Development of techniques using finite element and meshless methods for the simulation of piercing

Abstract

Finite element analysis modelling of sheet metal stamping is an important step in the design of tooling and process parameters. One of the critical measurements to determine the effectiveness of a numerical model is its capability of accurately predicting failure modes. To be able to make accurate predictions of deformation, tool force, blank design, etc computer simulation is almost necessary. In the automotive industry the tooling design can now be made by computer and analysed with FEA, and the amount of prototypes required for qualifying a design before manufacturing commences is greatly reduced. Tool design is a specialized phase of tool engineering. While there are many diecutting operation, some of which are very complex, they can all be reduce to plain blanking , piercing, lancing, cutting off and parting, notching, shaving and trimming. The cutting action that occurs in the piercing is quite similar to that of the chip formation ahead of a cutting tool. The punch contact the material supported by the die and a pressure builds up occurs, When the elastic limit of the work material is the exceeded the material begins to flow plastically (plastic deformation). It is often impractical to pierce holes while forming, or before forming because they would become distorted in the forming operation. The aim of the research is to develop techniques that would reduce the amount time spent during the tool qualifying stage. By accurately setting a finite element simulation that closely matches the experimental or real-life situation we can great understand the material behaviour and properties before tool designing phase commences. In this analysis, during the piercing process of the drainage hole for a shock absorber seat, there is visible material tearing (on the neck) which as a result the component is rejected. This results in material wastage, and prolonged cycle time since the operation has to be now done separately at a different workstation.