The Structural Integrity of Cast Aluminium Automotive Components Subjected to Fatigue Loads

摘要: In moves towards lighter, more energy-efficient vehicles, the automotive industry is showing interest in space-frame aluminium structures for car bodies. One concept design features use of hollow extrusions which slot over suitably shaped cast nodes, will be subjected service to bending stresses and shear stresses. Given presence sensitivity fatigue life defects, particular attention has been paid present research surface defects produced by casting effects polishing or shot-peening as-cast surface. The alloy studied LM25 TF two main processes have employed: sand-casting gravity-die-casting. For sand-castings, significance were found hollows pores, but cracks die-cast material associated mainly with entrained oxide films. Surface machining removes leaves pores films unaffected, S-N curves can derived from a consideration fatigue-crack growth-rate data distributions initial defect size, an allowance initiation contribution. calculations are made on probabilistic basis. paper also discusses results obtained shot-peened material, residual generated, ways these may incorporated into crack-growth models.