A mesh objective crack band model is implemented in the generalized method of cells (GMC) micromechanics model to predict failure of a composite repeating unit cell (RUC). The micromechanics calculations are achieved using the MAC/GMC core engine within the ImMAC suite of micromechanics codes, developed at the NASA Glenn Research Center. The microscale RUC is linked to a macroscale Abaqus/Stand...

Much of the previous work in developing analytical models for high performance composite materials has focused on representations of the heterogeneous medium as a homogenous, anisotropic continuum. The development of the equivalent properties of the homogenous medium from the geometry of the microstructure and the fiber and matrix properties has been come to be known as “micromechanics” (Daniel...

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Integrated computational materials engineering (ICME) is a useful approach for tailoring the performance of a material. For fiber-reinforced composites, not only do the properties of the constituents of the composite affect the performance, but so does the architecture (or microstructure) of the constituents. The generalized method of cells is demonstrated to be a viable micromechanics tool for...

We model trabecular bone as a nanocomposite material with hierarchical structure and predict its elastic properties at different structural scales. The analysis involves a bottom-up multi-scale approach, starting with nanoscale (mineralized collagen fibril) and moving up the scales to sub-microscale (single lamella), microscale (single trabecula) and mesoscale (trabecular bone) levels. Continuu...

The response of a neo-Hookean fiber composite undergoing finite out-of-plane shear deformation is examined. To this end an explicit close form solution for the out-of-plane shear response of a cylindrical composite element is introduced. We find that the overall response of the cylindrical composite element can be characterized by a fictitious homogeneous neo-Hookean material. Accordingly, this...

A continuum-based elastic micromechanics model is developed for silica nanoparticle/polyimide composites with various nanoparticle/polyimide interfacial treatments. The model incorporates the molecular structures of the nanoparticle, polyimide, and interfacial regions, which are determined using a molecular modeling method that involves coarse-grained and reversemapping techniques. The micromec...

The Halpin-Tsai equations are based upon the “selfconsistent micromechanics method” developed by Hill. Hermans eniplovetf this model to obtain a solution in terms of Hill’s “reduced moduli”. Halpin and ’Tsai have reduced Hernians’ solution to a simpler analytical form arid extended its use for a variety of filament geometries. The development of these niicromechanics relationships, which form t...

This paper discusses the use of fracture mechanics for the microstructure tailoring of a fiber reinforced Engineered Cementitious Composite (ECC) to achieve extreme tensile ductility at the composite scale. It demonstrates that fracture mechanics applied to control fracture phenomena at the micro and meso material scales can lead to suppression of fracture failure at the macro structural scale....

The aggregate in an asphalt mixture is coated with mastic consisting of bitumen (dilute phase) and filler (particulates phase). interaction packing plays important role the properties mastics. micromechanics models from composite rheology can be used to predict stiffening effect a suspension. In this research, fillers was investigated based on mastic. frequency sweep tests dynamic shear rheomet...