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

Abstract

Abstract: 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 Ⅱ 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.

Key words: wind turbine blade, composite, end notched flexure test, delamination damage, acoustic emission

CLC Number:

TB332

LI Ya-juan, ZHOU Wei, LIU Ran, ZHANG Xue-mei. ACOUSTIC EMISSION MONITORING ON MODE Ⅱ DELAMINATION DAMAGE EVALUATION OF COMPOSITE MATERIAL[J]. COMPOSITES SCIENCE AND ENGINEERING, 2015, 0(1): 54-58.

References

[1] 王耀东, 何景武, 夏盛来. 复合材料叶片结构设计中的几个关键问题探讨[J]. 玻璃钢/复合材料, 2012,(1):34-38.
[2] Ghasemnejad H, Occhineri L, Swift-Hook DT. Post-buckling failure in multi-delaminated composite wind turbine blade materials[J]. Materials and Design, 2011, 32(10): 5106-5112.
[3] Barrett J D, Foschi R O. Mode Ⅱ stress intensity factors for cracked wood beams[J]. Engineering Fracture Mechanics, 1977, 9(2): 371-378.
[4] 于志成. 复合材料Ⅱ型层间断裂韧性试验方法研究[J]. 航空材料学报, 1997, 17(4): 54-61.
[5] 孙先念, 陈浩然, 苏长健, 刘相斌. 含分层损伤复合材料层合板分层扩展研究[J]. 力学学报, 2000, 32(2): 223-232.
[6] Szekrényes A. Interlaminar stresses and energy release rates in delaminated orthotropic composite plates[J]. International Journal of Solids and Structures, 2012, 49(18): 2460-2470.
[7] Segurado J, Llorca J. A new three-dimensional interface finite element to simulate fracture in composites[J]. International Journal of Solids and Structures, 2004, 41(11-12): 2977-2993.
[8] Turon A, Dávila C G, Camanho P P, et al. An engineering solution for mesh size effects in the simulation of delamination using cohesive zone models[J]. Engineering Fracture Mechanics, 2007, 74(10): 1665-1682.
[9] 刘德博, 关志东, 李星, 何为. 基于界面单元的复合材料Ⅱ型层间损伤分析[J]. 复合材料学报, 2012, 29(5): 151-156.
[10] 汪星明, 郭耀红, 朱庆友, 柳泽. 复合材料无损检测研究进展[J]. 玻璃钢/复合材料, 2012,S1:261-265.
[11] Hajikhani M, Ahmadi M, Farjpour M, et al. Strain energy release rate assessment in mode I delamination of foam core sandwich composites by acoustic emission[J]. Journal of Composite Materials, 2011, 45(22): 2271-2277.
[12] Dutton A G, Blanch M, Vionis P, et al. Acoustic emission monitoring from wind turbine blades undergoing static and dynamic fatigue testing[J]. Insight, 2000, 42(12): 805-808.
[13] Goutham R K, Vishal S, Mark J S, et al. Monitoring multi-site damage growth during quasi-static testing of a wind turbine blade using a structural neural system[J]. Structural Health Monitoring, 2008, 7(2): 157-173.
[14] 李艳菲, 李敏, 顾轶卓, 张佐光. 风电叶片用真空灌注型环氧树脂及其复合材料性能研究[J]. 玻璃钢/复合材料, 2012,(4):109-114.
[15] Carlsson L A, Gillespie J W, Pipes R B. On the analysis and design of the end notched flexure (ENF) specimen for mode Ⅱ testing[J]. Journal of Composite Materials, 1986, 20(6): 594-604.