Using Forming Limit Curve ( Flc ) Essay

1684 Words Nov 3rd, 2016 7 Pages
1. Introduction
Polycrystalline materials dominate industrial and technological applications due to their ubiquitous existence, low-cost and ease of manufacturing. During the sheet metal operations, e.g. bending, stamping, drawing and stretching, among the various possible modes of failure, such as wrinkling, scoring, the tearing of a polycrystalline sheet metal is the most common, resulting from an uneven or exorbitant amount of plastic deformation forming a localized neck and therefore limiting the formability of the polycrystalline sheet metal. In the sheet-metal forming industry, it is therefore, of high importance that the failure of metal sheets due to localized necking must be analyzed. In 1963, a breakthrough in formability assessment came, Keeler, 1961 introduced the concept of forming limit curve (FLC) also known as the forming limit diagram (FLD) that provide an approximation of how close the material is to neck and has been extensively used thereafter to quantify the formability of a sheet metal. To obtain the FLD experimentally, the surface of the blank of a sheet metal is printed using a regular grid and is then subjected to stretching using a hemispherical punch, the regular grid deforms and the principal strains (major strain and minor strain) at localization are calculated using a high resolution digital image correlation (DIC) technique. Depending upon the modes of deformation varying from uniaxial tension to plane strain tension on the left side of FLD and…

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