Acta Geotechnica | 2019
Experimental investigation on the effect of wear flat inclination on the cutting response of a blunt tool in rock cutting
Abstract
A vast majority of experimental researches focuses on the cutting action of a sharp cutter, while there has been limited experimental work devoted to the study of the contact process at the wear flat-rock interface. The specific objective of this study is to determine the effect of the wear flat inclination angle ($$\\beta$$β) with respect to the cutter velocity vector ($$\\varvec{v}$$v) on both the contact stress ($$\\sigma$$σ) and friction coefficient ($$\\mu$$μ) mobilized at the wear flat-rock interface. An extensive and comprehensive set of cutting experiments was carried out on thirteen different sedimentary quarry rock samples using a state-of-the-art rock cutting equipment. A unique cutter holder was purposely designed and manufactured along with a precise experimental protocol implemented in order to change the back rake angle and therefore the inclination $$\\beta$$β by steps of $$0.10^{\\circ }$$0.10∘. The experimental observations confirm the existence of three regimes of frictional contact (identified as elastic, elasto-plastic and plastic) for all rock samples. Further, the results suggest that the scaled contact stress is predominantly controlled by a dimensionless number $$\\eta =\\frac{E^{*}\\tan \\beta }{q}$$η=E∗tanβq with $$E^{*}$$E∗ the plane strain elastic modulus and q the rock strength.