摘要
在数值计算的基础上提出了一个弹塑性材料动态起裂韧度的J表征和测试方法这一方法利用自行研制的间接杆-杆型冲击拉伸试验装置,对周边切口的短圆柱试件实施基于一维试验原理的弹塑性材料动态断裂试验;利用试件两端的平均载荷-相对位移曲线(P-δ)或平均载荷-裂纹张开位移曲线(P-Δ),推广Rice远场公式获得动态J积分;采用柔度变化率法确定裂纹起裂点,从而得到动态起裂韧度J_(ID)。这一方法的优点在于利用P-δ或P-Δ曲线将外力对试件所做的与裂纹运动无关的质心惯性运动动能近似地从总能量中分离出来,且平均载荷P在起裂前以至失稳扩展前是单调增的,同时试验获得的P-δ和P-Δ曲线光滑,这使得用J积分作为裂纹尖端的表征参量以及用柔度变化率法确定起裂点和失稳点具有坚实的物理基础。
By using the self-designed bar-bar tensile impace apparatus, a novel test method for
studying dynamic fracture-initiation has been proposed based on the one-dimensional test principle.
The curve of average load--relative displacement (P-δ) is smooth before unstable crack growth, and
the kinetic energy which does not contribute to the crack growth can be disposed from total work made
by external-force to the specimen. The fracture-initiation point is determined by compliance changing
rate method. The testing results show that these methods are feasible and effective. The dynamic J-
integral, which is adopted as a characteristic parameter for elastic-plastic material under impact
loading, is calculated from P-△ and P-δ curves by using the formula proposed by Rice J R. The J-
integral at fracture initiation is employed to describe the dynamic fracture-initiation toughness of elastic-
plastic material and experimental results indicate that J_(ID) can be regarded as a material constant.
出处
《固体力学学报》
CAS
CSCD
北大核心
2003年第2期185-191,共7页
Chinese Journal of Solid Mechanics
