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一、引言由于下列两个主要原因,使目前J积分和COD试验方法的标准采用了所谓多试样阻力曲线的方法: (1) 到目前为止,还沒有一个具有一定可靠性及普遍适用性的关于裂纹起裂和扩展的物理监测手段;(2)即使用物理监测方法定出开裂点来测得材料的起裂韧性,也只是材料断裂特征的一个侧面,而材料抵抗裂纹继续扩展的能力则需要用阻力曲线来描述。今年国家标准局批准颁布的“利用J_R阻力曲线确定金属材料延性断裂韧度的试验方法”,(简称J积分标准“GB 2038”) 和“COD试验方法”(GB 2358),均采用了多试样阻力曲线方法,并要求得到尽可能均匀分布的试验点,即在要求的Δa范围内,使各试样的Δa分
I. INTRODUCTION The so-called multi-sample resistance curve method has been adopted for the current standards of J-integration and COD test methods for the following two main reasons: (1) To date, there has not been a single one that has certain reliability and general applicability Physical monitoring of crack initiation and propagation; (2) even if the physical monitoring method is used to determine the initiation of fracture to measure the fracture toughness of the material, it is only one side of the fracture characteristics of the material and the ability of the material to resist further propagation of the crack Need to use the resistance curve to describe. This year the National Bureau of Standards approved the promulgation of “the use of J_R resistance curve to determine the ductile fracture toughness of metallic materials test method” (referred to as the J integral standard “GB 2038”) and “COD Test Method” (GB 2358) Like resistance curve method, and asked to be as evenly distributed as possible test points, that is required in the range of Δa, so that each sample Δa points