The Limit Drawing Ratio (LDR) in the deep drawing process is bounded by a certain limit beyond which rupture will ensue. Among the parameters that affect this limit are process parameters: blank temperature and strain rate. In this work we present a new criterion to determine the critical strain (onset of diffuse instability) as a function of temperature and strain rate dynamic changes. Further on, we show how to incorporate this criterion into the process model and how the process can be affected by controlling these process parameters in-situ. The benefits of this criterion are examined via parametric analysis of the solution and through experimental results in deep drawing of Magnesium AZ31. A clear consequence of the proposed criterion is that changes in material properties such as strain hardening and strain rate sensitivity can be controlled.
| Number of Pages : | 6 |
| Published : | 11/01/2000 |
