利用位移引伸计测定薄板单轴损伤演化曲线的试验方法研究

一套准确而又简便的测试损伤变量的实验方法，对于推动连续介质损伤力学的工程应用是至关重要的。本文系统研究了利用位移引伸计测定薄板材料单轴损伤演化曲线的试验方法。采用引伸计测量大圆弧变截面试样中心部位某一标距段的伸长量，然后计算得到弹性模量的变化，进而确定损伤变量。文中就试样形状尺寸的确定、主损伤区弹塑性大应变的测控和卸载弹性模量的稳定性、与精确测量等关键测试技术问题进行了深入细致的分析和实验研究，并从多角度对该试验方法的正确性进行了实验验证。文中还介绍了该试验方法在确定LY12-CZ铝合金薄板单轴损伤演化曲线的应用，实验表明本文建议的试验方法是简便有效的，初步奠定了发展标准化损伤曲线测试方法的基础。

Testing Methods for Determining the Uniaxial Ductile Damage Curve of Thin-Plates by Using Clip Gage

Simple testing methods for accurately determining damage parameters is important for the engineering application of continuum damage mechanics (CDM). This paper systematically examine a simple test method for determining the uniaxial ductile damage curves of thin-plates. The elongation of the gauge length near the necking area of specimen was measured by using clip gage, so that the elastic modulus of damaged material could be determined. Thus, the damage parameters under various plastic-deformation states were obtained by calculating the ratio of the changed modulus to initial modulus. The size requirements for the specimens and gauge length were discussed both analytically and experimentally. Particularly, some special techniques for measuring the elasticity modulus of damaged materials, such as the stability of the repeated-unloading elastic modulus and measuring and controlling of large strain, were proposed. The test results for the thin-slabs of LY12-CZ aluminum alloys show that the test method suggested in this paper for determining the uniaxial ductile damage curves of thin-slabs is feasible and effective. The work described is intended to form the technical base for the development of a standard damage curves test method.