A critical analysis of plane shear tests under quasi-static and impact loading

This paper presents an extensive investigation of the real testing conditions of plane shear tests under quasi-static as well as impact loading. In particular, it aims at analyzing the role played by the empirical corrective coefficients commonly used in this kind of tests. For this purpose, a complete numerical model including not only specimen but also clamping device is built. Compared with usual simulations of only a shear specimen used to establish these corrective coefficients, the proposed complete numerical model permits to evaluate the influence of clamping device on the distribution of stress and strain fields. It shows that there are only limited effects under static loading, except for the early stage of loading (elastic part) where the stiffness of clamping device has to be taken into account. Under dynamic loading, a similar conclusion as the static case has been made. However, the transient effect due to the wave propagation within clamping pieces is rather important before an equilibrium state is reached. Numerical results indicate also that the shear loading on the specimen is mainly guided by the compressive wave in the massive clamping pieces, and the shear wave propagation inside the shear area is negligible. Besides, the way to calculate the equivalent strain from experimentally measured displacement is discussed. Eulerian cumulated strain, which is the default large strain definition in most commercial codes, should be used instead of the idealized small strain shear assumption. Finally, this work indicates that when the average value of equivalent stress in the whole shear area and cumulated Eulerian strain are used, commonly used corrective coefficients are no longer needed. (C) 2014 Elsevier Ltd. All rights reserved.