Numerical Investigation of Effect of Elasto Plastic Behavior Around The Notches Under Cyclic Loading

Abstract

Aluminium alloys is used around 75-80% in the aero structure applications due its newlinelow density and high strength which helps in the reduction fuel consumption of the aircraft. newlineBut, the aero structure consists of fastener hole which causes premature failure due to crack newlinepropagation from hole surface due to high stress concentration. In order to resolve the newlineproblem, many researchers have worked to increase the fatigue life by many metals forming newlineprocess. Air craft materials captured the global market of around 42% of worth of USD 2.6 newlinetrillion and they are slowly increasing their applications in space engineering applications. newlineBut, these advanced materials have limited usage, due stress concentration, due elasto-plastic newlineand toughness resistance. In this context, many research works have been focused to develop newlinehigh toughness and lower stress concentration techniques by experimental methods. But, newlineonly few or no works has investigated the elasto-plastic behavior of Al using numerical and newlineother methods. The objectives of the work were to investigate: newline1) Experimental and numerical analysis of Elastoplastic behavior of Al alloys. newline2) Effect of cold hole expansion on residual stresses and newline3) To find the enhancement in properties i.e. circularity, surface finish, hardness in newlinehole vicinity, grain structure variation and residual stress which effects the fatigue newlinelife of the structure due to the presence of fastener hole. newlineThe present investigation is concerned with fracture characteristics of elastic and newlineelastoplastic materials. An attempt is made to evaluate the stress intensity factor for the newlineelastic case, plastic zone and limit load for the elasto-plastic case. The elasto-plastic cyclic newlinetests were conducted by using tensile machine with a pair of strain gauges.