Q235钢拉伸过程热塑性效应试验研究及有限元分析  

Experimental research and finite-element analysis of thermoplastic effect during tensile tests of Q235 steel

作　　者：王为清[1] 杨立[1] 范春利[1] 吕事桂[1] 石宏臣[1] 

机构地区：[1]海军工程大学动力工程学院,湖北武汉430033

出　　处：《红外与激光工程》2013年第5期1153-1160,共8页Infrared and Laser Engineering

基　　金：国家自然科学基金(50906099)

摘　　要：在分析材料热弹塑性效应的基础上,用红外热像仪对Q235钢试件在拉伸过程中的表面温度进行测量,获得了不同应变率条件下试件表面温度分布及随时间的变化;确定了Q235钢全程拉伸真应力-真应变曲线,以此作为材料本构关系对拉伸过程中的热塑性效应进行数值模拟,讨论了应变率、η系数、对流换热系数等对试件表面温度的影响。结果表明,应变率越大,变形过程中的热损失越小,从而由塑性变形产生的温升也越高;由拉伸过程中颈缩区域的温升最高、颈缩区域向试件两端温升逐渐降低的分布特点,则可说明在同一时间内塑性变形越大、越集中的区域,其温升也越大。文中的数值计算结果表明,用现有的有限元软件对材料热塑性效应进行数值分析不失为一种有效的研究方法。Based on the analysis of thermo-elastic-plastic effect, the surface temperature of Q235 steel during tensile tests was measured by using an infrared camera. Both the surface temperature field and it versus time for different strain rate were obtained. The true stress and true strain curve was determined, and this curve was used as the constitutive equations of Q235 steel. A numerical procedure was devised to model the thermoplastic effect during the tensile tests by using ANSYS software, and the influence of the strain rate, η coefficient and heat-transfer coefficient on the surface temperature were studied. The results show that the heat loss during deformation process will be smaller as the strain rate increase, and the temperature increase on the specimen surface generated by the plastic deformation will be higher. The temperature rise at the middle of specimen near the necking area is maximum, while it declines towards the end of specimen from the necking area. It is concluded that the larger and more concentrative plastic deformation of specimen happens at the same time, the much higher temperature rise can be obtained.The simulation results show that it is a good way to analyse the thermoplastic effect by the commercial finite element software. Smaller as the strain rate increase, and the temperature increase on the specimen surface generated by the plastic deformation will be higher. The temperature rise at the middle of specimen near the necking area was maximum, while it declined towards the end of specimen from the necking area. It is concluded that the larger and more concentrative plastic deformation of specimen happened at the same time, the much higher temperature rise could be obtained. The simulation results matched well with the experiment results showed that it was a good way to analyse the thermoplastic effect by the commercial finite element software.

关 键 词：Q235钢 准静态拉伸 热塑性 应变率 有限元 

分 类 号：TG142[一般工业技术—材料科学与工程] O348[金属学及工艺—金属材料]