tailieunhanh - Analytical study for deformability of laminated sheet metal

While a freestanding high-strength sheet metal subject to tension will rupture at a small strain, it is anticipated that lamination with a ductile sheet metal will retard this instability to an extent that depends on the relative thickness, the relative stiffness, and the hardening exponent of the ductile sheet. This paper presents an analytical study for the deformability of such laminate within the context of necking instability. Laminates of high-strength sheet metal and ductile lowstrength sheet metal are studied assuming: (1) sheets are fully bonded; and (2) metals obey the power law material model. The effect of hardening exponent, volume fraction and relative stiffness of the ductile component has been studied. In addition, stability of both uniform and nonuniform deformations has been investigated under plane strain condition. The results have shown the retardation of the high-strength layer instability by lamination with the ductile layer. This has been achieved through controlling the aforementioned key parameters of the ductile component, while the laminate exhibits marked enhancement in strength–ductility combination that is essential for metal forming applications. | Journal of Advanced Research 2013 4 83-92 Cairo University Journal of Advanced Research ORIGINAL ARTICLE Analytical study for deformability of laminated sheet metal Mohammed H. Serror Department of Structural Engineering Faculty of Engineering Cairo University Egypt Received 11 October 2011 revised 24 December 2011 accepted 23 January 2012 Available online 3 March 2012 KEYWORDS Sheet metal laminate Necking instability Deformability Power-law model Abstract While a freestanding high-strength sheet metal subject to tension will rupture at a small strain it is anticipated that lamination with a ductile sheet metal will retard this instability to an extent that depends on the relative thickness the relative stiffness and the hardening exponent of the ductile sheet. This paper presents an analytical study for the deformability of such laminate within the context of necking instability. Laminates of high-strength sheet metal and ductile low-strength sheet metal are studied assuming 1 sheets are fully bonded and 2 metals obey the power law material model. The effect of hardening exponent volume fraction and relative stiffness of the ductile component has been studied. In addition stability of both uniform and nonuniform deformations has been investigated under plane strain condition. The results have shown the retardation of the high-strength layer instability by lamination with the ductile layer. This has been achieved through controlling the aforementioned key parameters of the ductile component while the laminate exhibits marked enhancement in strength-ductility combination that is essential for metal forming applications. 2012 Cairo University. Production and hosting by Elsevier . All rights reserved. Introduction There has been a strong demand for high-strength steel having an exceptionally good strength-ductility combination. For conventional steel in bulk form however there exists a clear Tel. 20 2 26343729 fax 20 2 26343849. E-mail address .