How do you calculate temperature changes in finite element analysis?

1 Why temperature matters

Temperature changes can have a significant impact on the behavior of structures, especially if they are exposed to extreme or variable conditions. Temperature affects the thermal expansion or contraction of materials, which in turn changes their dimensions, stiffness, and strength. This can lead to thermal stresses, strains, and deformations, which may affect the structural performance and stability. Therefore, it is important to consider the temperature changes in your FEA model and how they affect your design criteria and safety factors.

2 How to calculate temperature changes

The first step to calculate temperature changes in FEA is to define the thermal boundary conditions of your model. These are the temperatures or heat fluxes that are applied to the nodes or elements of your model, either as constants or as functions of time, location, or other variables. You can also specify the initial temperature of your model, which is the reference temperature for the thermal analysis. The thermal boundary conditions can be obtained from measurements, estimations, or other sources of data.

The second step is to perform a thermal analysis, which is a type of FEA that solves the heat transfer equation for your model. The thermal analysis calculates the temperature distribution and the heat flow in your model, based on the thermal boundary conditions, the material properties, and the geometry of your model. The thermal analysis can be done as a separate step or as a coupled step with the structural analysis, depending on the complexity and the coupling of your problem.

The third step is to use the temperature distribution from the thermal analysis as an input for the structural analysis. The structural analysis is another type of FEA that solves the equilibrium equation for your model. The structural analysis calculates the stresses, strains, and displacements in your model, based on the applied loads, the material properties, and the geometry of your model. The temperature distribution affects the material properties, such as the thermal expansion coefficient, the modulus of elasticity, and the yield stress, which are usually temperature-dependent. The temperature distribution also generates thermal loads, which are the forces and moments caused by the thermal expansion or contraction of your model.

3 How to apply temperature changes to your design

The final step is to apply the temperature changes to your design and evaluate the results of your FEA. You can compare the stresses, strains, and displacements from the structural analysis with the design criteria and the safety factors for your structure. You can also check the compatibility and continuity of your model with the surrounding structures and the environment. You can use various tools and methods to visualize, analyze, and optimize your FEA results, such as contour plots, graphs, tables, reports, and sensitivity studies.

4 How to avoid common errors and pitfalls

Calculating temperature changes in FEA requires careful attention and verification to avoid common errors and pitfalls. Incorrect thermal boundary conditions can lead to unrealistic temperature distributions and thermal loads, while neglecting the temperature dependence of the material properties can result in inaccurate stresses, strains, and displacements. Additionally, assuming linear or isotropic behavior of the materials may not capture the nonlinear or anisotropic effects of temperature changes on the material properties and structural response. Coarse or incompatible meshes can cause numerical errors or convergence issues in the thermal and structural analyses, while overlooking or misinterpreting the results of the FEA can lead to wrong or unsafe design decisions.

5 How to learn more and improve your skills

Calculating temperature changes in FEA is a complex and challenging topic, but it is also a valuable and rewarding skill for structural engineering. To learn more and improve your skills, you can read books, articles, and manuals on FEA and thermal analysis to gain theoretical and practical knowledge. You can also take courses, workshops, or webinars on these topics for interactive and hands-on learning. Utilizing software, tools, and resources can help with modeling, solving, and post-processing FEA problems. Finally, practicing, experimenting, and exploring with FEA and thermal analysis can enhance your understanding, experience, and creativity.

6 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?