High cycle fatigue approach based on affected depth and considering the secondary dendrite arming spacing (SDAS) effect for a defective A356-T6 alloy

Autor: Anouar Nasr, Maroua Saggar, Chokri Bouraoui, Wannes Hassine
Rok vydání: 2018
Předmět:
Zdroj: The International Journal of Advanced Manufacturing Technology. 98:2579-2589
ISSN: 1433-3015
0268-3768
DOI: 10.1007/s00170-018-2396-9
Popis: This paper presents a novel methodology to predict the high cycle fatigue (HCF) behavior of A356-T6 alloy contains artificial and natural defects with varying secondary dendrite arming spacing (SDAS). Defect was modeled by a semispherical void located at the surface of a specimen submitted to cyclic loading. The kinematic hardening model of Chaboche implanted in Abaqus is used to illustrate the response of a defective material during cyclic loadings. Then, stress distribution around defects was determined for diverse defect sizes and various loadings. It leads to obtain equivalent stress of Crossland, by considering the SDAS value, from the tip of the defect into the specimen bulk. The fatigue limit was determined by the affect depth approach considering the SDAS effect and the defect size. This approach leads to determine Kitagawa-Takahashi diagrams, for a definite SDAS value, of defect material. A good agreement is observed between computed and experimental results. Obtaining Kitagawa-Takahashi diagrams with SDAS values permit the engineer to be engaged in endurance problem to compute the defective fatigue lives in safe and efficient process. Obtained results visibly show that the mean stress has an unfavorable effect on tension fatigue limit. For defect-free material, the SDAS controls the fatigue limit. Such effect is much more significant under torsion loading.
Databáze: OpenAIRE