Finite solid circular cylinders subjected to arbitrary surface load. Part II - Application to double-punch test

This paper derives the stress distributions within a finite isotropic solid circular cylinder of diameter 2b and length 2h under the double-punch test . which was introduced by Chen (1970) for the determination of the indirect tensile strength of concrete. The stresses induced by the two rigid circul ar punches of diameter 2a at the top and bottom of the solid cylinder are m odeled by considering contact problem. The general stress analysis discusse d in a companion pager (Part I) is used to obtain the stress field within t he solid. In general, tensile stress concentrations are developed beneath t he punches compared to the roughly uniform tensile stress at the central po rtion of the axis of the cylinder. The maximum tensile stress in the tensil e zone decreases with the increase of Poisson's ratio and a/b, but is rough ly independent of a/b. For small Poisson's ratio (say about 0.1) and a/b (s ay smaller than 0.1), the assertion made by Chen (1970) and Marti (1989) th at a uniform tensile stress field, similar to that of the Brazilian test, i s developed along the axis of symmetry is incorrect. The tensile strength i nterpreted from the present analysis is found comparable to the formula pro posed by Bortolotti (1968) for a/b > 0.2 and agrees well with the experimen tal data, and thus provides an improvement over Chen's (1970) original form ula. (C) 2000 Elsevier Science Ltd. All rights reserved.