On the numerical modelling of the multiphysics self piercing riveting process based on the finite element technique

The development of reliable numerical models permits to investigate the manufacturing processes with very low incremental costs or prototyping efforts hence it provides a relevant help in process optimisation and gives great opportunity for making maximum use of sparse process data [Shercliff HR, Lovatt AM. Selection of manufacturing process in design and the role of process modelling. Prog Mater Sci 2001;46:429–59]. Among others the metal forming processes have heavily benefited from the finite element numerical computing technology [Chenot JL, Massoni E. Finite element modelling and control of new metal forming processes. Int J Machine Tool Manuf 2006;46:1194–200]. The self piercing riveting (SPR) is a cold forming process which creates a strong mechanical interlock between two or more sheets by means of a semi-tubular rivet, which, pressed by a punch, pierces the upper sheet and flares into the bottom one. It is governed by complex multiphysics phenomena whose governing equations can be resolved using the finite element method. In this paper all the governing equations are fully reported along with the mathematics of the resolving method needed for setting up and simulate a finite element model of the self piercing riveting of an aluminium alloy. A case study of the SPR of two sheets of the 6060T4 aluminium alloy using a steel rivet was investigated. The calculations were performed using the LsDyna finite element commercial code. The problems encountered and the solutions applied for the preparation of the model and the run of the calculation were presented and discussed. The obtained results were validated by comparison with data coming from a laboratory experiment.