In this course, we discussed how the results of stress analysis helps to validate our model setup as well as provide insights about the design. Let’s summarize the key points from each lesson.
Verifying and Validating the Model Setup:
- Verifying and validating the model setup is a critical step in performing an accurate analysis.
- Deformation results can be verified to check if the applied loads and supports are correct, especially to identify common problems like over-constraining the model.
- Verifying the reaction forces is a very useful check, as it helps us to get an idea about the global equilibrium of our model.
- Understanding the load path helps us to validate whether our simulation model is capturing the actual or expected load path in our system.
- Stress and deformation values can be verified to check if they satisfy our initial assumptions.
- Check for any error messages and warnings that highlight important items that need to be addressed or considered.
Understanding which Stress Measure to Use:
- Stresses are important results used to determine whether a material has failed against the applied load by comparing it with the material strength limit.
- The safety factor is a very useful tool for evaluating the design against yielding and ultimate failure criteria.
- Stress measures should be chosen based on the types of materials and expected mode of deformation (compressive or tensile)
- Maximum Equivalent Stress (von Mises) and maximum shear stress (Tresca) isused to predict yielding in ductile materials, which can include many engineering metals and some plastics.
- Maximum tensile stress and the Mohr-Coulomb theory are used to predict fracture in brittle materials such as glass, cast iron, concrete, and so on.
Analyzing more than One Design:
- Ansys Workbench allows us to create multiple design points and perform what-if analyses to see how outputs depend on input parameters.
- Input parameters define the geometry and boundary conditions while output parameters are typically the results of the analysis.
- The design points can be compared with the help of Parameter Chart and Parameter Parallel Chart.
- Understanding the relationship of input and output parameters allows engineers to select the optimal design. This technique is also used in the automated optimization and sensitivity analysis tools available in Workbench.