三维损伤容限设计:离面约束理论与疲劳断裂准则

Three-dimensional Damage Tolerance Design:Out-of-plane Constraint Theory and Fatigue/Fracture Criteria

损伤容限设计是为保证含裂纹结构安全而发展的抗疲劳断裂设计方法。其核心思想是:承认构件中存在初始裂纹,基于断裂力学理论对裂纹疲劳扩展寿命和结构剩余强度进行分析和试验验证,并结合定期检查,保证结构在服役中裂纹不会发生失稳扩展。对于承受交变载荷的结构,如飞机、轮船、压力容器等,损伤容限设计思想已成为保证大型装备服役安全性和经济性相统一的科学设计理念。在回顾飞机结构强度设计理念发展的基础上,总结了损伤容限设计思想的科学内涵;阐明了损伤容限设计的理论基础—断裂力学—由二维理论发展到三维理论的必要性;详细介绍了三维损伤容限设计的理论、方法与应用。最后,对损伤容限设计的进一步发展作了简要展望。

The damage tolerance design is developed to ensure the safety of structures with cracks based on anti-fatigue and fracture design strategy. The key idea of this design principle is as follow:to avoid unstable crack propagation in engineering structure with inevitable initial defect, the fatigue crack growth life and residual strength of the structure with crack should be analyzed and verified in combination with regular maintenance. For the structures subjected to alternating loadings-such as aircrafts, ships, pressure vessels and so on-the conception of damage tolerance design has been widely recognized as the scientific principle to ensure safety and economic efficiency of large-scale equipments. In this paper we firstly summarize the scientific connotation of damage tolerance design based on reviewing the development of strength design concept for aircraft structures. Then we clarify the necessity for developing the theoretical basis of damage tolerance design from two-dimensional fracture theory to three-dimensional fracture theory. After that, the theory, method and application of three-dimensional damage tolerance design were described in detail. Finally, the future development trends of damage tolerance design are briefly prospected.