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断裂力学的主要成果就是找到了引起结构(或试样)破坏的作用应力和结构中(或试样)存在的缺陷尺寸或可能的预裂纹间的定量关系;而这种关系正是通过测定材料的断裂韧性联系起来的。所以测定材料断裂韧性是一项十分重要的试验,但是十多年来,我们测定的断裂韧性属于开裂韧性,对于中低强度钢结构来说,开裂与快速扩展断裂差距很大,故开裂韧性显得非常保守。最近,译者有机会在美CE 公司MML 实验室参观了一项止裂韧性试验,了解到当前美国对中低强度钢材料广泛开展止裂韧性测试研究,用材料止裂韧性来鉴定中低强度钢材料抵抗裂纹扩展的能力。这是断裂韧性测试的新课题,为此ASTM 提出了这份建议性的新标准。虽然本标准在美国国内尚没有公开发表,但对进一步研究断裂韧性测试可能有帮助,所以翻译出来供广大测试和研究人员参考。应当说明,译者有幸得到哈尔滨工业大学王铎教授的帮助和指导,并对译文作了详细校对和重要订正,特此表示感谢。
The main result of fracture mechanics is to find the quantitative relationship between the action stress that causes the failure of the structure (or specimen) and the size of the defect (or specimen) present in the structure or possible pre-cracking; and this relationship is determined by measuring the material The fracture toughness of the link. Therefore, the determination of material fracture toughness is a very important test, but more than a decade, we determine the fracture toughness belongs to the fracture toughness, for low-strength steel structure, the gap between the crack and rapid expansion of a great gap, so the fracture toughness appears Very conservative. Recently, the translator had a chance to visit a cease-fracture toughness test at MML Laboratory of the US CE Company. He learned that at present, the United States has carried out a wide range of testing on the crack-arresting toughness of medium and low-strength steels and the medium- and low- The ability of steel to resist crack propagation. This is a new topic in fracture toughness testing, for which ASTM proposed this proposed new standard. Although this standard has not been published in the United States, it may be helpful to further study the fracture toughness test. Therefore, it is translated for reference by the majority of test and research personnel. It should be noted that the translator was fortunate enough to have the help and guidance of Professor Wang Duo of Harbin Institute of Technology and he has given detailed proofreading and important revision of the translation.