Application of FEM to Predict Hardness Distribution of Air-Impact, Compacted Green Sand Molds

摘要

Air-impact molding is one of the modern clay-bonded sand compaction methods. To study the air-impact compaction process, by experiment only, is expensive and time-consuming. Numerical simulation of air-impact molding can provide a useful tool for optimizing pattern plate utilization, improving mold quality and modifying molding machine design. The research presented in this paper is the application of dynamic Finite Element Method (FEM) to simulate the compaction process of molding sand with air-impact molding technology. The constitutive relationship and damping of sand-air mixture under dynamic conditions have been studied. The finite element model has been developed, and it can adequately predict the stress in the green sand mold with a two-dimensional pattern. The functional relationship between compressive stress and mold hardness, as well as mold strength, has been developed experimentally. Hence, the mold hardness readings and the mold strength readings at the mold cavity and the parting line surfaces can be predicted as a function of numerically calculated stresses.