Goal
Predict HCF fatigue life using Stress-Life (S–N) in Durability, reading stresses from a Static analysis of a press (punch/die) setup.

Environment
3DEXPERIENCE (SIMULIA Structural + fe-safe Durability, EDU license) / Solid elements / Units: MPa, mm

Model & BCs (current)

• Die/Base: bottom face Clamp
• Punch: Applied Translation (Y) on the top face (prescribed displacement)
• Sheet: ideally free (controlled by contact); to avoid drift, only two tiny faces: X=0 at one, Z=0 at another ( Y is free )
• Contacts: punch–sheet and sheet–die with friction

Durability (S–N) settings

• Life regime: Finite life
• Algorithm: von Mises (stress-based)
• Mean stress correction: Goodman ( UTS provided)
• Frequency domain: von Mises / None
• Override material contains S–N curve (R=−1), endurance limit, UTS
• Issue 2 – Warning

• Step 'Static Step1' contains non-linear geometry.
  Fatigue results for solid elements will be incorrect unless material orientations have been defined for those elements.
  

• It appears when Geometric nonlinearity (NLGEOM) is ON in the Static step.
• Q2) With stress-based S–N (signed von Mises), do I still need to define Material Orientation for solid elements when NLGEOM is ON?
  • (a) For elastic HCF, is turning NLGEOM OFF the recommended approach?
  • (b) If NLGEOM is required, where and how should I define the orientation (Cartesian vs Cylindrical) for solids in 3DEXPERIENCE?