Nobuo Hatanaka

Numerical Investigation of Flexural Properties of Sheet Metals Subjected to Embossing and Restoration Process

In this study, numerical simulations of flexural tests of sheet metals subjected to embossing and restoration process are carried out using LS-DYNA3D. Several models are created varying the number, position, and pitch of the emboss or restoration points. The emboss height and sheet thickness are also varied. Results show that improvement in rigidity of sheet metals can be optimized by taking into considerations several parameters as discussed in this paper.

Deep drawing of square cup with airtight using Developed blank of aluminum sheet in combination with friction stir welding

In the conventional drawing, it is difficult to make square cups taller than the length of the straight side of a punch in only one stage of drawing. The authors have proposed a new drawing method. In this method, the flange portion of a new blank is divided into four elements. Therefore, the drawing resistance of the blank material can be reduced considerably. However, the drawn cup has seams in the side walls. To make an airtight cup, the seams must be joined. A method of forming deep cups with airtight seams by using a Developed blank is proposed. The blank is drawn using a punch, while simultaneously performing friction stir welding (FSW). The FSW rotation probe placed on the flange contact point generates friction heat that joins the seam parts of the side walls. The production of a very deep airtight cup in a single process was successfully accomplished using the proposed method. In this study, the joint strength of the seam part was examined by tensile testing. The variation in the sheet thickness distribution due to processing was also investigated. The results showed that the joint properties are improved by offsetting the tool from the flange contact point. (Received August 29, 2014 Accepted November 20, 2014)