受剪复合材料层合板开口应力应变分析研究

Study of Stress and Strain for Composite Laminated Plates with Cutout Subjected to Shear Load

复合材料比强度、比刚度高,抗疲劳性能好,因此,越来越广泛地应用在航空、汽车和许多工程结构中,尤其是在航空领域。使用复合材料不但可明显减轻飞机结构质量,提高其结构疲劳寿命,还可提高结构效率,改善特定的气动性能,提高战斗机的作战性能。因此,在过去的30年里,复合材料在军用、民用飞机上的用量不断增加。复合材料在飞机结构上的用量增加的同时,在飞机结构中的使用范围也不断拓宽,使用部位从受力不大的部件如整流罩、前后缘、扰流板等次承力部位,到受力很大的水平安定面、垂直安定面、机翼等。随着复合材料的广泛应用,也会遇到一些新的问题。如在机翼结构中,尤其是在带整体油箱的机翼结构上(蒙皮、梁、肋),由于使用要求,如保证油路、工艺施工、检查维修、设备安装、管道通过等,不可避免要在结构上布置各种类型、大小不同的开口或开孔。开口会改变结构的受力特性。因此有必要对复合材料层合板开口进行仔细的研究。本文主要针对受剪作用的复合材料层合板,运用工程软件计算分析了多种开口形状、开口方位、开口倒角大小等对层合板应力、应变集中的影响。对于薄板而言,易发生失稳破坏,本文最后对开口形状对层合板稳定性影响也进行了探讨。

Composites is commonly used in aircraft, automobile and many engineering structures for its excellent characteristics, such as high specific strength, high specific stiffness, and better anti-fatigue performance, especially application in the aviation field. By using composites, not only will the structural fatigue life and structure efficiency of aircraft be increased, but also aerodynamic and operational performance be improved. As a result, dosage of the composites in the military aircraft and civil aircraft has been increased continually in the past thirty years. Along with the increased dosage of the composites, the application range also has been expended, from the low force bearing structures such as fairing, front and rear edge, and spoiler to high force bearing structures, for example, the horizontal stabilizer, vertical stabilizer, wing and so on. Some new problems appear with the application of the composites. For instance, for the wing structure with integral fuel tank （skin, beam, rib）, on account of the request of the design, such as gas flowing smoothly, check and maintenance, equipment installation, and pipeline, etc, cutting many kings of holes in structures is unavoidable. However, when holes were cut from plate structures, mechanical behaviors of the structures were changed. So it is necessary to study the cutouts in the composite laminates. With finite element software, the influence of shape, position and chamfer angle of cutouts in the composite laminate subjected to shear load on stress and strain concentration was investigated in this paper. Stability is of great importance for thin plates, so stability analysis of composite laminate with various cutouts is also included.