Sheet Metal Forming Research in Japan

Research activities and their results on sheet metal forming in Japan are introduced with emphasis on the mechanics of sheet metal press-forming. Based on the governing deformation mechanisms and the characteristics of forming limits, sheet metal press-forming processes are classified into deep drawing, bulging, stretch flange forming, and bending. According to this classification, formability and its testing can systematically be evaluated with the aid of the analysis of process mechanics. For the stress and strain analyses, the method of calculation is well established and the use of a computer reveals the detail stress and strain distributions in the process. A basic problem in high energy rate processes is the mechanical behavior of materials at high strain rates, and the deformation of sheet metals in high-speed tension test is discussed. There are many problems still left for the future. A few of these are the conditions of instability and fracture, the effect of anisotropy, the analysis considering the stress and strain variations in the thickness direction, formabilities, the properties of materials at high strain rates, tool wear, and tool deformations.