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本文对六种多向铺层的碳纤维增强环氧复合材料的拉伸破坏性能进行了研究,并采用声发射技术监测其损伤扩展过程,分析了它们的破坏机理。 新型的高性能碳纤维增强环氧复合材料应用于宇航、机械及体育器具等,由于工作条件及受力情况是复杂的,采用多向铺层才能满足受拉、压、弯、剪、扭等不同载荷的分别组合,具体铺层设计要针对主要承力情况来确定。多向铺层复合材料的损伤破坏比单向铺层的情况复杂,更需要采用试验的手段来研究它们的力学性能和破坏机理。在非破坏性测试中声发射技术的特点在于能够配合加载装置在进行试验过程中检测并记录复合材料的破坏过程,而且不移动探头的位置即可监测材料的较大区域,因此应用愈来愈多。声发射技术是利用材料或构件受力变形或损伤过程中应变释放产生弹性波这一原理来检测材料的缺陷、退化和破坏,评定材料的性能。声发射技术可以检测复合材料的剪切破坏及拉伸屈服破坏、分层及纤维断裂、粘接强度等。 本工作对六种多向铺层碳/环氧复合材料(包括0/90、±45°、30/60和三种碳布)进行拉伸试验,确定了它们的强度、模量、最大应变率及泊松比,给出六种不同铺层的应力应变关系以及声发射信号量的关系。采用声发射技术配合显微镜观测手段分析不同铺层的碳/环氧材料的声发射表征?
In this paper, the tensile failure behavior of six kinds of multidirectional carbon fiber reinforced epoxy composites were studied. The damage propagation process was monitored by acoustic emission technique and their failure mechanisms were analyzed. New high-performance carbon fiber reinforced epoxy composite materials used in aerospace, mechanical and sports equipment, due to the working conditions and the force situation is complex, using multi-directional ply to meet the tension, pressure, bending, shear, torsion, etc. The combination of load, the specific design of the ply for the main bearing capacity to determine. The damage of multidirectional composite materials is more complicated than that of unidirectional composite materials, and more experimental methods are needed to study their mechanical properties and failure mechanism. Acoustic emission technology in non-destructive testing is characterized by the ability to detect and record the failure of the composite during loading and unloading, and to monitor the larger area of the material without moving the position of the probe, thus increasing its application many. Acoustic emission technology is the use of materials or components by deformation or damage during the strain release elastic wave generated by the principle of detecting defects, degradation and destruction of materials to assess the performance of the material. Acoustic emission technology can detect the shear failure of composite materials and tensile yield failure, delamination and fiber breakage, bonding strength and so on. In this work, tensile tests were carried out on six kinds of multidirectional carbon / epoxy composites (including 0/90, ± 45 °, 30/60 and three kinds of carbon cloths) to determine their strength, modulus, maximum strain Rate and Poisson’s ratio, the relationship between the stress and strain of six different plies and the relationship between the acoustic emission signal amount and the stress-strain relationship are given. Acousto-Emission techniques were used to analyze the acoustic emission characteristics of different layers of carbon / epoxy materials in combination with microscope observation.