Numerical investigation on forming behavior of friction stir tailor welded blanks (FSTWBs) during single-point incremental forming (SPIF) process

Abstract

Tailor welded blank (TWB) is a product which is developed by joining two or more than two materials having same/different thickness and/or properties before any forming process. The method to join the materials can be any of the conventional or advanced methods. TWB offers advantages like overall weight and cost reduction in a product. Despite of such advantages, the application of TWBs is partially resisted by the disadvantages associated with it like formability reduction and weld line movement during the forming operations. A lot of effort has been done in order to overcome the mentioned limitations of the TWBs. However, for homogeneous blank, single-point incremental forming (SPIF) results in better formability so in present work, the attempt has been made to study the forming behavior of TWB during the SPIF process. In this work, the effect of TWB material parameters like yield strength ratio, thickness ratio, strength coefficient ratio and strain index ratio of the parent materials has been investigated on the weld line movement and % thinning of the blank through finite element analysis. In order to perform the numerical analysis, ABAQUS/Explicit was used. Using SPIF, round cup geometry is formed from a flat TWB and effect of different initial positions of tool is investigated. It has been found that when the forming process is started from the weld and tool is travelled toward strong material of the blank, it leads to the minimum thinning, weld line shift and plastic equivalent strain (PEEQ).