Material Model

Selective laser melting (SLM) is an additive technology that allows for the production of precisely designed complex structures for energy absorbing applications from a wide range of metallic materials. Geometrical imperfections of the SLM fabricated lattice structures, which form one of the many thin struts, can lead to a great difference in prediction of their behavior. This article deals with the prediction of lattice structure mechanical properties under dynamic loading using finite element method (FEA) with inclusion of geometrical imperfections of the SLM process. Such properties are necessary to know especially for the application of SLM fabricated lattice structures in automotive or aerospace industries. Four types of specimens from AlSi10Mg alloy powder material were manufactured using SLM for quasi-static mechanical testing and determination of lattice structure mechanical properties for the FEA material model, for optical measurement of geometrical accuracy, and for low-v...

As well as acting as a moderator and reflector, graphite is used as a structural component in many gas-cooled fission nuclear reactors. Therefore the ability to predict the structural integrity of the many graphite components which make up a graphite reactor core is important in safety case assessments and reactor core life prediction. This involves the prediction of the service

Geometrical models needed for finite element discretization of plain-weave fabric-reinforced composites are developed from measurements taken on photomicrographs of single lamina and laminated composites. Then, a meso-level damage model is implemented into ANSYS as a user-defined material model for predicting the non-linear behavior of plain-weave reinforced laminates under tensile loading. The damage model is validated for the tensile response of T300/5208 laminate for four configurations, [10/−10]2s, [0/45/−45/90]s, [30/−30]2s and [45/−45]2s. Then, the damage behavior of plain-weave fabric-reinforced laminates is analyzed using the proposed damage model in the context of the finite element method. The modes of continuum damage are identified from the analysis. Comparisons with experimental data are provided in order to support validity of the proposed models.

This researching deals with the material models used by Finite Elements software to predict the behavior of the stress and strain of hyperelastic materials. The mechanical test needed to describe the behavior of these materials is mentioned. Here shown are the stress-strain curvesbehaviors during the application of repetitive loads. Finally, this is explaining how to determine the values of

In analysis and design of structures subjected to earthquakes, the cyclic and dynamic nature of the response leads to complications. Material models need to account for cyclic plasticity, including deterioration and eventual failure due to low-cycle fatigue. A cyclic damage plasticity model MAT_DAMAGE_3 (MAT_153, LSTC 2007) is implemented to combine Armstrong-Frederick/Chaboche nonlinear kinematic hardening, isotropic hardening, and Lemaitre isotropic damage

Rubbery polymers are subjected to severe environmental conditions under service. As a consequence of various ageing mechanisms, the outer surface of rubber components hardens in time and cracking occurs as a result of combined mechanical and chemical processes. Conventional phenomenological hyperelastic constitutive models do not account for material softening. Consequently, the stored energy and stresses tend to infinity as stretch increases. In this contribution, a network alteration for the ageing mechanism of rubber-like materials is introduced along with a micromolecular description of material failure. The proposed micro-continuum material model is based on a serial construction of a Langevin-type spring representing the energy storage owing to conformational changes induced by deformation, to a bond potential representing the energy stored in the polymer chain due to the interatomic displacement. For the representation of the micro–macro transition, the non-affine kinematics of the micro-sphere model is used. The Morse potential is utilized for the interatomic bond, which describes the energetic contribution to rubber-like materials and governs the failure of the polymer chain in terms of bond rupture. A novel numerical scheme for the FE implementation of the proposed model is demonstrated. The hardening phenomenon as a result of diffusion limited oxidation of rubber is explained by the principle of mass conservation which dictates simultaneous modulus hardening along with decrease in ultimate stretch observed in aged rubbery polymers.