp force is achieved. The constraints are applied to the surfaces of the sheets that are under the direct clamping pressure of the washers. Sep 25 2007 Not only that if we have to be more accurate we have to simulate bolt pretension one by one as all the bolts in sructure are not tightened at the same instant. These springs are used to maintain bolt preload by preventing bolt tension loss due to differential thermal expansion high temperature bolt yield packing and gasket relaxation and vibration. Our wealth of experience is perfectly suited to cope with the wide the nut or bolt head relative to the fastened joint resulting in the relative motion occurring within the threads. Therefore the bolt itself was highly idealized as a pure tensile spring only fixed with a weighted link to the bolt head and nut ring surfaces Shear forces were transferred by a separate spring with shear stiffness only acting like a shear pin The two parts being bolted together can and should have nonlinear contact in between them Elastic interactions occur when multiple bolts are present in a bolted joint. 1 Introduction 74 5. F lubricated 2022 Nm 0. Hence it is very necessary to determine the maximum bolt tension for the design of flanged pipe joint. A G ST profile gasket with steel core is considered to seal the joint. It has two 5 inch flange sections of 0. Bolted Joint Analysis Calculator Abaqus Bolt Preload Tutorial The behaviour of bolted joints depending on the two different approaches of Two different approaches to preloading of the bolts will be presented at the first part of the The pretension is simulated by splitting the bolt body and applying a parts of connection bolt pretension force contact between column flange and nbsp Two primary characteristics in the bolted joint are a pretension and a mating account pretension effect and contact behavior between flanges to be joined. Conventionally due to the absence of specific guideline or code provisions a method similar to the The thickness of the gasket is 2. 1 F n Nominal strength per unit area ksi F u Specified minimum tensile strength per unit area ksi I Moment of inertia of the built up member about the axis of buckling see the But I need help with two little problems. Type 1 bolts are made from alloy steel type 2 is of low Carbon marten site steel and type 3 is of atmospheric corrosion resistant steel. Share Save. The IBC connections were tested with a simulated wheel load located at the mid distance between the steel plate joints. While bolt pre tension introduces heel force internal pressure and external loads reduces it. Note that in the joint shown below there are only 2 parts in the grip however the number of parts is not limited to 2 and each part in the joint would be represented by a spring. Gasket creep 3. analyst can determine how closely he could simulate the bolted joint. 3 8 inch diameter bolt in a large diameter cylindrical casing is used to connect the flange specimens. 11 Jul 2014 A simple eight bolt flange model is used for assessing the different methods. The bolt head bearing surface is assumed to be circular and its radius is 12 mm. Surface to surface contact elements are used to account for varying contact distribution 4 The preload or clamp load has been simulated by means of the application of nodal tensile forces at the end of the bolt stud and nodal compression forces at the exterior face of the nut. At this point a cut perpendicular to the bolt axis is defined. Using the finite element FE model with accurate thread geometry with pretension the thread root stresses contact pressure along the helix and at the nut loaded surface in the circumferential direction have been studied. The force acting in the lubricated bolt can be calculated as. This may include clevis linkages joints that can move and joints that rely on a locking mechanism like lock washers thread adhesives and lock nuts . Finally in the no bolt model just the preload are applied around the flange bolt holes. Solon Belleville Springs Reduce Bolted Joint Failures One of the most common applications for a Belleville spring is a bolted joint. Flange steel S355 Material model Linear elastic Yield strength 295 MPa The bolt holes have a diameter of 20 mm. com Pretension can generally be modeled with temperature constraint equations or initial strains. 5 Oct 2016 I will try to answer shortly. While executing this is preferred on all bolted joints it can be more critical on some large joints where the assembly can get cocked or easily have large preload scatter such as on tapered hub type designs. Slip Critical Connections bolt is stretched. Each method joints. Nevertheless the effect of pretension force on the tension stiffness coefficient of bolt defined in EC3 was not considered. Under the initial preloading the bolt carries a tensile load while the flanges carry an equal compressive load. Aug 26 2016 clamp force in the bolted joint during assembly is essential for bolted joint integrity. RESULTS Bolted joint is made up of ISO metric M10 bolt and two flanges with thickness of 30 mm. 3D surface to surface contact elements were employed to model the component method can be used to predict the mechanical behavior of steel joints or composite joints 1 . 2 Example of Bolted Flange Joint loaded with pretension I. integrated through bolted flange joints. If the preload is the appropriate the loading that undergoes the bolt joint is preload percentage of the external load. The stretch creates strain which then produce tensile stress in the bolt. The varied connection parameters shown in Table 1 included the number of bolts on the angle legs bolted to the column flange n b bolt diameter d b angle leg thickness t L configuration eccentricity with respect to the beam centerline and gap between the beam flange and the column flange. This is due to the equipment required for tensioning the bolts and the equipment or devices needed to measure and verify the pretension force. In the first phase bolt preload is performed applying a temperature decrement in the bolt as well as to demonstrate which is the FE model type which can simulate the nbsp 25 Nov 2014 Design have cautions about utilizing a bolted flanged joint at high temperatures. Nnow let us have a look at the mechanics of why bolts fail if flanges are allowed to separate during operation. The surfaces created by the cut can be shifted towards each other. and or partially relieve the joint. Scope that to the annular face on the top of the flange. The PSMESH command is used to define the pretension sections in the middle of the bolt shanks and generate the pretension elements PRETS17 9 through which the pretension force of the bolts are applied by using the command SLOAD. If the bolts expand a certain amount more than the flange the bolt pre tension may be lost at temperature. During each thermal cycle the bolt load may be reduced. To enable bolt preload elongation and elongation due to applied pressure each bolt and nut contact is set as frictionless contact. the conditions when leakage has to be minimized. 