TY - JOUR

T1 - Effect of Surface Finishing State on Fatigue Strength of Cast Aluminium and Steel Alloys

AU - Oberreiter, Matthias

AU - Horvath, Michael

AU - Stoschka, Michael

AU - Fladischer, Stefan

N1 - Publisher Copyright: © 2023 by the authors.

PY - 2023/6/30

Y1 - 2023/6/30

N2 - The endurance limit of structural mechanical components is affected by the residual stress state, which depends strongly on the manufacturing process. In general, compressive residual stresses tend to result in an increased fatigue strength. Post-manufacturing processes such as shot peening or vibratory finishing may achieve such a compressive residual stress state. But within complex components, manufacturing-process-based imperfections severely limit the fatigue strength. Thus, the interactions of imperfections, residual stress state and material strength are key aspects in fatigue design. In this work, cast steel and aluminium alloys are investigated, each of them in vibratory finished and polished surface condition. A layer-based fatigue assessment concept is extended towards stable effective mean stress state considering the elastic–plastic material behaviour. Murakami’s concept was applied to incorporate the effect of hardness change and residual stress state. Residual stress relaxation is determined by elastic–plastic simulations invoking a combined hardening model. If the effective stress ratio within the local layer-based fatigue strength is evaluated as critical distance value, a sound calculation of fatigue strength can be achieved. Summing up, the layer-based fatigue strength design is extended and features an enhanced understanding of the effective stabilized mean stress state during cyclic loading.

AB - The endurance limit of structural mechanical components is affected by the residual stress state, which depends strongly on the manufacturing process. In general, compressive residual stresses tend to result in an increased fatigue strength. Post-manufacturing processes such as shot peening or vibratory finishing may achieve such a compressive residual stress state. But within complex components, manufacturing-process-based imperfections severely limit the fatigue strength. Thus, the interactions of imperfections, residual stress state and material strength are key aspects in fatigue design. In this work, cast steel and aluminium alloys are investigated, each of them in vibratory finished and polished surface condition. A layer-based fatigue assessment concept is extended towards stable effective mean stress state considering the elastic–plastic material behaviour. Murakami’s concept was applied to incorporate the effect of hardness change and residual stress state. Residual stress relaxation is determined by elastic–plastic simulations invoking a combined hardening model. If the effective stress ratio within the local layer-based fatigue strength is evaluated as critical distance value, a sound calculation of fatigue strength can be achieved. Summing up, the layer-based fatigue strength design is extended and features an enhanced understanding of the effective stabilized mean stress state during cyclic loading.

KW - bulk defects

KW - cast aluminium

KW - cast steel

KW - computed tomography

KW - elastic–plastic behaviour

KW - fatigue assessment

KW - fracture mechanics

KW - residual stress

KW - surface defects

KW - vibratory finishing

UR - http://www.scopus.com/inward/record.url?scp=85164812125&partnerID=8YFLogxK

U2 - 10.3390/ma16134755

DO - 10.3390/ma16134755

M3 - Article

AN - SCOPUS:85164812125

VL - 16.2023

JO - Materials

JF - Materials

SN - 1996-1944

IS - 13

M1 - 4755

ER -