Publication: A procedure for determining the true stress-strain curve over a large range of strains using finite element analysis for ductile materials
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Date
2017
Authors
Lakshmandas Kuna Sakar
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Abstract
The use of ductile materials in engineering applications are of monstrous proportions. They are used at a great deal within the manufacturing and transportation sectors of the world. The state at which these materials deform provide an insight at the workability of these materials. In order to understand the material, a comprehensive study on the deformation of material is required to fully actualize a certain material's workability. The simplest way to do so is the tensile test. The tensile test is a uniaxial test that simply works by measuring the force required to elongate a material by a specific length. From the tensile test, it is possible to obtain both engineering and true stress-strains. However, there comes a point of inconvenience as the material is stretched. Up till Ultimate Tensile Strength (UTS), the material obeys the uniaxiality of the tensile test and the material continues to stretch in a uniform manner. However, beyond the point of UTS, the material begins to neck. Necking occurs when the increase in strain hardening of a material is unable to compensate for the cross sectional area reduction of the material. With necking brings about complex stress components which starts to resonate to various fields of motion. This phenomena is termed stress triaxility. Hence the unvarying degree of freedom in the tensile test is considered to be obsolete due to stress triaxility. The tensile test is said to be inaccurate as it is only viable up till UTS. In this respect, this study sets out to correct the true tensile profile of ductile materials beyond UTS taking DP 600 High Strain Steel as the material probed in this study. For this purpose, a standard 2mm-thick sheet metal specimen are performed to establish a corrected tensile profile for this material. A experimental-numerical method is suggested in this study whereby detailed Finite Element simulation is done to replicate the events of a conventional tensile test. The true tensile profile is then obtain via a reverse engineering manner where by the true stress-strains of the material is made the input and the load-displacement of the material, the output. Iterations are done by altering the input values of the simulation until a load-displacement bend that suits the original experimental load-displacement data is obtained. This in return generates a new and corrected true tensile profile for the region beyond UTS and provides a definitive look at fracture mechanics.
Description
TA460.L34 2017
Keywords
Metals