7 . 2. Unless otherwise noted paint is not required on flange surfaces that will be embedded in concrete or inside bolt holes although overspray is permitted on The 5 x 10x1 25 high tensile mm bolts should be enough if tightened to provide an elastic bolt stretch but stretch will be lost if there are too many surfaces in the bolt joint that can not carry the bolt load. The datum plane can usually be defined either via pure geometry or by a group of nodes. 5 segment of the pipe joint and employs second order brick elements with reduced integration C3D20R for the pipe hub flange and bolts. On flanged joints for instance the bolts are tightened in stages using a crossing pattern. The accessory setup includes two shafts of different lengths one short and one long. 1 exists in the contact between the bolt head and flange and in the contact between bolt and nut. modeled as an elastic element the bolt is simulated by a linear spring with bending and extensional resistance and the gasket is modeled by a series of nonlinear compression springs. That is the deflection of the joint under a bolt loading condition When geometry of the bolted joint is an annulus with an OD less than 2 5 x the bolt diameter the joint stiffness can be conveniently calculated using k EA l . The most straightforward would be to split the faces of the flange or Exclude the bolted connection from the Simulation. without damaging the bolt or any of the joint members which can occur when a bolt is overtightened. 03 m 1 40 100 561667 N. 5 flange styles the polyethylene Lap Joint Flange Assembly is a three component device consisting of 1. This method is inaccurate the company claims owing to thread and surface friction which can absorb up to 90 of the torque force. Analytic methods for determining the loads on a given bolt of a joint can be found in Shigley 16 or other mechanical engineering texts. 3 is the basic equation for the finite element discretization and can be nbsp pretension bolted joints using the finite element method ANSYS 5. The first pass is tightened to approximately 30 of the final desired preload. Aug 24 2013 The joint modeled was comprised of two L shaped structures connected together using a single bolt. 2 Definition The RCSC Specification for Structural Joints Using High Strength Bolts addresses this in the Commentary for Section 5. Bolt creep 4 In the pretension sequencing as the bolts are tightened flange effects can cause a neighboring bolt to lose its original pretension. 1 and now i have to define the max preload bolts to assemble the joint i saw several calculations where is showed a pre stress of the bolts of 50 of the allowable stress. As can be observed from a study of the diagram the actual amount of increase in the bolt force is dependent upon the relative stiffness of the bolt to the joint. But if you have a flange where the clamp length can t be too long you can change the design by using more but smaller bolts. d Different versions of software make different meshes which can cause different maximum stress values. Mar 25 2017 I m pretensioning bolts in sequence on cylinder head gasketed joint using pretension manager by creating contact surface in shank portion of bolt and applying PTFORCE on it. Polyethylene flange adapter stub end . Avoid using simulated nonthreaded fasteners place keepers or pretension elements due to lack of rota tion. Strain hardening of the steel should be taken into account when the post yielding behaviour of end plate connections is needed. Feel free to try out pre tension at part level. In order to approve the bolt preload stress they evaluate the ange joint using ve di erent criteria concerning Flange rotation Flange plastic strain Bolt membrane stress Bolt membrane bending stress andPlastic strain in gasket outer flanged pipe joint can be found by taking moment at the center of the pipe which gives the equation for maximum bolt tension as shown in equation 1 Figure 2 Front amp plan view with force distribution of a typical flanged pipe joint with 12 bolts By using this method the maximum tension in a bolt can be determined for various pipe The parts within the grip act as a set of springs in series and the grip and the bolt act as springs in parallel. Stress induced by bolts and pretension results. By far the simplest method a DTI is put on one end of a bolt and tightened until the bumps are compressed enough so that a feeler gage cannot be inserted all around or when the Squirter DTI has squirted out silicone properly. Our task is often to analyse flange joint. In a bearing joint the connected elements are assumed to slip into bearing against the body of the bolt If th jiti di d bijitth ldi tf dth h bi 16 e joint s designed as a bearing joint e load s transferred through bearing whether the bolt is installed snug tight or pretensioned AISC BMA Engineering Inc. Figure 4. The bolt behaves like a spring when the pressure is released the bolt is under tension and attempts to contract creating the required clamping force across the joint. Lap joint flanges can be mainly divided into four types loose plate steel pipe flanges with weld on collar loose plate steel pipe flanges with welding neck collar lap joint flanges with welding neck collar and lap joint flanges with welding neck collar. Tension can cut down on or even eliminate elastic interactions and over compression of gaskets and can also get rid of many of the obstacles torque faces when reaching desired preload. The bonded region can be taken as having a diameter equal to the washer used as shown in the figure. effect. 1 Joint Behavior up to Slip 74 5. Eq. 333 major diameter. In the real world however this rarely happens. friction in the joint 18 Bolted Joint Failure Modes. Flange Bolt Torque Calculator. Four Bolt Fange Simulated Installation Duration Mechanically Fastened Joints amp Bolt Preload Jun 14 2016 High strength bolts have been used to assemble steel structures for over 60 years supported by research conducted by the Research Council on Riveted and Bolted Structural Joints RCRBSJ . Embedment relaxation 2. And the calculation method is more suitable for the stress and deformation analysis of the joint or the connecting system. After the external axial force was applied the predicted maximum bending stress at the top and bottom of the section of interest correlated with the analytically You can choose any of the following items from the database shank and waisted bolt dimensions according to ISO as well as metric standard and fine threads bolt heads in accordance with ISO 4762 ANSI B18. The used flange model can be seen below. All specimens used a simulated span of 9. grip showed a decrease in bolt tension after major slip. The flange surfaces in the main wind direction showed signs of corrosion which most likely originated from the bolts. simulated as a thermal load and the exact preload is ob tained through number of iterations. However the type of hole will govern the strength of the connection. The total bolt tension must be able to constrain the joint assembly against operating pressure surge pressure pipe line axial thermal contraction and pipe bending strain from soil 1 Proofload is the published number that full size headed bolts are tested to. See Torque Force Design Equations webpage and torque chart page for recommended fastener torque and equation data. In this paper a liquid sealant is applied to a flexible flanged bolted joint in order to improve the sealing performance. 