Abstract
A new technique is presented which permits to obtain the relative critical strengths of the slip and twinning systems in polycrystalline materials. It consists in an experimental and a simulation part. In the experience, slip line analysis and grain orientation measurements are carried out and the operating slip and twinning systems are identified in each selected grain. In the subsequent simulations, a crystal plasticity code is used to modelise the plastic behaviour, especially, the slip activity of the grains. The relative crss values of the slip systems are then varied and the simulations are repeated iteratively until the experimental slip activity is reproduced with the very same combination of crss for all the grains. An application is presented for a Titanium alloy (Ti40).