Computation of Fatigue Safety Factors for High-Pressure Die Cast (HPDC) Aluminum Components Taking into Account the Pore Size Distribution

Aluminum high-pressure die casting (HPDC) is used to reduce the cost and weight of various components in the automotive industry. The main problem with HPDC components is related to inherent flaws (porosity, oxide skins, etc.) that are difficult to avoid.

The fatigue of aluminum HPDC parts is typically calculated using two S–N curves; one accounts for flaws in the bulk material and the other for the pore-free surface layer. This does not provide an accurate estimate for computation of the lifetime or safety against failure of the component.

This paper presents a unique way to compute the fatigue safety factor taking into account the pore distribution of the component. The material model used is the so-called Kitagawa-Haigh diagram.

The pore model provides a statistical distribution of pores within a defined region in the component. Multiple runs with a defined random pore distribution are used to compute the fatigue safety factor utilizing the statistical pore distribution of the pore model proposed here for different regions in the component.