Modelling and Analysis of Clevis Assembly under Tensile Test using Ansys

1 Executive Summary The reports shows the results of amodelled clevis assembly under tensile test of aaxial load ad afixed support. The set up and analysis are carried out in Ansys software. The highest strain and stresses are obtained around the contact regions of the assembly while the largest displacement is experienced around the loaded further element from the fixed end. The stress experienced on the pin exceeds the ultimate tensile strength of Stainless Steel, there concluded to have asmall diameter that expected in relation to the loaded parameters. 2 Contents 1 Introduction ......................................................................................................................... 4 2 Modelling strategy and model construction ....................................................................... 5 3 Results, Verification and Validation ................................................................................... 10 3.1 Meshing ........................................................................................................................ 10 3.2 The analysis setting. .................................................................................................. 10 4 Analysis and results discussion .......................................................................................... 13 4.1 The equivalent strain .................................................................................................. 13 4.2 The equivalent stress ................................................................................................. 14 4.3 The total deformation ................................................................................................. 16 5 Conclusions ........................................................................................................................ 18 References ..................................................................................................................................... 19 3 LIST OF FIGURES Figure 1 Clevis Assembly as modelled in Solidworks software ............................................ 5 Figure 2(a) and (b) showing the mechanical properties of Aluminium Alloy and Stainless Steel as used in tensile analysis ................................................................................................. 6 Figure 3 Contact between the Stud and the Pin ...................................................................... 7 Figure 4 Contact between the Clevis and the Pin ................................................................. 8 Figure 5 Contact between the Clevis and the attachment ..................................................... 9 Figure 6 The meshing Result .................................................................................................... 10 Figure 7 The force component showing the applied direction ............................................ 11 Figure 8 The fixed support showing the applied face on the component .......................... 12 Figure 9 Results for the Equivalent Strain .............................................................................. 13 Figure 10 Results for the Equivalent Strain ........................................................................... 15 Figure 11 Results for the Total deformation ........................................................................... 16 4 1 Introduction Clevis pins are used as arapid and secure fastening in place of large machine such as cranes, large rivets and also bolts in large machinery. The clevis whole has an assembly mainly made of parts including the clevis main part, the pin, the stud and the attachment. They are mainly made of an assembly designed with both aflat or domed head on one end and cross-hole at the other, aclevis is put through the holes at the pronged ends of aclevis and is locked in place by acotter pin. [2][3] This paper clearly explains the construction of the clevis in the model concept of It, where ItIs generated using acad software platform called solid works to generate the model graphics as per the drawing of the part model. the Ansys software Is the used to generate the parts as modelled. under the workbench package with he help of the static structural sub section of the Ansys software, the various parts in the clevis assembly Is assigned the material where the clevis part Is assigned the Aluminium Alloy metal while the rest of the attachments are assigned with the Stainless Steel material. the contact between the parts are defined and evaluated. the analysis settings are set to define the loading and the fixed support and the points, the geometry, the magnitude and plane where each of the are applied. The meshing process are set and mesh refinement Is carried out to Improve on the accuracy of the results obtained.[5] the main aim and objective of carrying out this study Is to carry out the static loading to observe the behaviour of the clevis under tensile loading, and Ifany study the magnitudes of these force and loading parameters by obtaining the equivalent stress, equivalent strain and the total displacement of the assembly, their magnitudes, the range graph and also the magnitude plots on the assembly. the results are later analysed ,discussed and aclear conclusion Is obtained. 