对裂纹扩展规律Paris公式物理本质的探讨

首先讨论了著名力学家K.Krausz和A.S.Krausz关于Paris公式物理本质研究的成果，从材料的微观结构和裂纹尖端的应力场出发，应用位错动力学理论，热激活能理论和速率过程理论对疲劳裂纹扩展规律进行了微观到宏观的探讨。最终推导出疲劳裂纹扩展速率的一个解析表示式，该式严格地定了Paris公式的两个试验常数，赋予了Paris公式明确的物理意义，从而真实地揭示了Paris公式的物理本质，为这一经验的普遍规律奠定了理论基础。

ON THE PHYSICAL NATURE OF THE PARIS LAW

A theoretical equation of fatigue crack growth is deduced in detail by means of dislocation dynamic theory, thermal activation theory and velocity process theory, with the two test constants in Paris equation being determined theoretically and explained by the microscopic structural parameters of the materials and the conditions of the test environments as well. The proposed theory finally discloses the physical nature of the Paris Law which has been considering an experimental result without theoretical background. It comes true that only measuring the microscopic parameters for one time, the behavior of crack propagation in any test conditions can be obtained. This temperature dependent crack propagation theory is used successfully to describe the crack growth rates of offshore structural steel A537 at different temperatures. The results from the theory are reviewed in accordance with the conclusions of published references.