2 NOMENCLATURE Oct 01 2008 The pretension force in the bolt and the contact between the end plate and the column which have proven to be difficult to include in finite element analyses are simulated well with the present modelling. 8 bolt. 1. 6 at major slip. 3 Evaluation of Slip Characteristics 75 5. 2 Bolts Subjected to Shear 71 4. Sep 19 2016 Bolted joints are generally made up of the bolt head stud nut and the flange top and bottom as shown in fig. By using this method you not only achieve the correct bolt pretension when installing new bolts but can Bolt Pretension How to apply bolt pretension to a body body beam Inistate stress to beam188 element Command snippet Define bolt geometry and load Calculate initial bolt stress required to result in desired bolt load ie needs to be factored to account for load taken to deform the flange If model contains beam elements A flange spool is a basic type of dismantling joint that connect long pipes with flanges at the ends so that they can be bolted to another pipe with matching flange. Bolts in bearing joints are designed to meet two limit states Yielding which is an inelastic deformation above left Fracture which is a failure of the joint above left The material the bolt bears against is also subject to yielding or fracture if it is undersized for the load above It often happens that an engineer chooses a high grade bolt for a joint that has had bolt failures with a standard 8. As practical examples consider a pipeline flange pressure vessel engine or other application that depends upon bolts to provide sealing pressure for gaskets O rings or simply just holding two or more components together. The bolt therefore must be stretched to be effective as a clamp. The tensile load in the bolt causes friction torque between the bolt and the joint surfaces and between the bolt and the joint threads. Establishing a threaded model can be very troublesome for pre processing and solving. A new method was proposed to calculate the pretension of bolts and introduces methods of checking the strength stress concentration of this kind of coupling. Then the influences of distance between bolts and tube distance between bolts and edge of flanges thickness of flanges bolt number and bolt pretension on bearing capacity of flexible flange are investigated. In 2013 a whole part of the tower top of a wind Tension is the quickest most dependable way to attain an even bolt preload when several bolts have to be tightened on a flange. The link breakage of segment joint in the solid fuel rocket can lead to gas leakage and result in blast due to failure of the O rings. I am expecting that the bolt pretension force will act in compression but when i run the simulation bolt pretension is acting in the opposite direction. Contact between bolt and flange nut and bolt are defined as bonded with asymmetric behaviour. 1 Schematic diagram of Bolted Joint The joint separation becomes critical at tensile loading of flanged bolted joints. e. To nbsp Analysis of Bolted Connections in Creo Simulate. The bolt is stressed up to the proofload value and if there is no deformation elongation or fracture then the bolt is deemed to have passed. 1 Figure 1 Tensile joint Figure 2 shear joint 1009 Feb 22 2015 They developed a simplified nonlinear model with bilinear springs to model the bolted flange joints in cylindrical pipe structures. Section 3 BoLteD FLAnGe JointS Piping systems can be extremely complicated and a plant can have several When tightening the flange bolts using a torque wrench or other not accurately simulate most real world applications. 3 Numerical FE model The axisymmetric arrangement of the simulated flange with an SMA stud in the center lends itself well to a 1 dimensional analysis which can be treated analytically without great difficulties. A typical pretension connection for an underhung loft block has the block mounting clips holding the block assembly onto the beam flange placing the fasteners in tension. If you are interested in further detailed analysis of your bolts you may want to include the details of the 4. The metal Lap Joint Flange LJF cross section geometry may be a rectangular solid or a contoured cross section. To minimize this primary characteristics in the bolted joint are a pretension and a mating nbsp 17 Feb 2018 The thesis is about how computer simulation tools can be combined with VDI 2230 a calculation analysis of bolted joints according to the guideline VDI 2230. BS 3580 gives useful guidance on the different factors affecting the fatigue resistance of V shaped screw threads. approaches for modeling the bolt pretension i. 27 Jan 2015 A Bolt can connect two components multiple components or a component and the ground. The 3D flow of the pump turbine was simulated to get the pressure on head cover and stay ring. 7 8 studied the assembly process of pipe flange bolt connection by finite element simulation calculation. Abstract. Ansys Bolt Connection Aug 27 2016 difficulty of ensuring that all bolts are adequately pre loaded In double cover connections small differences in ply thickness in plates of nominally the same thickness can result in the preload from bolts near the centre of joint being applied to the wrong side of the joint. Bolted joints have been simulated using finite element method in the literature 13 14 . The 3D finite element model was established in Ansys. This means that the joint may not be as strong as it should be. E b b k 10 b L b 2 A D 11 b 4 where A is the effective stress area of the bolt E is Young s modulus of bolt material L is the effective b b b length of the bolt and D is the nominal diameter of the bolt. The load can be obtained from either analytic models or finite element analyses. 18 Oct 2010 If not can I run the FEA on the structure as a welded frame amp get loadings at the connection points. Nov 03 2010 Part II for FEA of bolted flange with Gasket using APDL APDL MAcro. The . 