Estimation of energy dissipation in Lap lap _Joints joints using Scaling scaling Approachapproach

Under high loads, it is vital to predict the vibration levels in assemblies in the early design phase. Today there is a good understanding of the dynamics of individual components, but this confidence reduces considerably for a large assembly with joints in it. One of the key issues is the localized damping introduced due to the joints.joints. The prediction of the damping due to micro and macro sliding is very important. Joint damping prediction due to micro and macro sliding in joints is important. This paper describes a method to estimate the damping in an actual lap joint from a scaled physical model of a joint. This has the advantage of using lower capacity equipment for estimating joint damping by inducing slip under various loading conditions. To start with a detailed nonlinear Finite Element Analysis (FEA) of the lap joint was is _used to estimate the damping due to micro and macro sliding taking place in the jointfrom the hysteresis curve generated under various loadings; the damping is due to micro and macro sliding taking place in the joint. _The results from the simulations verified confirm the power law dependence of the energy dissipation in joints on excitation amplitudes reported in the literature. The dependence of dissipation energy on Joint joint pre-load, friction coefficient was is _also examined. The FEA simulations confirmed the possibility of using scaling to gather estimates of damping under various loads in lap joints. This is useful during the early design phase when actual hardware is unavailable. Validation of the FEA is currently underway using an experimental setup. _If successful, this idea will can _help change assembly based vibration prediction from a ‘retrospective or tuning’ based approach towards a more predictive based approach.