5 2 Modelling strategy and model construction The model construction of the parts used to make the assembly are obtained by modelling them using the Solidworks software where the actual with accurate geometry models are obtained. The models are obtained by making use of the extrusion, extrusion cut, drilling, threading filleting and accurate dimensioning and the slot cutting procedures to obtain the individual parts. Using the Solidwork assembling tool the parts are assembled using the correct mates such as the concentric, plana parallel mate and the thread mates for the section i.e. in the pin and the clevis which are joined together by threads. The final assembly model of the clevis as generated using the Solidwork modelling toll is as shown in fig 1below as shown in the figure below. Figure 1 Clevis Assembly as modelled in Solidworks software By making the utilization of GEA analysis software ANSYS workbench under the static structural package the modelled part is imported as the geometry as aneutral file format .iges which is a neutral file which is utilized to inter-transfer model between any two CAD software. Using the Ansys package, mechanical the models parts are assigned the materials.[5] Two basic metal materials are defined ,the clevis is assigned an aluminium Alloy metal while the rest of the attachments of the assembly are assigned the Stainless Steel materials. The mechanical properties of these metals selected as the assignation of these parts of the assembly are clearly outlined in the figures below. 6 Mechanical properties of Aluminium Alloy and Stainless steel (a) (b) Figure 2(a) and (b) showing the mechanical properties of Aluminium Alloy and Stainless Steel as used in tensile analysis Since the clevis assembly Is made up of more than one mechanical component there Is a mechanical need and reason to define the contact relations between the parts in the assembly, this Is key in analysing the assembly under the static loading in the static structural tool. there are three types contacts which have been clearly defined in this set up. First the contact between the stud and the pin. the contact Is defined as a concentric mate between the stud as the contact body and the pin as the target body in the 33mm diameters pin and the 33mm drilled holes on the stud component part. Also, a point to note Is that the pin Is mated at an equal distant space on the sides of the stud. the figure below shows this contact definition. 7 Figure 3 Contact between the Stud and the Pin Secondly the contact between the clevis as the contact body and the pin as the target body has also been defined. the contact Is obtained under concentric mate between the 33mm drilled hole on the clevis and the 33mm diameter cylindrical surface of the pin.[5] the pin Is place at a centre point between the side surfaces of the clevis. the figure below shows the figure showing this contact 8 Figure 4 Contact between the Clevis and the Pin The third and the last contact defined under this contact set up Is the contact between the part named attachment as the target body and the underneath counter threaded hole on the clevis which Is defined as the contact body.[5] the contact Is defined as two threaded components with also the help of the concentric nature since both components has been threaded with auniform thread of 33 *2.0 threads. the figure below shows this contact. 9 Figure 5 Contact between the Clevis and the attachment 10 3 Results, Verification and Validation 3.1 Meshing On the mechanical Ansys tool ithas aprovision of meshing abody part(s) .Italso have a Provision of mesh sizing and refinement. the clevis assembly was meshed as abody with the collect mesh sizing on the uncontacted region with ameshes of elements sizes of 5mm.[2] The contacted region between the various parts as discussed above were carried out mesh refinement where these regions were meshed with 2and5 mm mesh sizes for finer meshes on these regions respectively. Both hexagonal and triangular meshing shapes were used to obtain the meshing, the total number of meshing elements obtained is 346757elements and 75779 nodes for the whole clevis assembly. The figure below shows the meshing on the clevis assembly. Figure 6 The meshing Result 3.2 The analysis setting. For each structural analysis there is always a need to define the forces and the loading geometry plane or points where the force act, 11 In the analysis setting ,afixed support plane on the circular cross section plane of the pin part of the clevis assembly have been set as the fixed plane while a Y component force of 50kN on the downward direction is applied on the circular cross section of the part component named attachment. This force and the fixed support settings have been clearly shown the figures below. Figure 7 The force component showing the applied direction 12 Figure 8 The fixed support showing the applied face on the component 13 4 Analysis and results discussion The analysis results of this study are carried out on the concept of understudying the behaviour of the clevis when it is fixed on its top and a tensile loading is applied downwards with a magnitude of 50kilo newtons, the results are discussed on the evaluation of the total deformation, the equivalent stress and the equivalent train of the clevis assembly as shown on the plots. When the mesh refinement is done it aid in increasing the accuracy of the results obtained. Increasing the mesh refinement on the contact region increases the accuracy of the results since these are the most stressed regions. 