> something as simple as stress analysis. Stress analysis isn’t simple. In aircraft applications, the analysis has to model not only metals, but composite mat

> something as simple as stress analysis. Stress analysis isn’t simple. In aircraft applications, the analysis has to model not only metals, but composite materials that have anisotropic and nonlinear responses, account for acoustic energy distribution and local concentration effects, incorporate static- low- and high-cycle fatigue mechanisms (which differ in the materials imperfections that initiate them and in how the ultimate failures play out), incorporate time varying and differential spatial temperature distributions ranging from -55°C to ~1500°C (hot section, commercial engines) and on and on. It’s not simple. I really like physical testing to validate analytical models of complex physical systems.