Studies on wear of spherical interface Using newly designed and developed Hip simulator TRIFEMUR

Abstract

This thesis presents an experimental study on wear of the spherical newlinejoints subjected to harmonic oscillating load and three motion components newlinesimilar to that of the hip joint A simplified hip joint simulator Trifemur has newlinebeen designed and developed for this purpose vide Indian Patent No 198349 newline 2003 As a three station spherical interface wear testing machine it is meant newlineto handle simultaneously a set of three rigid hemispherical shell and newlinematchingly articulating spheres as test specimen Shells of phosphor bronze newlinecopper and cast iron as wearing materials against hard counter face of newlinestainless steel spheres of 25 mm were chosen All tests were conducted under newlinedry reciprocal sliding condition at a cycle frequency of 0 75 Hz This new newlineapparatus customized for evaluating prosthetic implants has been utilised in newlinethe pilot and regular test runs for two static load variations of 600 and newline1100 N newlineEach test duration lasting for 1 8 10 5 cycles 8150 minutes newlinecovers the run in and spans considerably into the steady state wear regime newlineWear of the shells measured gravimetrically at intervals subsequent rendering newlineof the biphasic wear curve and wear factors computed thereby for various newlinespecimen are presented as the most tangible output and breakthrough of this newlinefirst experimentation Macrographs of worn out surfaces variation in centerline newlineaverage roughness parameter Ra details of wear debris and acoustic newlineemission signals obtained are reported and discussed In conclusion this study newlineestablishes the potential of the new simulator Trifemur as spherical wear newlinetester which leads to standardize tribo testing of spherical joints similar to newlinestandard pin on disc testing for planar interfaces newline