含冲击损伤复合材料层压板压缩破坏机制的声发射特性研究

复合材料层压板在压缩破坏过程中包含了丰富的声发射信息.为了研究含冲击损伤的复合材料层压板的压缩破坏机制,采用声发射观察层压板的压缩破坏过程,通过分析声发射信号的特征规律,表征了在压缩载荷下材料损伤的形式及其演化过程.结果表明:通过对声发射参数(撞击计数、能量、幅值、事件位置)和载荷曲线进行综合分析,发现损伤的发展过程经过了初始阶段、平稳扩展期和断裂阶段,冲击造成的分层区域最先出现屈曲并最早破坏；在损伤初始阶段和平稳扩展期间,损伤是一种渐进式的增长,层压板具有一定的承载能力；在断裂阶段损伤快速扩展,层压板的承载能力迅速下降,在出现纤维密集断裂的现象后整体破坏.

Experimental Investigation on Compression Failure Mechanism of Composite Laminates with Impact Damage Based on Acoustic Emission

Compression failure process of composite laminates includes a lot of acoustic emission information. In order to study the compression failure mechanism of composite laminates with impact damage, the compression failure process was observed by acoustic emission. Through analyzing the characteristics of acoustic emission signal, the material damage form and its evolution under compressive loading were characterized. Results show that through comprehensive analysis of acoustic emission parameters, including impact count, energy, amplitude and event location etc. and loading curve, it is found that the developing process of damage undergoes three stages including initial stage, steady extension stage and break stage. The buckling caused by impact appears first at layered area, where the damage also emerges earliest. During the initial stage and steady extension period, damage presents progressive growth, and the laminate has a certain carrying capacity; while during the break stage, damage expands rapidly, the carrying capacity of laminate declines rapidly; finally, the overall damage appears after intensive fiber breakage.