复合材料Ⅱ型分层损伤演化声发射监测

ACOUSTIC EMISSION MONITORING ON MODE Ⅱ DELAMINATION DAMAGE EVALUATION OF COMPOSITE MATERIAL

通过风电叶片复合材料Ⅱ型分层扩展力学性能实验,并借助声发射技术手段,研究复合材料[0/0]、[0/45]和[+45/-45]层间界面损伤演化特性。复合材料试件弯曲加载时,采用声发射实时监测整个分层损伤过程。结果表明,[0/0]复合材料分层试件裂纹扩展快、分层面积大、前沿平齐,不稳定扩展对应较多高幅值、长持续时间的声发射信号;受±45°方向纤维作用,[0/45]和[+45/-45]复合材料试件不稳定分层扩展前声发射撞击累积数较高,裂纹扩展相对缓慢,分层面积小,前沿不齐。复合材料分层损伤演化可分为预分层裂纹尖端区域微损伤累积和分层不稳定扩展两个基本的过程。

In order to study the damage evolution of interlaminar interface [ 0/0], [ 0/45 ] and [ ＋45/-45 ] in composites material for wind turbine blades, mode 11 delamination growth experiment of the composites has been conducted by means of acoustic emission technique. In this flexural experiment, real-time acoustic emission monitoring was used during the entire delamination process and the delamination growth. The results show that high speed crack extension, large delaminated areas and planar crack front are obtained for [ 0/0 ] layered composite specimen, and unstable crack extension is associated with high amplitude, long duration time acoustic emission （AE） signal. In the case of [ 0/45 ] and [ ＋/-45 ] composite material specimen, delamination damage and extension are affected by the fibers along ±45° direction, and high AE cumulative hits before unstable crack extension, low crack propagation rate, small delaminated areas and irregular crack front are induced. The delamination damage evolution of the composites could be divided into two basic stages, the micro damage accumulation around crack tip region and delamination unstable extension.