https://iaeme.com/Home/journal/IJMET 70 editor@iaeme.com International Journal of Mechanical Engineering and Technology (IJMET) Volume 14, Issue 03, May-June 2023, pp. 70-90. Article ID: IJMET_14_03_007 Available online at https://iaeme.com/Home/issue/IJMET?Volume=14&Issue=3 ISSN Print: 0976-6340 and ISSN Online: 0976-6359 © IAEME Publication ANALYSIS FOR FLAT-RECESS HEAD COUNTERSINK COMPOSITE BOLTED CONNECTION UNDER TENSILE LOADING A.Moussa Faculty of Energy and Environmental Engineering, The British University in Egypt, Al-Sherouk, City, Cairo, Egypt M.Shazly Mechanical Engineering Department, Faculty of Engineering, The British University in Egypt, Al-Sherouk City, Cairo, Egypt ABSTRACT In recent years, the use of composite connections in various assemblies has grown, particularly in the infrastructure, aerospace, marine, wind energy, and automotive industries. Modern synthetic fiber composite materials are popular because they have a high strength to weight ratio, are flexible, can carry heavy loads, have improved aesthetics, and can acquire an aerodynamics feasibility. As a result, it is important to maintain the Composite surface’s safety and continuous operation. This paper examines the behavior of composite bolted joints using a specific recess flat head countersink bolt to be inserted in the composite bodies without any influence on aerodynamics performance and with the head sunk into the surface of composite laminates. The analysis requires investigating the behavior of these bolts under tensile loading. Four samples of glass fiber reinforced polymer (GFRP) composites were used in the experiment, which used single and double joint single lap tensile joints. Vacuum- assisted resin infusion (VARI) was used to create the samples. In the current work, triaxial laminates (0, -45°, 45°) were used as stacking sequence of laminate. In order to evaluate the joint strength and failure modes under tensile loading, tensile tests were applied to this layup. To analyze the impact of the joint design parameters on stiffness and strength, finite element (FE) models were created. To verify and validate the experimental findings, FE models were developed. In a parametric analysis, joint width (25 mm for a single bolted joint and 50 mm for a single lab, double bolted joint) and bolt diameter (4 and 6 mm) were compared. The 4 mm bolt diameter is applied to a joint specimen with less thickness than that for the joint specimen secured with the 6 mm bolt. According to the results of the experimental test, joints started to fail when bolts were pulled through until shear-out failure occurred. According to the study, it was shown that the failure stress for a double bolted joint compared to a single bolted junction rose by almost twice as much for the same bolt size and different type of bolted joint configuration.