基于有限差分法的铸件凝固过程热应力场数值模拟的研究

Study on Numerical Simulation of Thermal Stresses During Casting's Solidification Process Based on FDM

基于有限差分法(FDM)对铸件凝固过程热应力场进行了三维数值模拟研究,开发了基于微机和Windows平台的通用FDM/FDM铸件热应力场数值模拟原型系统。并采用典型应力框试件和实际铸件对所开发的系统进行了验证,同时进行了浇注试验,并测量了试件的残余应力。结果表明,该系统可以用来模拟铸件残余应力的形成和预测热裂产生的倾向。对铸造应力应变分析与传热分析使用同一FD离散模型,避免了采用不同模型进行热 力耦合分析时的结点匹配问题,减小由此产生的单元温度载荷传递误差;同时使得流动场、温度场、应力场数值模拟统一于差分格式下。

In this paper Finite Difference Method(FDM)has applied for 3D stress/strain calculation of casting and developed a general FDM/FDM numerical simulation prototype system for temperature and stress fields during casting's?solidification process on microcomputer and windows platform.A standard stress frame model and a practical casting were simulated to verify the system.Pouring experiments have been carried out in laboratory.The results of simulation coincided with those obtained from experimentation and practical results.When adopting FDM to calculate casting thermal stresses,thermal analysis and stress analysis can use the same FD model,which can avoid the matching between different models and reduce the errors of temperature load transferring.It makes the simulation of fluidflow fields,temperature fields and stress fields unify into one model.This system takes full advantages of mature FDM technology and can be used to simulate the forming of residual stresses and predict the occurrence of hot tearing.