Papers by Author: Yu Zhong He

Abstract: In this paper, a new concept of combination degree (CBD) is proposed. And the CBD between nylon and insert in the pipe wrench is investigated using ANSYS .Then studied the effects of factors on the CBD, such as load, elastic modulus, friction coefficient and behavior of contact surface between the nylon and the steel insert. The results indicate that as the load increases from500Nm to1500Nm, the CBD declines from4.92mm-1 to 1.23mm-1, which presents the combinative characteristics become worse. However, with the elastic modulus and the friction coefficient increases respectively, the CBD also increases. When the elastic modulus is 8000MPa, its CBD goes up to1.78mm-1. As the friction coefficient ranges from 0.1 to 0.5,the CBD increases from1.56mm-1 to 2.32mm-1.In addition, different behaviors of contact surface between the nylon and the insert have different effects on the CBD. When such behavior of contact surface is bonded, its CBD is the highest, 3.31mm-1, but when such behavior of contact surface is standard which means that if the separation between the nylon and the insert occurs, the normal pressure equals zero. And its CBD is the lowest, 1.78 mm-1.

Abstract: Shrinkage porosity defects occurring in ring groove underside the pin hole of aluminum piston are strongly influenced by the time-varying temperature profiles inside the solidifying casting. By adopting the finite element analysis software PROCAST and combining with production practice, the gating system which has open-cycle ring feeding channel in the bottom of the piston was compared with conventional techniques; the influence of opening angle of ring feeding channel and different process parameters on shrinkage distribution was researched. The results show the gating system with open-cycle ring feeding channel can satisfy progressive solidification and effectively eliminate the shrinkage in ring groove underside piston pin hole, and can greatly reduce the riser size and improve casting yield; the opening angle influences shrinkage distribution and can be adjusted to achieve effective feeding; shrinkage size is influenced by pouring temperature and casting speed which have less effect on shrinkage distribution. The system of ring feeding channel is adopted, the opening angle and process parameters are adjusted, all which can effectively eliminate shrinkage in the bottom of the piston, improve casting yield and process rate.