4 should be multiplied by a factor of 0. A detail of both options is given in Figure 5. Joints with oversized holes or slotted holes Joints where welds and bolts sharing in transmitting load Joints in axial tension or combined axial tension and shear Bearing type bolted connections can be designed for joints T bolts are quite common for joining wood and wood agglomerates a transverse cylinder receives the load from the laminate and transfers it to a tension bolt located in a hole done in the plane of the laminate. Bolts. When a load tries to separate a bolted flange joint the job of the bolt is to hold the flanges together nbsp 18 Sep 2018 With respect to the modeling of bolts in a flanged connection various For bolt pretensioning in Abaqus the preload can be applied as a force nbsp 9 Oct 2014 Pretensioned Bolt Analysis of a Flanged Joints with Gasket elements. Make a fixed joint between the vertex of the line body and the circle in the midsurface and repeat for the other midsurface and the other end of the line body. The preload target can be achieved by a variety of methods applying a measured torque to the bolt measuring bolt extension heating to expand the bolt then turning the nut down torquing the bolt to the yield point testing ultrasonically or by applying a certain number of degrees of relative rotation of the threaded components. The analysis shows that the reduction of bolt tension resulted in the bolt fatigue failure. But this affects a little negligible into FE Analysis Results. The bonded region simulates friction grip of the joint around the bolted connection. Bolts that lost the required pretension are retightened. Bolt Model 5 Geometry is same as Bolt Model 4 Bolt thread contact between bolt and nut is replaced by a cylindrical joint APDL command is inserted to redefine joint as a crew joint Contact between bolt and flange as bonded with asymmetric behaviour. a bolted flange connection design tool that can reduce the engine be conducted including the nonlinear effects in order to simulate the deformation. Finite element models are normally created to simulate the bolt joint using contact analysis. Application Notes The longer the bolts the less sensitive they are to relaxing due to compression of the contacting surfaces in the joint. 8 mm and 10. Bolt preload in joints Welding sequence of flange circular seam. In this method the panel zone is appropriately simulated by a combination of mechanical components and a mechanical model can be established by the use of linear or non linear springs which are based on the mechanical components properties. Simulation took about one minute with a dual core processor. The bolt set. One step further any bolt is never tightened fully at a single stage Ex Flange Bolts . In the experiment the crack is simulated by an asymmetric flange joint. High preload tension helps to keep bolts tight A bonded connection is created around the bolt hole as shown. 3 Bolts Subjected to Combined Tension and Shear 71 5. Jan 11 2018 The rules are intended to provide bolts with sufficient pre tension to achieve two objectives 1 Counter a pressure induced force W m1 which tends to pry open the flange in operation and 2 provide a compressive force W m2 which is needed to seat the gasket during initial assembly of the flange joint. The problem is maintaining this preload through the life of the joint. Using the finite element FE model with accurate thread geometry with pretension the thread root stresses contact pressure along the bolt thread helix between flanges on bolt head and at the nut loaded Sep 18 2018 Pretension Options. Based onASME B16. However in order to model more Pretensioned joints are allowed to resist shear by shear bearing bolt pretension is required due to significant load reversal fatigue with no reversal load of the loading direction A325 or A490 bolts subject to tensile fatigue and or A490 bolts subject to tension or combined shear and tension. For bolting specifications that do not have a published proofload it is usually calculated at 92 of minimum yield strength. There are different approaches for modeling the bolt and pre stressed bolted joint connections in FE analyzes. Meshed model of bolted joint Figure 5. A beam connection of a bolted preloaded joint is an efficient way to accurately transfer loads between flanges. The larger joints can also mean more potential for interfering with other elements such as mechanical and archi tectural components. 60 times the minimum bolt Ratio flange to bolt stiffness total joint stiffness Description Force Results Maximum allowable force on a bolt Total force that can be applied to joint till joint preload is l Force added to each bolt preload force by Fleak Total force on a bolt when the joint starts to leak Force on joint at which bolts break Preload stress in a bolt based Dec 09 2015 Bolt preload is simulated using PRETS179 element in ANSYS which can be used on solid or line element types. joints e. 85. Painting of Bolt Holes con t 3. force on bolt and nut force on bolt nbsp Then the relationship between the tightening torque and ity of the influence on the structural natural frequencies can be summarized as a Keywords. In the past investigation the axial preload of bolt was simulated by applying bolt load on a section of bolt 8 10 16 18 . Then nbsp Keywords Numerical simulation Bolted flange connection Bolt tension Shigley 39 s and contact element modeling the pretension of bolt joints the solid bolt can. The typical polyethylene flange adapter with loose LJF is also known as a Van Stone Flange joint. 1. 28 Jul 2020 the decay rate of the preload in the bolted joint is positively correlated with the The model can be applied to analyze the loosening rule of bolted structures endowed with bolted flange joints by using measured modal parameters. 2 which is a typical coefficient of friction without lubrication . With different loading conditions especially high loads bolted connections can separate which can be minimized by the application of a pretension to the bolt. Feb 07 2017 Joints Using High Strength Bolts August 1 2014 could effect the bolt pretension for tension flange surfaces and inside bolt Oct 08 2020 Assemble and tighten the nut and bolt to the recommended lubricated torque value using a calibrated torque wrench. The force applied to each bolt is de ned as FB. The next two passes would For flanged joints with the gasket floating between the flange faces there is a European standard calculation procedure under construction prEN 1591 3 that allows a tightness analysis as well as a stress analysis. This is way above what the bolt can handle and fatal failure is likely. For bolts with cut threads where the threads do not comply with EN 1090 the relevant values from Table 3. Flange model. This fastener bolt torque calculator will Estimate the unknown torque diameter axial force applied and coefficient of turning friction for the given conditions. However the contact model requires prior experience for defining the contact pairs and proper parameterscalculation such as contact stiffness friction etc. bolt tension at pipe joints. In dependence of the desired results and their accuracy the bolt can be modeled as one dimensional beam element a solid body or the combination of both 15 . The stretching results in bolt tension known as preload which is the force that holds a joint together. welded to the bottom flange and flanges coped away to fit the extra bolt. 656 inch thick material. pre tensions for ANSI B16. 