A new approach for the determination of the linear elastic modulus from uniaxial tensile tests of sheet metals (original) (raw)
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Aluminium is one of the most used metals in today's industry, having properties of strength, durability, conductivity, lightness, and corrosion resistance. Sheet metal forming is a process that widely used and costly manufacturing process. A materials problem is one of selecting the right material from the many thousands that are available. Aluminium has a low density, good corrosion resistance and relatively cheap. Aluminium sheet becomes favourable comparing with steel regards to some improvement at the designs. Automotive parts and products are used wide range of these materials included bumpers, doors, bars, seat frames and roof panels. Nonlinear analysis is much more complicated than simple linear analysis because it is required many variables such as changes in geometry, permanent deformations, structural cracks and buckling. This paper was carried out to study the elastic-plastic analysis of sheet metal forming using finite element method. LUSAS simulation was carried out to understanding the behaviour of aluminium sheet and accurate results of this process. Axi-symmetry and plain strain element mesh were used to model and study this metal. Deep analysis was carried out and the effect of geometry of sheet metal forming process has been studied. A good agreement between the load and the displacement test was obtained that verified the program.
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This work consists of determining the plastic strain value undergone by a material during a forming process using the instrumented indentation technique (IIT). A deep drawing steel DC01 is characterized using tensile, shear and indentation tests. The plastic strain value undergone by this steel during uniaxial tensile tests is determined by indentation. The results show that, the identification from IIT doesn’t lead to an accurate value of the plastic strain if the assumption that the hardening law follows Hollomon law is used. By using a F.E. method, it is shown that using a Voce hardening law improves significantly the identification of the hardening law of a pre-deformed material. Using this type of hardening law coupled to a methodology based on the IIT leads to an accurate determination of the hardening law of a pre-deformed material. Consequently, this will allow determining the plastic strain value and the springback elastic strain value of a material after a mechanical formi...
Journal of Japan Institute of Light Metals
This paper proposes a material modeling methodology of sheet metals using a numerical biaxial tensile test based on the crystal plasticity finite element (CPFE) method and the mathematical homogenization method. To demonstrate the feasibility of the proposed methodology, the biaxial tensile deformation behavior of 5182 aluminum alloy sheet was predicted by the numerical biaxial tensile tests of the sheet. The stress-strain curves and the shapes of the contours of plastic work calculated by the numerical biaxial tensile tests were quantitatively verified by the experimental biaxial tensile test using the cruciform specimen. Parameters of the Yld2000-2d yield function were identified using the results of experimental and numerical biaxial tensile tests. For comparison, von Mises s and Hill s yield functions were identified using the experimental data. To elucidate the effects of the yield functions on the accuracy of sheet metal forming simulation, finite element simulations of hydraulic bulge forming were performed using the identified yield functions. The simulation results demonstrated that the forming simulation using the Yld2000-2d yield function identified by the numerical biaxial tensile tests showed better accuracy than that of the Mises s and Hill s yield functions and was comparable to that of the Yld2000-2d yield function calibrated experimentally.
International Journal of Mechanical Sciences, 2013
This paper presents an extension of the classical elastic law. The main objective of this new law is to represent linear and non-linear behaviour for computational metal forming purposes. The extension of the model is built by means of a stress-strain relationship given by an integral equation, its kernel characterising the mentioned complex behaviour. A specific application is presented for a TRIP 700 steel. Using experimental data obtained from elastoplasticity tests, the kernel of the model is formulated by means of a specific computational curve fitting procedure. The excellent agreement between experimental data and fitted model results validates the proposed model. Furthermore, a V-bending test is simulated, springback being represented by means of three different models: elastic, linear elastic with variable elastic modulus and extended elastic models. From the results differences between extended elastic law and the classical one are around 50%.
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A new technique that can determine the elastic-plastic properties of metallic materials using an instrumented indentation testing and iterative finite element (FE) simulations is proposed. This non-destructive technique can be applied to isotropic, additively manufactured, and/or surface treated metallic components of various scale. Currently, the measurement of material properties using the instrumented microor nanoindentation test is limited to the elastic modulus and surface hardness. A number of experimental and numerical approaches have been suggested for prediction of monotonic properties of metallic materials including yield strength, strain hardening parameters, ultimate strength, and fracture toughness. However, the past efforts to measure the stress-strain behavior using a single instrumented indentation test were not successful because there is no straightforward correlation between forcedisplacement relation and the elastic-plastic relation. In this study, both experimen...