Thermal problem conclusion

View a summary of the findings for the temperature dependent problem.

For this problem, the inclusion of thermal residual stresses at the constituent level had a moderate effect on the ultimate load. For different loading types (tension, shear, mixed, etc.), temperature changes, and material properties, the influence of constituent level residual stresses may have a more significant influence on the ultimate load. However, it is evident that the temperature dependent material has an ultimate strength approximately 10% lower than the non-TD material systems.

You can see from this example that using a material system which exhibits more temperature dependence on material properties can have a much different ultimate strength prediction than an analysis ran with properties at room temperature. Therefore, you are cautioned about analyzing structures under large temperature changes. If the temperature changes are large enough to induce significant property changes, you should acquire material properties for the temperature(s) of interest and include them in the Helius PFA job.

Furthermore, the inclusion of thermal residual stresses from cure had a moderate impact on the results of this specific problem. An investigation on ply-level failures incorporating thermal residual stresses has been previously studied in great detail [3] to show a negligible impact. However, if there is concern on their impact on failure calculations for a specific analysis, the *CURE STRESS keyword should be included in the HIN file to incorporate their effects.