关键词:
critical plane
fatigue crack initiation
fatigue life prediction
multiaxial loading path
nonproportional loading
摘要:
The present studies are aimed at validation of a newly developed critical plane model with respect to large variety of engineering materials used for different applications. This newly developed model has been recently reported by present authors. To strengthen general applicability of this model, multiaxial test database consisting of a wide variety of multiaxial loading paths have been considered. The strain paths include pure axial, pure torsion, in-phase axial-torsion, out-of-phase axial-torsion with phase shift angles varying from 30 degrees to 180 degrees having sine/trapezoidal/triangular strain waveforms, with/without mean axial/shear strains and asynchronous axial-torsion strain paths of different frequency ratios etc. The materials covered in present study are mainly categorized as ferrous and nonferrous alloys. In ferrous alloy category, material grades from plain carbon steel (mild steel, 16MnR, SA333 Gr. 6, E235 and E355), low-alloy steel (1Cr-Mo-V and S460 N) and austenitic stainless steel (SS304, SS316L and SS347) have been considered. In nonferrous alloy category, aluminium alloys (2024T3-Al, 7075T651-Al, and PA38-T6-Al), titanium (pure titanium and TC4 alloy), cobalt base super-alloy (Haynes 188), and nickel alloy (Inconel-718) have been considered. The predicted and test fatigue lives are found in good agreement for all these materials and complex multiaxial loading paths.