Load Distribution Analysis Of Hybrid Bolted And Bonded Joints

Abstract

The traditional joining methods like mechanical fasteners or adhesives are used in newlinevarious structural applications like airplanes, automobiles, ships etc. These methods newlinehave their own advantages and disadvantages. The mechanical fasteners help is repair newlinework because of easy assembly and disassembly, the joint performance do not depend newlineon condition of base materials but, the mechanical joining method on the other hand newlineincreases the overall weight of the joint, stress concentration and distortion of the base newlinematerials .The increased weight of the joint results in more fuel consumption. Whereas newlinethe adhesives have excellent strength and they also reduce the weight of the joint, but newlinethey fail catastrophically (i.e. suddenly) without prior intimation. This increases the risk newlinefor the type of applications where they are used. Hybrid Joint, which is the combination newlineof the two joining techniques (bolted and bonded) is a good solution to overcome the newlinedrawbacks of the traditional methods. In hybrid joint, due to high stiffness of adhesives, newlinethe maximum load is shared by adhesive and load is transferred to the bolts only after newlinethe failure of adhesives. Thus, the contribution of bolts is minimum. In this study, to newlineincrease the contribution of bolts in hybrid joint load sharing, a low strength adhesive newlineis used. The parameters that affect the performance of the joint are selected by using newlinethe Analytical Hierarchy Process (AHP).The output parameters identified to be failure newlineload and displacement were measured for the different combinations of input newlineparameters .The selected input parameters by AHP method were bolt size, tightening newlinetorque, bolt hole clearance, adhesive type ,adhesive thickness, overlap length and joint newlinematerial. Taguchi s L27 orthogonal array is used to identify the optimum combination newlineof parameters in hybrid joints. From the various parameters studied adhesive type, newlineadhesive thickness and joint material are found to be significant.