Pre Stressed Modal Analysis of Bolted Cantilever Structure at Different Configurations of Washers

This The bolted joint is the best choice for detachable assembly of components in structures and machines to maintain integrity in fastened structure due to their high reliability, strong load bearing capacity, easy maintenance and inspection at low cost and the washers are generally used to protect joint surface from damage during the tightening process and to distribute the load under the bolt head and nut. However, in many applications bolt connections are often subjected to different types of loading during their service life which reduce the preload on bolted joint and leads to failure of engineering structures. Due to the complex geometry and uneven distribution of loads on a bolted connection, it is difficult to detect region of failure of bolted connection using conventional nondestructive test methods. A vibration-based modal analysis that uses changes in natural frequencies and modes of vibrations of a structure is effective in detecting loosening and failure of bolted joints. The present work is focused on analyzing effect of types, size and combinations of washers on natural frequency of bolted joined by using Pre Stressed Modal Analysis and experimental BUMP test on FFT Analyzer which gives significance of washer to prevent loosening.