金属厚板力学性能鼓胀试验方法研究

The Mechanical Properties of Thick Plate Steel Based on the Bulge Test

鼓胀试验是一种评定板材力学性能和成形性能的试验方法。由于金属厚板难以直接进行鼓胀试验,提出了一种在金属厚板厚度方向去除部分材料得到试件进行鼓胀试验的方法,将鼓胀试验引入测定金属厚板的力学性能。建立与鼓胀试验对应的有限元模型,将单轴拉伸试验应力应变关系数据作为有限元分析的初始材料本构关系,模拟鼓胀变形过程,得到P-h关系。通过试验获得实际鼓胀过程中鼓胀压力P*、极顶高度h*,得到P*-h*关系,然后将相同的压力下的试验极顶高度h*与模拟极顶高度h比较,修正初始应力应变关系模型,逐渐逼近,最终得到大应变条件下真应力应变关系。

It is well known that the bulge test is a method to assess mechanical properties and forming performance of the sheet metal materials. Since it is difficult for the thick metal materials to bulge directly, it presents a way that specimen is bulging, which is obtained fiom removing some material in the direction of thickness. Thus, the bulge test will be proposed to determine the mechanical properties of thick metal plate. Finite element models are established based on the corresponding experiments. Stress-strain relation from the simple uniaxial tensile testprovides the initial material constitutive relation, which is used to the finite element analysis. The bulge pressure （p ） vs. height at the pole （ h ） is obtained from the finite element simulation. And through the actual bulge process, the bulge pressure （P^＊ ） and the pole height （h^＊ ） will be recorded. Then the procedure needs minimize the difference between simulated and measured data, bulge pressure vs. height at the pole, by means of constantly correcting the initial stress-strain relation. Eventually the true stress-strain relation with large strain will be obtained.