Plastic Collapse of Cylinders Under Constrained Conditions

Abstract

This paper deals with an experimental methodology of the large deformation of cylinders under constrained sides and end conditions. A specific arrangement of two geometrically identical cylinders compressed laterally is studied under different quasi-static strain rates. Several tests are performed using two different structural situations. In the first case, the two cylinders are made from superplastic tin-lead alloy, while in the second case, one cylinder is made from superplastic and the other from steel. Different cylindrical geometries are investigated having the same cross sectional area with different ratios of inner to outer diameter (di/do). The load-deflection curves are recorded and then the energy absorbed per unit volume is determined. The experiments show obviously the remarkable sensitivity of the utilized superplastic to the strain rate in the range of 10−5/s–10−3/s. A two-dimensional finite element simulation is also conducted describing the collapse behavior of these cylindrical geometries in both structural cases under different strain rates. A confrontation with experimental observation shows that the predictions describe fairly well the experiments.