材料参数错配对复合层板材料裂纹扩展的影响

INFLUENCE OF MATERIAL PARAMETER MISMATCH ON CRACK PROPAGATION IN COMPOSITE LAMINATES

对于垂直于复合层板材料界面的裂纹,其扩展路径通常有多种形式。通过分析裂纹扩展过程中裂纹尖端应力场,判断裂纹尖端驱动力的大小,进而分析其裂纹的扩展路径。以压力容器常用材料钛-钢(TA2-Q235B)复合层板为研究对象,通过数值分析,讨论两种材料的弹性模量错配、强度错配对裂纹扩展的影响。分析结果表明:这两种因素对裂纹扩展均产生了一定程度的促进或抑制作用。当裂纹由高强度材料向低强度材料扩展时,裂纹扩展速率增加,反之减小;当裂纹由高弹性模量材料向低弹性模量材料扩展时,裂纹扩展速率增加,反之减小。无论裂纹从哪个方向扩展,距离界面越近,其影响效果越明显,并且当裂纹扩展到达界面时,裂纹扩展速率都有一定程度的减小,或发生止裂现象。

The propagation path of cracks perpendicular to the interface of composite laminates usually takes many forms. By analyzing the stress field of crack tip during crack propagation, the driving force of crack tip is determined, in this way, the crack propagation path is analyzed. This article’s research object is the titanium-steel(TA2-Q235 B) composite laminate, a commonly used material for pressure vessels, the influence of the mismatch of elastic modulus and strength of the two materials on crack propagation is discussed by numerical analysis. The analysis results show that both two factors have a certain degree of promotion or inhibition of crack growth. When the crack propagates from a high-strength material to a low-strength material, the crack propagation rate increased and conversely decreased;when the crack propagates from a high elastic modulus material to a low elastic modulus material, the crack propagation rate increased and conversely decreased. No matter which direction the crack propagates from, the closer it is to the interface, the more obvious its effect will be. When the crack propagates to the interface, the crack propagation rate will decrease, or crack arrest will occur.