Reliability-based analysis of a stretch-bending process for aluminium extrusions

摘要

The paper presents reliability analyses of a plastic forming process. Stretch-bending of extruded aluminium square hollow sections was studied through finite element analysis. The profiles were axially fixed and given a specified curvature by means of a bending die. Important response parameters in stretch-bending of extruded profiles are flange sagging and elastic springback. The sensitivity of the predicted response parameters was investigated with respect to variations in the material properties of the aluminium alloy, i.e. yield stress, strain hardening and plastic anisotropy. The material parameters were modelled as random variables with given statistical properties. The probability of the response parameters staying within specified limits could then be calculated by means of response surface methods and FORM/SORM. Finally, the consequences of the specified response limits on allowable variations of the material properties were established. The paper shows how reliability-based methods can be used to establish relations between the variation of model parameters (e.g. material properties, cross-sectional geometry and process parameters) and the resulting variation of variation of characteristic response parameters for a given forming process.