摘要
通过有限元数值模拟和疲劳裂纹扩展试验,研究了铝合金材料在Ⅰ-Ⅲ复合型加载条件下的疲劳裂纹扩展规律,得到了在不同加载情况下裂纹的应力强度因子、裂纹前缘能量场和塑性区半径.在分析Ⅰ型拉力载荷对裂纹扩展的基础上,着重分析了Ⅲ型加载对Ⅰ型裂纹应力强度因子及裂纹前缘能量场的影响.结果表明:应力强度因子KⅠ随着Ⅲ型加载的增大而减小,而裂纹附近塑性区半径增大.进行Ⅲ型静态加载会使疲劳裂纹扩展速率减小,在一定范围内,Ⅰ-Ⅲ复合型疲劳裂纹扩展速率随着Ⅲ型加载的增加而减小;而在进行Ⅲ型循环加载会使疲劳裂纹扩展速率增大,在一定范围内,Ⅰ-Ⅲ复合型疲劳裂纹扩展速率随着Ⅲ型加载的增加而增大.
Fatigue crack propagation laws of aluminum alloys under Ⅰ-Ⅲ combined loading were investigated by finite element simulation and fatigue crack growth experiment,and the stress intensity factors under various loading conditions,the energy field around the crack front and the radius of the plastic zone were obtained.The effects of mode Ⅲ loading on the energy field around the crack front and the stress intensity factor under mode Ⅰ loading were analyzed on the basis of studies on mode Ⅰ loading.Numerical results show that under the condition of Ⅰ-Ⅲ combined loading,the stress intensity factor decreases with the increasing of mode Ⅲ loading,but the radius of the plastic zone near the crack increases.Mode Ⅲ static loading can slow down fatigue crack propagation,and to some extent,the fatigue crack growth rate under combined Ⅰ-Ⅲ loading decreases with the increasing of mode Ⅲ static loading.Mode Ⅲ cyclic loading can speed up fatigue crack propagation,and to some extent,the fatigue crack growth rate under Ⅰ-Ⅲ combined loading increases with the increasing of mode Ⅲ loading.
出处
《北京科技大学学报》
EI
CAS
CSCD
北大核心
2011年第6期734-738,共5页
Journal of University of Science and Technology Beijing
关键词
材料疲劳
铝合金
疲劳裂纹扩展
应力强度因子
加载
fatigue of materials
aluminum alloys
fatigue crack propagation
stress intensity factors
loading
