Thickness Variation, A Wide Sheet Of Plastic Bending And Forming

The thin out phenomenon of bending metal sheet is well-known. When the metal sheet is processed by bending forming, it is necessary to estimate accurately the influence of the thin out of the metal sheet to the size of blank and precision of the product. For a long time, about the problem that "the thin out phenomenon of the bending metal sheet" is limited in experimental study and lack the theoretical foundation. The only theory had presented by Hill R. in 1950, its result conclude that "the ideal plasticity metal sheet is non-thin out along the thicknees direction." But this theory is contradictory with the productive actuality.In order to set up the correct theory for thin out phenomenon of the bending metal sheet, A series of new theoretical solution developmented by author is presented in this paper. These theoredical solutions are based on following two assumptions: 1. the bending sheet keep circular arc permanently. 2. the cross section keep flat and straightly. The theoretical solutions contain two method of solving: proportional method and coincident method. Utilize two method ,the thin out of bending metal sheet with ideal plasticity and linear hardening character are analyzed separately, and the formula calculated the variation of the radius of out side suface, thickness of the sheet, thin out coefficient and the inward removal of neutral layer with the radius of the inside suface of bending sheet are derived.In order to verify the rationality of this theoretical research, the theoretical solution is calculated through the instance. The result of theoretical calculation is compared with the experimental data that is used extensively in production reality. The result is shown that both the theoretical solution and the experimental data are very close. Thus the rationality of this research and exactness of calculation are verified.A series of achievements of this research were published successively in publications:《Journal of plasticity engineering》,《Metal forming technology》,《Die and mould technology》,《Mechanics and practise》and《Forging and stamping technology》,etc, and was searched by the U.S.A. publication《Engineering Idex》.(Accession number: 04318296888)...