13 Aug 2018 The results predicted by finite element simulation are validated analytically RELATED WORK The presence of bolted joints in any structure will will be a function of number of bolts as well as the pre tension effect unveiled by each bolt. PTFE gaskets in industrial flanges the SMA stud retains much higher loads than the steel bolt. 3. Figure 1. Now after round one of applying PTFORCE on all bolts again for round 2 i want to apply PTFORCE . I mentioned that using a Compression Only support could add some fidelity to the joint based model by replacing the joint to ground. The lap joint flange can be rotated which can be useful when fixing issues with bolt hole alignment. Ultrasonic measurement of fastener elongation on both new and existing bolts has proven to be a very accurate reliable and cost effective solution. Sep 06 2016 The predicted contact stress at the bolt joint interface after bolt pretension was simulated correlated with the analytically calculated surface pressure to within 13. Assume a bolt is used to clamp a joint to a set preload value and the bolt has a low stiffness and the joint has a very high stiffness. Tension type joints For joints in which the only force is an applied tensile force in the direction of the bolt axes the tensile force on any bolt should not exceed 0. Consequently the nonlinear relation between the bolt pre tension force and nominal force is evaluated. if the surface quality is bad like machining marks paint too many washers especially spring washers the combined thickness of Based on ASME B16. 2 Basic Slip Resistance 74 5. It is not possible to use same contact surface for 2nd round . Shear capacity of each bolt is twice that of the same diameter in a lap joint. 4. 25. Today bolts are pre tensioned for the highest expected load. There is a non linear segment in the initial stage of the angular preload curve. Sep 12 2018 One way of improving bolt elastically is to have long clamp length. Temperature pretension is generated by assigning different temperatures and material properties to the bolt and the flange. This kit replaces the wheel flange axle universal joint flange and the 4 bolt u joint flange on the tubular rear axle drive shaft. 26 Sep 2013 Simulating bolt pretension prior to computing tensile stress is an important With COMSOL Multiphysics the effects of prestressing a bolt can be easily Since the bolt head is tight against the washer or flange 39 s surface nbsp emergent bolt preload can be understood if summarizing the zones of tightening process. Combined Shear and Tension Applied tension in a slip critical joint is handled dif ferently than in a bearing type joint as discussed in the Fukuoka et al. In the inelastic nonlinear analysis the bolt pretension force is simulated by applying compressive forces on the annular area of the bolt head nut. 4K views. The cause of the fatigue in the bolts was that the pre tension force in the joint was too low. Mounting flange 106 of joint 1 can be bolted at its shoulder 115 to the joint 2 shown in FIG. The terms n and amp phiv represent the effectiveness of the joint in reducing the amount of external loading transferred to the bolt. Different limitations of simulating the joint connections were studied in Yielding happened at both bolt and flange c Failure of the bolt Piluso The Frustum Stress Distribution Form at the Preload. The picture show a improperly bolted flange because two bolts are too short and the nuts are not completely on the bolts. So in the process of welding it can t appear that inside is valgus. The pretension of bolts was simulated with the pretension element the contact pairs were built to deal with interaction between different sections. In our previous study great increases of hysteretic damping and initial slip resistance of timber joints were attained by applying axial pretension to the steel fasteners. When designing a piping system lap joint flanges should not be considered solely to alleviate poor alignment during construction. Keywords wind turbine FEM analysis bolt joint bolt pretension bolt fatigue. Note BX Style Gasket is Somewhat Oversized by . I. qxftc3aotrr b9jvfifevt6r s4d01lag5wzx4j9 izrzfzzodb5sh4d hle21otzcqji 5p0r5eyllk 8r3mlmc5m1n ibjtzcww5o px53imbwvv7 8a8o99lbyqgrc In such a case the above formulas will not apply so nut turn angle would have to be determined empirically using a simulated joint and a tension measuring device as a standard. Defining joints is one of the most difficult aspects when simulating the behaviour of machine tools because there are many variables that can affect the joint s properties. 4 and specifically to the tubular housing 211 of the joint 2. DTI 39 s are individual bolt load cells which measure pretension developed during tightening regardless of torque resistance of the bolt. This develops clamp load in the joint and mimics reality. These are shown in Fig. 6. It can be described by probability distributions. Bolts usually connect two flanges in a pipe joint and are subjected to bending along with axial forces. The preset temperature helps in creating the thermal shrinkage effect in the bolt. Flanges are designed so that the entire nut bolt combination holds the forces on the flange. The bolt load variation is chosen to produce the standardized preloads of 185 and 251 KN for 20 and 24 mm respectively. 5 mm. Once all bolts are tightened they are checked to see if they carry the proper pretension. So strength of flexible flanges subjected to axial force is studied by a program of finite element simulation analysis which considered contact nonlinear problem of the bolt and flange. 10. As the codes warn leakage can be an issue in flanged Element Analysis FEA to simulate the creep relaxation process in bolted pre tension tool was used to explicitly model the bolt. Flange model and two bolts mutual model under real Since HSFG bolts under working loads do not rely on resistance from bearing holes larger than usual can be provided to ease erection and take care of lack of fit. May 21 2012 There is a multitude of different flange configurations considering combinations of flange type size class schedule gasket and the results of any comparison will be affected by many other parameters such as pressure temperature and bolt pretension. Torque meter can be used to measure bolt tension. The goal of the analysis is to investigate the tightness of the flange joint over 100 years by taking into account the creep of pipe and gasket. PPI TN 38 2019 Edition 2019 BOLT TORQUE FOR POLYETHYLENE FLANGED JOINTS Introduction Lap Joint Flanges LJF have been used for decades. The same can be done to the beam element that gets bolt pretension. Using a paint marker apply the torque stripe to each nut or bolt. A more complicated joint test set up shown in Fig. Coefficient of Friction Tests for Flange and Shim Plates if not available from other resource. A conventional FE model of a bolted joint could be constructed to include the bolt and clamped members using many elements and possibly simulate preload with initial strain on the elements. That is why in the field there are multiple tightening passes. In the future I 39 ll create a more realistic model of a flange section instead of cylindrical joint For applying bolt pretension select body instead of face . 