lastPost

Material Modeling and Structural Mechanics

Material Modeling and Structural Mechanics


Material Modeling and Structural Mechanics



Common engineering materials reach in many applications their limits and new developments are required to fulfil increasing demands on engineering materials. The performance of materials can be increased by combining different materials to achieve better properties than a single constituent or by shaping the material or constituents in a specific structure. The interaction between material and structure may arise on different length scales, such as micro-, meso- or macroscale, and offers possible applications in quite diverse fields.

Abstract The primary purpose of this study is the development of a method for the numerical homogenization of the nonlinear creep properties of unidirectionally reinforced fiber composites. The constitutive relations for a homogeneous material, equivalent to composite, are based on the hypothesis of the existence of a potential for the strain rates of steady-state creep. The eneralization of the power-law dependence of the strain rate on stresses for the case of a complex stress state is achieved by introduction of an equivalent stress using a 4th rank tensor. 

The structure of this
tensor allows to take into account the required symmetry class for a particular form of fiber packing. The homogenization procedure is based on micromechanical analysis of a representative composite volume. A technique for the numerical simulation of physical experiments necessary for the identification of the material parameters of the theoretical model is proposed. A series of numerical calculations by the finite element method in the ANSYS software for a boron-aluminum composite has been carried out.


Composite materials are increasingly used in various fields of modern technology due to the high ratio of strength and stiffness to weight, the possibility of creating materials with the required anisotropy of properties, and good manufacturability (Altenbach et al., 2003, 2018). In engineering applications, composite structures are often subjected to stresses for a long time, which can lead to the development of creep deformations. The temperature range at which creep appears is very wide, from room temperature for composites with a polymer matrix, up to 2000◦C for carbon-carbon composites. Consideration of creep and stress relaxation in the design of structures is impossible without the development of rheological models (Reiner, 1969; Palmov, 1998) of composite materials. The relevance of such studies has led to a significant amount of recent publications devoted to various aspects of this problem.


DOWNLOAD :- HERE

Comments
No comments
Post a Comment



    Reading Mode :
    Font Size
    +
    16
    -
    lines height
    +
    2
    -