FINAL REPORT FINITE ELEMENT METHOD CHAIR ANALYSIS CATIA V5 AND ANSYS 18 Presented to Lecture: Dr.Eng. Azhari Sastranegara, B. Eng., M. Eng. Sudent: Ririn Handayani 003201700008 President University December 31st 2019 Abstract Chairs are a tool that we always meet in our activities every day. We will find seat even we will always use the chairs to perform daily activities. The average person uses chairs approximately 2-3 times per day. In the community there are many kinds of chairs ranging from many materials. Now days most people tend to prepare use chair that has enough strength, material that mind is structural steel for applying material in the chair that we analyzed in ANSYS 18, with reference maximum weight 120 kg, safety factor 1 and confortable to use based on 3D design using Catia V5 with price estimation could not over to $100, beside the design with agronomical aspect and drawing of design result simulation of analysis and the model to projection view. Thus this is one of the applications of finite element method in objects in daily life to the chair. Keywords: Finite Element Method, Design, Analysis. Introduction FEM standard for Finite Element Method, the most basic concept of FEM is solving a problem is by dividing the object of analysis into finite small parts. Finite Element is one of the numerical methods that utilize matrix operations to solve physical problems. Another method is the analytical method, which requires a mathematical equation that is a model of physical behavior. The more complex physical behavior (due to the complexity of geometric shapes, the number of load intersections, constrains, material, properties, etc.) the more difficult or even impossible to build a mathematical model that can represent the problem, an alternative method is to divide the case into small simple parts which in this small part we can build a simpler mathematical model. Then the interaction between these small parts is determined based on physical phenomena to be resolved. This method is known as the finite element method, because we divide the problem into a number of specific elements (finite) to represent the problem that the actual number of elements in infinite (Continuum). Analysis Purpose 1. Make a chair design using Catia V5 based on agronomical chair 2. Simulates the state of the chair and it is characteristic with some assumptions. 3. Make an analysis using Ansys 18 of the characteristic of the chair with applied structural steel as a material. 4. To find out the strength of the chair before the actual manufacturing stage and by providing price assumptions. 5. Make drafting of the projection view to find out the point and location of the model made. Research Methodology In doing this analysis, we need to combine the type of application system between Catia V5 and ANSYS 18, where the design and chair modeling stages are carried out in Catia V5 while the analysis and calculation are done at ANSYS 18, so the final results will be presented in this study. However, we can describe the steps taken in conducting research and analysis of the chair that we expect as below. 1. Chair Design using Catia V5. In this case we using part design to make the model of the chair from 2 dimensions, then make workbench to make 3D part. However, the result of design also the part of step model in Catia V5 can show below. Form the figure the chair type that used for hair style seat, then in accordance with aspect of agronomic for hair style seat. Where the plane that we have been applying several plane to made for every part. Moreover, continue to next step for analysis the design that have made it is ANSYS 18. 2. Analysis design use ANSYS 18. To apply the design from other application to ANSYS 18, need to convert system to alter with the analysis part command in ANSYS 18. The way that applied is save as the design for Catia V5 and change the folder type from it is STP file, then it can apply to the ANSYS 18. Furthermore, the step to do the analysis for the chair, firstly we need to know how to operate the command in ANSYS 18. Moreover, the step will describe below. a. ANSYS 18 Command Apply For the first step after apply the design from Catia V5 we need to import the data design that we made, then choose Static Structural and Geometry to import the data and assume some material that we want to apply fro the chair. b. Apply material for ANSYS 18 In this section we need to open the Engineering Data to apply the material for the chair. However, the material that we input is Structural steel based on www.mcmaster.com as a reference for the material, and the material has 1” (inch) has $6.95 then we can apply the material with the base of the chair around 7 part from the material that we used. Then the total is 7x6.24 is $ 43.68 + seat $28 = $71.68 chair price, then we can conclude the price is lower then $100. Furthermore, show the ANSYS system for material apply. The data material that had applied for the analysis chair is become of reference to find the meshing for deformation stress, equivalent elastic and also for the equivalent stress include tool stress for the safety factor to find the result for the chair before applied to the chair before to the reality. c. Model and Static Structural Simulate All the model and static structural aspects of your product. Conduct with linear static analyses that reveal stresses or deformations, modal analyses that determine vibration characteristics, and advanced transient nonlinear studies that focus on dynamic effects and complex behaviors. For the chair analysis cn show for the model result after converting from Catia V5. - Model ANSYS 18 for chair (Geometry Model) After the model checked for the meshing of the chair model. (Mesh of the Model chair) Meshing is defined as the process of dividing the whole component into a number of elements so that whenever the load is applied on the component it distributes the load uniformly called as meshing. - Static Structural Static structural used to make Fixed Support and Force for the object that we analysis. (Fixed Support) Fixed supports can resist vertical and horizontal forces as well as a moment. Since they restrain both rotation and translation, they are also known as rigid supports. This means that a structure only needs one fixed support in order to be stable. (Force) The force that would be needed to cause the bolt to displace to get a loaddisplacement curve from ANSYS 18. d. Solutions for the Chair Analysis - Total Deformation Von Mises However, we can find the total deformation of the chair from the data input from the material input with yield strength 1, 2 pa for the structural steel and young modulus 2E+11 pa to input to the formula. Then the result in ANSYS 18. From the analysis we can obtain the result that we found it is 76555.7 mm or 0,750-4 Mpa, comparing to the yield strength this is more rigid material - Equivalent Von Misses Elastic Strain It is supposed that strain energy w at a per-unit volume is a function of total equivalent strain. Equivalent choices may be made for the expression of a strain field depending on whether in the case of elastic deformation the response function linking strain to the deforming stress is the compliance tensor of the material. Then the formula and result from ANSYS show below. From that figure that we made in ANSYS 18 it will show the Von Misses of the equivalent elastic strain is 3,036 Mpa, then we can see that more than young modulus that we used. - Equivalent Stress Von Misses stress is a value used to determine if a given material will yield or fracture. It is mostly used for ductile materials, such as metals. It same with elastic formula to assume the value. Then calculating and simulate in ANSYS 18. From that figure that we made in ANSYS 18 it will show the Von Misses of the equivalent stress is 55387 Mpa then we can see that more than young modulus that we used. - Tool Stress or Safety Factor In engineering, a factor of safety, also known as safety factor, expresses how much stronger a system is than it needs to be for an intended load. For the reference of FOS (Factor of Safety) From the safety factor reference we can conclude the material of structural steel that we have use is around 4-6. But on that case in ANSYS we see the result is around 0,451357 KN/mm2 then in 4,051357 Mpa. Then is quite near with the reference material factor of safety. Conclusion In the results that have been achieved we can conclude there are some challenges in the results of converting from two different applications where the desired results do not match properly. However, in this convert process the authors continue to strive to provide the best calculation of some formulas used so that the results of the analysis of deformation, strain and stress can be read properly. in this case the safety of this chair reaches 4 where it is adjusted with the FOS reference which is 4-6, but basically this depends on the material used, due to the use of structural steel so the results are so. The use of structural steel material is as an estimated cost of sales for this chair so we get a sales fee of $ 71.68 and this is considered quite cheap because it is under $ 100. This proves the benefits of using analytical design applications on objects that are often encountered in everyday life. APPENDIX