Week 8 Worm Gear Challenge
Week 8 Challenge: Worm Gear Challenge
Course: Structural Analysis Using Ansys Workbench
Submitted by: Amanpreet Singh Whan
Supervisor: Vineet G
March 23, 2022
List of Figures
Figure 1- Transient Structural Analysis workflow.
Figure 2- Imported given CAD Model.
Figure 3- Meshed given CAD Model.
Figure 4- Revolute joints created for the highlighted faces.
Figure 5- Joint rotation defined for the highlighted face.
Figure 6- Modified Structural Analysis Settings.
Figure 7- Procedure to be followed to calculate results.
Table of Contents
3.1 Importing and Meshing of CAD Model
1 Introduction
ANSYS is a general-purpose, finite-element modeling package for numerically solving a wide variety of mechanical problems. These problems include static/dynamic, structural analysis, heat transfer, fluid problems, and acoustic and electromagnetic problems. There are two methods to use ANSYS. One method is to use the graphical user interface (GUI). This method follows the conventions of popular Windows and X-Windows-based programs. Another method is to use command files. The command-file approach has a steeper learning curve for many, but it has the advantage that the entire analysis can be described in a small text file, typically in less than 50 lines of commands. This approach enables easy model modifications and minimal file-space requirements. The ANSYS environment contains two windows: the main window and an output window. A large number of files are created when ANSYS simulation is run.
2 Aims
- Simulate the Worm Gear mechanism using appropriate material for the given Model.
- Apply appropriate Boundary Conditions and Joint Loads.
- Lastly, Determine Total Deformation and Maximum Stress results for the performed simulation and compare the results for the same.
3 Methodology and Results
The section describes the different stages that were performed using an engineering tool Ansys Workbench 2022 for the completion of the Week 8 Challenge. These stages can be further broadly sub-categorized into three key steps, importing the CAD model to apply the boundary conditions and finally performing the simulation to obtain the desired results.
3.1 Importing and Meshing of CAD Model
After opening the Ansys Workbench, the first step is to select the Analysis type and then define appropriate material from the Engineering Data options for the given CAD model. Considering the challenge requirements, Transient Structural was selected for the Analysis type while structural steel was selected for the given Worm Gear model. The following figures highlight the analysis system and material card parameters in detail.
After updating the CAD model in the Ansys Workbench, the next step is to generate a good quality mesh. Meshing is a phase where the CAD geometry is discretized to represent the computational domain in which the solver will discover a solution. A refined mesh helps to achieve better results. The mesh was generated using default mesh settings.
3.2 Joints
A joint is a type of connection or junction at which usually two bodies are joined together in a way that restricts some degrees of freedom (DOFS) while leaving others free. One reference is considered the stationary reference for a joint, while the other is considered the mobile or moving reference. The mobile and stationary references of the joint must be on two different bodies. Joints can also be defined as “grounded”. In this case, the joint connects the mobile reference to a fixed location in space. The stationary references are fixed in space, that is they have all DOFs fixed. Properties of a joint are defined as a joint behavior and can be applied to more than one joint. Joint behavior is characterized by the rotational and translational degrees of freedom of the mobile reference of the joint, as fixed or free concerning the stationary one.
The following figures represent the two body-to-ground revolute joints created as per the challenge requirements.
3.3 Boundary Constraints
Boundary conditions are constraints necessary for the solution of a boundary value problem. The Fixed support constraint restricts all the translation degrees of freedom over the assigned entities to be zero. The force boundary condition applies a distributed force to the structure. It can be assigned to any number of faces of a structure. This boundary condition works as surface traction on each element of the assigned topological entity and its value is proportional to each element’s area.
A Joint Load constraint is assigned to fulfill the challenge requirements. The process followed to assign the boundary constraint is presented in the following figure.
3.5 Analysis Settings
The given Worm Gear model was simulated for a total number of 15 steps to determine appropriate total deformation and other stress-strain results. Therefore, the Large Deflection option was turned on to prevent Penetration and Intersection errors. The following figure represents the modifications performed in the analysis settings.
Simulation Results
The desired output cards have to be created to visualize the simulation or results. Total Deformation, Equivalent Elastic Strain, and Equivalent Stress (Von Mises Stress) cards were created using the procedure illustrated in the following picture. It must be noted that the results have to be generated by running the solve command.
Deformation Results:
Strain Results:
Stress Results:
4 Conclusion
The main aim of the Week 8 challenge was to Simulate the Worm Gear movement using appropriate materials for the given Model. From the results, it was found that the maximum total deformation resulting is 14.818 mm. The maximum equivalent strain and maximum equivalnet stress resulting in the given model are 6.778e-03 mm/mm and 1253.4 MPa respectively.