1 Distribution of Contact Stress For description of the contact stress distribution a Jul 02 2012 The stiffness of the bolt can be calculated using the equation A . Torque must be applied to the hex faces of the bolt to provide rota tion. There is no record of any research done to date on the effect of slotted holes on the performance of either high strength bolts or bolted joints. g. Theory Additional fastener loadings because of thin flanges and. And the coefficient can be improved by daubing lubrication oil on the thread. The model is loaded with a pretension load and the axial working loads on head top flange and nut bottom flange mating surfaces Figure 5 . Generally preload is simulated as a thermal load and the exact preload is obtained through number of iterations. This is probably not necessary. For the contacts elements CONTA174 and TARGE170 were used. Less than 100 Tensioning Not all applications allow for the simultaneous fit of a tensioning device on each bolt in these cases at least two tensioning pressures are applied. relaxation which can be modelled using an equation derived in this thesis. The pretension can be applied to the line body the same as you have already done. Jan 17 2016 Preloaded Bolts High preload tension increases joint strength creates friction between parts to resist shear and improves the fatigue resistance of bolted connections. The finite element especially high loads bolted connections can separate. As a result it is concluded that a good agreements between numerical and experimental results are obtained by using the strain time equation without delayed elasticity strain which occurs in a moment. E c c Contact surface unit between the bolt head and disk disk and drum and nut and drum is set as surface surface contact element with no restriction. cients of thermal expansion of the bolt and joint and or a difference in the temperature between the bolt and joint. To minimize the joint separation a pretension load is applied to the bolt known as bolt preload. k. The surface deviation on the flange results in lower fatigue strength. Each L shaped structure involved a vertical flat segment or shell wall welded to a horizontal segment or flange . 046 inch to Provide a Pressure Energized Seal Upon Bolt Makeup API 10 000 psi Raised Face Flange After Bolt Makeup Gap 3 64 inches Not Full Makeup Which Occurs After Pressuring Up Which Results in No Gap After grout reached its specified strength the girder system was loaded concentrically at the joint using simulated wheel load distributed over an area of 10 10 in. of bolted flange joint has been analysed for pretension alone and combination of pretension and axial load. A snug Ansys Bolt Pretension Bolts are normally tightened by applying torque to the head or nut which causes bolt to stretch. When the first bolt is tightened the flange near the bolt is compressed. Now that I see the image I can add that the joint was providing 6 DOF to support the model. The rationale for both approaches will become evident. Creep. Figure 2 is an attempt to illustrate the load transfer mechanism involved in a bolted joint by the use of a special fastener. Fig. See full list on hindawi. 5 raised face anged joints with spiral wound gaskets using FE analysis. 5 mm . Since the bolt head is tight against the washer or flange s surface turning the bolt farther causes it to elongate slightly. Joints subject to fatigue loading or significant load reversal. T torque Nm lb f ft K constant. UHDWHU H SDQVLRQ LQ WKH IODQJH This phenomena can be avoided if all of the bolts in a joint are tightened simultaneously. single bolt of a bolted joint once the axial and shear loads on it are known. of a bolted flanged joint. load in the bolt and its representative curve will be simulated by a part of hyperbolic nbsp 28 Jun 2018 the models have high levels of accuracy and can be employed flange plate bolted connection behavior observed in the tests performed at Kumamoto University In the modeling using pretension section adds to the bolt. APPENDIX B Tightening Torque Template for Non Critical Bolts C 2b Calculations for Blind Flange with Analytic VDI 2230 Procedure. The value of penetration is small enough. Symmetric Butt Splices 74 5. Creep 100 years 11 Flange rotation was determined to be the limiting condition for the hydrotest leak problem. Our bolt s diameter will be 0. strength structural bolts in both friction type and bearing type joints. Each bolt flange head is bonded to the assembly hatch flange. Picture of pretension results contour amp table Stresses induced by bolts and pretension results. This Corvette Rear Axle Kit is for the C2 and C3 Circa 1963 1982 Corvettes that originally have 17 spline axles. element simulation analysis slightly insufficient in practical applications. The HDPE flanged joint assembly is an engineered pressure containment connection subject to diverse forces. This calculator can be used to calculate the force acting in a bolt. Contact pressure at the bolt head for pretensioned state and under real loading conditions. Fatigue cracking can be prevented by an adequate pretension of the bolt during initial tightening so that the major part of the fluctuating load is transmitted through the mating parts and not through the bolt itself. Figure 2 FEM models of bolts Finite element models have been created in Ansys software 17 and all the proposed models take into account pretension effect and contact behavior between In this work a flange joint is simulated by using an axisymmetric model for quick results. snug tightened. The system offers a simple method for accurate joint assembly and is the only product available for most applications which will continually monitor clamping force while the fastener is in service. Bolts are tightened to the same minimum induced tension in both types of joint. In this model there is not any contact between bolt and flange. Bonded Connection. paper adopted the solid bolt model to establish the contact unit on the horizontal contact surface of the upper and lower flanges the bolt head an d the contact surface of the nut and the flange which can transmit the tensile bending and thermal loads. It is normal not to know the exact preload force of the bolt. A hanger is shown connected to the bottom flange of a girder. 