Shape optimisation of preform design for precision close‐die forging

Preform design is an essential stage in forging especially for parts with complex shapes. In this paper, based on the evolutionary structural optimisation (ESO) concept, a topological optimisation method is developed for preform design. In this method, a new criterion for element elimination and addition on the workpiece boundary surfaces is proposed to optimise material distribution. To improve the quality of the boundary after element elimination, a boundary smoothing technique is developed using B‐spline curve approximation. The developed methods are programmed using C# code and integrated with DEFORM 2D software package. Two 2D case problems including forging of an aerofoil shape and forging of rail wheel are evaluated using the developed method. The results suggest that the developed topology optimisation method is an efficient approach for preform design optimisation.