The Ability Of Polyurethane Foam Slabs To Withstand The Effect Of Repeated Compressions Is Determined With The Help Of A Shear Fatigue Test. In This Test, Test Specimen In Shape Of A Square Block Is Held Over A Flat Reciprocating Platform And Is Pressed Down From The Top By A Horizontal Cylindrical Roller Inclined At An Angle Of 15° To The Direction Of Motion Of The Platform. The Platform Is Moved For A Specified Number Of Cycles And The Effect Of Repeated Compressions Produced On The Test Specimen Is Evaluated By Finding The Change In Its Thickness And Indentation Hardness Index cont .