1 m Sep 26 2013 Bolts are pretensioned by tightening them until they are snug then using a wrench to further torque the bolt. 1 If pretensioned bolts are used in a joint that loads the bolts in tension the question arises as to whether the pretension and the applied tension are additive. Using suitable analysis software this change can be registered and inspection of the machine organised in good time. With Loctite the nuts will stay even if the pretension is lost but the torque can no longer the transferred by tirque. Then create a pre tension in the bolt by adding a force to each half of the bolt on nbsp . The flange resists the hydraulic end force from the channel and rotates in torsion as the end force is transmitted to the bolts. The behavior and life of the joint depends on how tightly the bolts clamp and how long they can maintain Mar 17 2015 Preload also known as clamp load is applied on the fastener and helps to hold the mating flanges together. They compared the performance of this model against dynamic impact loading test data as well as results using a simple beam model of the entire joint and a detailed finite element model of the pipe joint and bolts. The effects of the bolt head and nut are simulated through coupling constraints. Jan 27 2015 SolidWorks Simulation uses a beam element to represent the bolt shank and uses rigid bar elements to connect the beam to the flanges. The pre tension section can also be a group of surfaces for cases where a fastener is composed of several segments. The tightening of the bolt and nut produces a tensile pre stress which is approximately equal to the compressive stress introduced in the joint material. Infact more iterations are required when considering the material nonlinearity of the bolt. The stripe should extend from the nut or bolt head over the washer and to the joint. Meshed The sleeve or Stub end can be the required higher cost alloy but the flange can be the lower cost forged carbon steel. Other such shear joints do not employ a preload on the bolt as they allow rotation of the joint about the bolt but use other methods of maintaining bolt joint integrity. As long as the bolts keep their pretension the nuts will stay in place even without Loctite. So instead of using five bolts you can use ten smaller bolts which will create a more elastic joint says Seow. 8 utilises a stub column bolted between the ends of two equal length half beams. Abstract In this paper the real surface bolt connection model considering the contact characteristics of the joint surface is established by using the finite element simulation method. 5 inches and the axial bolt force will be 11 175 lbs. . Sound pulse generated from one end of a bolt will travel at the speed of sound for the bolt material to the other end of the bolt bounce off that end and return to the generator in a certain period of time. The bolts in a tension joint must act like clamps. The below screen shot shows the deformation after 2 sub steps but it is clearly seen that the two plates are separated because of the bolt pretension. To determine the performance of a bolted joint it is necessary to calculate the joint stiffness. Polyethylene flange adapter FA or stub end. Pretension is applied by a PRETS179 element in the middle of the length of each bolt. bending of flange blades finite bolt distance scatter of bolt load or surface quality of flange face which might influence the actual leak rate significantly. This can be avoided by providing a butt splice joint. INTRODUCTION Nuts and bolts were invented as early as the old civilization. Model boundary conditions 3. Now a days most commercial software packages use pretension ele Fig. variations. Fatigue failure is a result of high load variations and many repetitions. The de formation of bolts nuts and fittings along the bolt axis ais plotted in Fig. Note As with every bolt pretensioning method Turn Of Nut may only be performed after all steel plies in a connection have been drawn into firm contact i. 1992 1994 1996 . It simulates the bolt preload using thermal expansion contraction. Just to remind you we ll follow the ASME BPVC Section VIII Division 1 Appendix 2 ASME Mandatory Appendix 2 Rules for Bolted Flange Connections with Ring Type Gasket in ASME Boiler and Pressure Vessel Section VIII Division 1 Rules for Construction of Pressure Vessels A model can often be of help in understanding why the bolt does not sustain the full effect of the applied load. 18 The pretightening force provided by bolt pretension is used to analyze its free mode. 4 Miscellaneous Surfaces to be painted and the coating system to be used shall be as indicated on plans and or contract documents. Unfortunately the surface treatment on high grade bolts compared with normal electro zinc plated may change the friction conditions which should be taken into consideration when calculating the torque figures. Methods of stress linearization were In the experiment the crack is simulated by an asymmetric flange joint. Usually flange joint with complicate thermal fields non linear gasket many load cases fatigue etc etc. 12 Aug 2019 A flange bolted joint is one of the basic nodes of the pipeline system enabling The geometric model can be constructed on the basis of a 2D To the bolt the pretension load was applied in order to simulate the bolt 39 s force nbsp The flanged joint is modelled and simulation using ANSYS 14 Software. In you were to just tighten a bolt to flush you would have only overcome the friction of The first is a detailed model of a single bolt using solid elements for bolt and flanges while in the second the entire bolted ring flange connection is modeled employing shell elements for the and pretension and ensure that the bolts can develop the necessary pretension without undergoing failure. 6000 Apr 27 2015 The bolts will be in a so called protected condition . Key Words Bolt Bolted Joints Vibration Loosening of bolts. This causes the joint to heat up more than the bolts. However it is difficult to improve the sealing performance of the joints due to the reduction of the interface pressure. Failure to do so will result in inadequate bolt pretension and loose connections. 1 3 represents a 22. Both parameters can be examined by considering the joint as a system of springs as shown in figure 4. A more modern approach uses a dedicated bolt preload option such as shown in Figure 5. The resultant differential thermal expansion DTE results in an increase in bolt load possibly causing the joint components to yield. A double lap bolted joint with a single bolt and nut was considered in the study. Recently bolted joints with flexible flanges have been used from a lightweight viewpoint. For example the connection of two flanges of a pressure vessel constitutes a tensile joint while the connection of a beam to a column can be considered as a shear joint. Variable tightening of the flange bolts produces a temporary gaping of the butt joint which closely approximates to the behaviour of a crack. The joint is at equilibrium with the compressive sealing force distributed across the sealing face and equal in magnitude to the pre tension in the bolts. The pretension load was set as 250 400 and 500 N in the following FE analyses. I am ansys user some years experience with fem fea analysis. Joint failure of steel tube bracing structures usually causes an excavation accident. For bolt pretensioning in Abaqus the preload can be applied as a force or as a reduction in length. . Care must be taken to maintain the calibration of torque and load indicators. They are performed by the bolt manufacturer and MDOT Metals Lab prior to incorporation and are carried out in accordance with ASTM A325. Figure 5 Methods for applying pretension on solid bolt. Mar 12 2019 Almost all the torque wrenches you can buy or rent from us at Ultra Torq are 3 percent. change load to 200N open in load step 2 etc . The bolt pretension force friction coefficient and contact stiffness factor are considered as parameters which are influencing the joint deformation. Shear Bearing Joint. Initial Torque Yield. Therefore in the FE model the clamping load applied by applying a concentrated load which is a self equilibrating force carried across the pre tension section in the bolt shank to the pretension nodes. Part of this load will cause the further extension of the bolt increase in bolt load . 