A flexible tool design and integrated modelling techniques for springback compensation in creep-age forming

Abstract

This thesis presents the development of ad-hoc experimental and integrated modelling techniques for springback compensation in creep-age forming (CAF). A test programme is presented which describes the material and workpiece information and the test plans for the experimental evaluation of the creep-ageing and springback behaviour of aluminium alloy 7B04-T651 under 115 oC. Experimental results from the creep-ageing and tensile tests were used to determine a CAF material model for the alloy. A flexible tool design has been proposed and a laboratory-scale prototype has been delivered and used to perform the CAF tests in this research. The determined CAF material model and geometry of the flexible tool design were treated as input and used to construct a CAF process model using finite element (FE) method. Comparisons between final deflections of FE-simulated and experimentally formed plates validated the springback predictive ability of the FE process model. The model was eventually employed to model springback-compensated tool shapes and using the modelled tool shapes to perform CAF tests have produced formed plates that have an average 0.81±0.14 mm of maximum absolute vertical difference from target shape. CAF can now be used to produce accurately shaped panel components in a laboratory environment using the equipment and techniques developed in this research.