FRACTURE MECHANICS APPLIED TO RUBBER ABRASION.

Abstract

A NOVEL THEORY HAS BEEN DEVELOPED WHICH DIRECTLY RELATES THE ABRASION OF RUBBER BY A KNIFE EDGE TO ITS CRACK GROWTH CHARACTERISTICS.THE APPROACH IS BASED ON FRACTURE MECHANICS WHICH HAS BEEN SUCCESSFULLY USED TO INTERPRET OTHER FAILUR PROCESSES IN RUBBERS.THE THEORY TREATS THE REMOVAL OF THE RUBBER WHEN A STEADY STATE HAS BEEN REACHED IN THE DEVELOPMENT OF THE ABRASION PATTERN IN THE RUBBER SURFACE.IT IS SUGGESTED THAT CRACK-GROWTH OCCURS INTO THE RUBBER FROM STRESS CONCENTRATIONS IN THE ABRASION PATTERN.AN IMPORTANT POINT IS THAT ONCE A STEADY STATE IS ESTABLISHED THE DETAILED WAY IN WHICH THE PARTICLES OF RUBBER ARE FINALLY DETACHED IS UNIMPORTANT.THE CRACK GROWTH BEHAVIOUR OF THE RUBBER IS MEASURED INDEPENDENTLY USING ESTABLISHED TECHNIQUES.LTHE EXPERIMENTAL APPARATUS IS DESCRIBED AND RESULTS HAVE BEEN OBTAINED AT VARIOUS LOADS AND SLIDING SPEEDS.GOOD AGREEMENT WITH THE THEORY IS FOUND FOR MOST RUBBERS BUT DEPARTURES ARE NOTED FOR NATURAL RUBBER WHICH CRYSTALLIZES ON STRAINING.THE REASONS FOR THESE DEPARTURES ARE DISCUSSED.(A.)