2 0. 27 6. The roles of lap joint flanges Lap joint flanges mainly play the roles of connecting equipment or flanges such as the flanges on the water Jan 22 2018 The initial rotational stiffness of connection was slightly affected by varying the bolt pretension force in a small scale but it was proved that the existence of pretension force itself made a difference. 1 Fig. Flanged joints are being employed in aerospace solid rocket motor hardware for the integration of various systems or subsystems. 4 Simulation Results 4. 2. In China the rock bolt thread encounters the issue of low rolling accuracy which results in coarse thread surface. Initial torque yield is usually due in part to the torquing process. Additionally the joint materials also carry more current than the bolts. Initial torque yield is the initial yield of a bolted joint in which the bolt is in the process of being torqued. The effects of joint geometry They also tested joints that were modified to eliminate web flange tearing failure modes observed in their bolted cleat joint tests Bank et al. High pre tension has a cost and unnecessary pre tension should be avoided. outer the belonging support flange and the bolt Fig. When connect flange the flange should slant at inside but plane at outside and it could give the high strength bolts homologous pretension force. 9 489 views9. However about 90 of this torque will be used just to overcome the friction in the interfaces . soft parts gasket improper tooling and torqueing bolt quality non parallelism of flange joint. If the torque is too low and the flange faces are allowed to separate the bolts lose that protection and see the full cyclic component and usually fail. The mesh for the three dimensional analysis without substructures shown in Figure 1. Bolt installation costs for connections requiring pretensioned bolts will be higher than for snug tight connections. 4. 3 ISO 4014 ISO 4017 ANSI HEX ANSI HEAVY HEX ISO 10642 IFI 536 IFI 538 EN 1665 twelve point flange bolts and nuts in accordance Bolt tensioners are suited to both topside and subsea applications. 5 flange styles the polyethylene Lap Joint Flange Assembly is a three component device consisting of 1. 5 Ultrasonic method. 5 . By that I mean you cannot multi select all your bolt pretensions and change the load and step behavior e. An Example of Calculating Bolt Torque Let s work through a typical example. how external pressure affects the bolt preload all these can be understood with the help of joint diagram. Bolt Force Calculator. So my model is often only section with one bolt for example 1 24 etc. 3 Bolt pretension and axial force values for each analysis set . illustrates the configuration of the preloaded bolted joint. different causes for bolt relaxation and their relation to joint design. For bolts with cut threads such as anchor bolts or tie rods fabricated from round steel bars where the threads comply with EN 1090 the relevant values from Table 3. Based on the software of LMS TEST the experiment of the structure with bolted flange joints was successfully completed for the vibration test analysis and the paper completed the testing under different pre tightening force. Bolt shank diameter 18 mm Pretension load level 80 of Yield strength 720 MPa . The pipe flange has eight bolt holes that are equally spaced in the pitch circle of radius 65 mm. The technology surrounding hydraulic bolt tensioners can either be very simple or extremely complex. bolt is tightened the components of joint contact on tiny spotsthat will be overloaded. A three dimensional 3D finite element model of the joint was generated and then subjected to three different simulated clamping forces followed by different levels of longitudinal tensile load. 5. The bolts in a butt splice joint with two cover plates are in double shear with two shear planes. Surface to surface contacts are defined between the flange connection parts by a pair of contact elements CONTA174 and TARGE170. 7 shows the bolt connection for a hanger. clevis type bracket that was bolted to a rigid wall to simulate bolt pretension Keywords bolted joint machine component design bolt FEA Understandably joint failure can be flange and bolt hole diameters were 20. Mar 17 2014 The second reason you can only make changes to bolt pretension objects one at a time. Jan 31 2017 Noble stresses that with good procedures calibrated equipment and competent personnel torque tightening can be used successfully on most joints. A few high loads will not contribute much. The calculation of the thermal expansion contraction is done automatically by the solver. Applied tension force on the joint is going to partially relax the clamp force while slightly increasing the bolt force. and uses rigid bar elements to connect the beam to the flanges. Test the joint for loosening in simulated or actual service conditions. I have a question regarding bolts preload I calculated a flange according to appendix 2 of Asme VIII div. Mar 25 2017 Fig. The flange joint involves interaction between bolts flange and gasket and it is the most essential part of Pressure vessel Condenser Heat exchanger and Storage tank. Because the compressed parts are being unloaded during the In this study the bending of the flange the extension and bending of the bolts and the non uniform distribution of the gasket compression can all be simulated. The physical model of the joint is based on a flexible flange element that is connected with a rigid support by means of hybrid elements which substitute bolts. Elastic interactions can either increase or decrease bolt preload making it even more difficult to predict. Incorrect pre stressing of bolts on oil and gas flanges cranes and winches could have catastrophic consequences it points out. Nester 14 observed a decrease in bolt tension from o to 8. After the bolts 111 which compress spring 114 are loosened the bearing housing 105 and the parts connected thereto can be lifted off pedestal 9. bolt pretension in a flange joint can be simulated by