US-Egypt Cooperative Research: Effects of Machining Parameters on the Strength and Fatigue Behavior of Bolted Joints in GFRP Composites

描述：该奖项是为了支持由伊利诺伊州迪卡尔布北伊利诺伊大学（NIU）机械工程系Mohamed a . Seif博士和埃及扎加齐格大学机械设计与生产工程系Usama Khashaba博士和研究与研究生院Gamal Nawara博士共同开展的一项联合研究项目。随着复合材料在结构构件中的广泛应用，为了方便与主要承重结构的螺栓或铆接，在层压板上钻孔已成为必要。钻孔过程中存在的主要问题是应力集中、分层和微裂纹，这些问题严重影响了复合材料的性能。pi将研究钻孔参数对复合材料力学性能的影响。这包括不同切削条件（进给和速度）、加工操作（CNC、激光和水射流）以及钻头的尺寸和形状的影响。在单轴静态和疲劳载荷条件下，孔的质量对缺口强度、销承载强度和螺栓连接强度的影响也将进行研究。还将特别关注在各种装配条件下的接头性能，如螺栓拧紧扭矩、垫圈尺寸、螺栓间隙和直径/宽度比。光学显微镜、扫描电子显微镜和激光测量技术将用于本研究。范围：该项目将有助于更好地理解复合材料中螺栓连接的行为。此外，工程模型的发展将有助于提高复合材料在各种操作条件下的基础研究。这项合作涉及一位在该领域有建制和经验的美国科学家、埃及一所规模相对较小的大学的两名研究人员以及该国的一些工业组织。

0210475SeifDescription: This award is for support of a joint research project by Dr. Mohamed A. Seif, Department of Mechanical Engineering, Northern Illinois University (NIU), Dekalb, Illinois, and Dr. Usama Khashaba, Department of Mechanical Design and Production Engineering, and Dr. Gamal Nawara, Research and Graduate Studies, both at Zagazig University, Zagazig, Egypt. With the wide use of composite materials in structural components, it has become necessary to drill holes into laminates to facilitate bolting or riveting to the main load-bearing structures. Stress concentration, delamination and microcracking are the main problems associated with drilled holes, which significantly reduce the composites' performance. The PIs will investigate the effect of the drilling parameters on the mechanical properties of composites. This includes the effect of different cutting conditions (feeds and speeds), machining operations (CNC, laser, and water jet), and the size and shape of the drills. The influence of the quality of the hole on the notched strength, pin bearing strength and bolted joint strength under uniaxial static and fatigue loading conditions will also be examined. Special interest will also be given to study the joint performance under various assembly conditions such as the bolt tightening torque, the washer size, the bolt clearance, and the diameter/width ratio. Optical microscopes, SEM, and laser measurement techniques will be used in this investigation. Scope: This project will help in establishing a better understanding of the behavior ofbolted joints in composite materials. In addition, the development of engineering models will contribute to improve basic studies of composite materials under various operationalconditions. The collaboration involves an established and experienced U.S. scientist in the field and two researchers in a relatively small university in Egypt as well as a number of industrial organizations in that country.