Plastic deformation in flat-section band clamps

Previous work on the elastic deformation of flat-section band clamps has been extended to account for plastic deformation of the band material. Both finite element analysis using a multilinear plastic model and a classical approach using a continuous plastic equation are reported. The excellent agreement between the results of these two approaches provides a high level of confidence in the models. The finite element approach was found to be extremely time consuming owing to the combination of changing contact non-linearity and material nonlinearity. The classical approach provided a much faster solution method when used with the iteration schemes proposed here. The classical method of analysis was used to determine the response to a range of conditions. This analysis showed that there might be some advantage in driving flat-section band clamps into the partially plastic state. In this state the coefficient of friction has far less impact on the variation in circumferential stress, and hence radial clamping force, around the band.