4.1 The equivalent strain When attempting to explain the state of strain in solids, a scalar number known as the equivalent strain, also known as the von Mises equivalent strain, is frequently utilised. Figure 9 Results for the Equivalent Strain 14 Figure above displays the findings of the in-plane strain measurement. You may infer that there is flawless bonding between these components since the clevis and the pin, as well as the pin and the top attachment, were manufactured to have avery tight fit with one another. This meant that there was no slippage between the two throughout the test. These results to very little strains witnessed on the whole part of the assembly. the region under their contacts experienced the maximum strain despite being minimum of 0.0034042 mm/mm while the lower part of the attachment the list equivalent von mises stresses of 0.0000021013 mm/mm. these values represent very little impact on the physical state of the clevis assembly.[6] 4.2 The equivalent stress Calculating the equivalent von Mises stress involves equating the deviatoric component of the strain energy acquired from peri dynamics and classical continuum mechanics. This is done in order to arrive at the correct value. It is hypothesised that the effective plastic strain can be reduced to the uniaxial plastic strain when the material is subjected to auniaxial stress test.[4] 15 Figure 10 Results for the Equivalent Strain Due to the tendency of slippage and very tight bonding between the clevis and the pin, as well as the pin and the top attachment, which are also manufactured to have avery tight fit with one another there a noticeable increase in the equivalent von mises stresses around this region. Similarly, due to the tendency to bend and resist the fixed support on the upper part of the stud due to the simple swaying of the stud during the downward tensile axial loading the stud around the fixed end experienced highest stresses of 324.41 Mpa for the highest stressed element around the bonded region. This is a very clear evidence that the pin part of the assembly has already failed since it have already exceeded the tensile strength of Stainless Steel (the ultimate tensile strength as previously stated in this study is 250MPa )which the material assigned to this component. Ultimate tensile strength is the stress which upon exceeding the material does not return to its original state. The ultimate tensile strength is already exceeded. Since stress is acomponent of force and the area ,increasing the across sectional area of this 16 component would likely reduce its failure. The diameter of the pin is 33mm which is seen to be below the ideal value for the diameter of this assembly to avoid failing. 4.3 The total deformation The total deformation option allows you to view all of the deformation results associated with your model in three-dimensional space (X, Y, and Z). In the directional deformation mode, you may choose acoordinate (X, Y, or Z) to view the result of the distortion of your physical model in that direction.[4] Figure 11 Results for the Total deformation The end of the stud which Is around the fixed end has the list deformation because Ideally this point Is stationary, there ’re experiencing adeformation of 0mm. the end fthe attachment to the 17 near end where adownward force of 50 kN Is applied experienced the greatest displacement of 2.9617 mm ,this Is due to the relation that Is the furthest element in relation to the fixed support. 18 5 Conclusions It is concluded that there is flawless bonding between these components since the clevis and the pin, as well as the pin and the top attachment, were manufactured to have a very tight fit with one another this resulted to the least equivalent strain on the assembly. The pin of the assembly failure since the stress experienced by the most stresses element exceeded the ultimate tensile strength of the Stainless Steel. Can be concluded that under the set up of a fixed support and a tensile force of 50 kN the pin with a diameter of 33mm cannot withhold, there resulted to the failure, by experiencing astress of 1034 MPa. It is also concluded that the furthermost element in relation to the fixed support and the point where the load is applied experiences the greatest deformation. 19 References [1] T. Thonhauser, Stress and strain in solids: A formalism for the LAPW method. Aachen, Germany: Shaker Verlag, 2001. [2] W. D. Means, Stress and strain: Basic concepts of continuum mechanics for geologists, 1976th ed. New York, NY: Springer, 1976. [3] T. R. Graves-Smith, Stress and Strain. London, England: Chatto & Windus, 1974. [4] “tensile yield strength -Buscar con Google, ”Google.com. [Online]. Available: https://www.google.com/search?q=tensile+yield+strength&rlz=1C1CHBD_enKE766KE7 66&sxsrf=ALiCzsaUKI9fCZynXxfaxyIfIhmCwm0EWw%3A1652642597747&ei=JVOBYt6 QLbiP9u8PurCe6A0&oq=tensile+yield&gs_lcp=Cgdnd3Mtd2l6EAEYAzIKCAAQgAQQh wIQFDIFCAAQgAQyBQgAEIAEMgUIABCRAjIFCAAQgAQyCggAEIAEEIcCEBQyBQgA EIAEMgUIABCABDIFCAAQgAQyBQgAEIAEOgQIABBDOgQILhBDOgsILhCABBCxAx CDAToRCC4QgAQQsQMQgwEQxwEQ0QM6CAgAELEDEIMBOgsIABCABBCxAxCDA ToICAAQgAQQsQM6BQgAELEDOgoILhDHARCvARAnOgQIIxAnOgoIABCxAxCDARB DOgcIABCxAxBDSgQIQRgASgQIRhgAUABY4zhg601oAHABeACAAe4EiAGyMJIBCTIt MS4yLjQuNpgBAKABAcABAQ&sclient=gws-wiz. [Accessed: 15-May-2022]. [5] S. Moaveni, Finite element analysis: Theory and applications with ANSYS: International edition, 2nd ed. Upper Saddle River, NJ: Pearson, 2004. [6] I.Koutromanos, Fundamentals of Finite Element Analysis: Linear Finite Element Analysis, 1st ed. Nashville, TN: John Wiley & Sons, 2018.