Fatigue-cracking evolution of material under load action
When a material element is in a deformed state, two aspects are concerned: 1) the fatigue effects, which are related with the microstructure evolution in spatial domain;2) the cracking initiation and transportation in time domain. The difficulty on treating the material feature evolution is originated from the fact that both effects are happening under the condition that the mechanics equations and boundary conditions are met. Theoretically, they can be described by a Hamilton dynamic system established by a set of general displacement rate functions. In this research, the Hamilton dynamic system is studied by geometrical field theory of deformation. Firstly, referring to the instant configuration, the deformation tensor in spatial domain and the velocity transformation tensor in time domain are established for a dynamic system defined by a set of general displacement rate functions. Secondly, the general deformation tensor in displacement rate form is obtained. From continuum mechanics point, the stress tensor is as a known quantity (which is determined by the working condition of material). Then, the general motion equations of displacement rate are established. Based on them, the typical solutions are divided into two classes: 1) fatigue, volume invariant evolution;and 2) cracking, volume expansion evolution. Both of them have lattice structures. This research shows an engineering way to treat fatiguecracking as a Hamilton dynamic system.
Fatigue cracking Deformation tensor Hamilton dynamic system Geometrical field Rational mechanics
Jianhua Xiao
Measurement Institute, Henan Polytechnic University, Jiaozuo, China
国际会议
2011 International Symposium on Structural Integrity 2011国际结构完整性学术研讨会--核工程结构完整性技术 ISSI 2011
合肥
英文
221-226
2011-10-27（万方平台首次上网日期，不代表论文的发表时间）