Professor of mechanical engineering, Faculty of Science and Engineering, Ritsumeikan University, Kyoto,
A new method to estimate a reliable value of the bending modulus of elasticity E from apparent moduli E′ calculated from gradients of crosshead travel versus load for three-point bend tests on specimens at different support spans L is presented. The equation 1/E′ = 1/E + C/L, where C is a constant, is proposed for this estimation. Flexure tests were run at various support spans on specimens of various widths and made of three kinds of materials (a type of polyvinyl chloride and two types of fiber-reinforced materials). Then the values of E′ obtained from the tests at the longest spans were compared with the extrapolated moduli E″ at those same spans, calculated by the equation from values of E′ at various shorter spans. Moduli at infinite span E∞″ were also calculated by extrapolation from E′ at various spans, and the E∞″ of a width and of a material were compared with one another. The results show that the equation is a convenient and adequate means of estimating the characteristic modulus of elasticity of the specimen.
Paper ID: CTR10724J