Modeling of Distortion during Casting and Machining of Aluminum Engine Blocks With Cast-in Gray Iron Liners
Abstract
A method for quantifying distortions arising in engine blocks of aluminum with liners of gray iron has been developed based on virtual finite element-based simulation tools. The key processing steps comprise the convection cooling step, associated with shrinkage and residual stress build-up, and the machining step. The engine block has been modeled using the finite element method and machining has been simulated using the element-removal technique. The mechanical behavior of aluminum has been characterized by tensile tests at different temperatures and strain rates. The results were used for calibration of a material model capturing the viscoplastic behavior at higher temperatures. Finally, to illustrate the key process steps, results from a complete process analysis are reported comprising the initial stress build-up during cooling and the initial out-of-roundness and out-of-roundness of the liners after various machining operations.