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This paper addresses the problem encountered in the quantitative description of arrangements and correlations in unidirectionally reinforced composite materials. Both topological and second-order statistical measures are related to the stress variability that exists under transverse loading conditions. The main attention is paid to the variability of interfacial maximal radial stresses which are primary sources of an interfacial debonding. Correlation measures have been suggested for global, as well as local, correlations. It is shown that a further improvement of the local correlation measures is necessary if it is going to be used as a diagnostic tool to pinpoint most loaded, local areas of the microstructure.

Experimental and analytical techniques are employed in the present study to identify a damage parameter with the acoustic emission signature in woven glass fiber reinforced composite under tensile loading. The damage parameter is estimated by the use of stereological methods and its relation to acoustic emission monitoring is enlighted.

A general constitutive equation for creep deformation is presented based upon the concept of tensorial internal variables. The consequences of the theory of tensor functions representation are discussed with respect to the evolution equations. In a particular case of steady evolution of internal variables the governing equation for the secondary creep rate is derived in terms of a scalar inelastic potential. The material parameters required to characterize the stationary creep behaviour of the orthotropic composite are obtained from the unidirectional tension creep tests performed on a glass woven fabric xylok composite. Further check on the theory is made for the bidirectionally loaded specimens.

A general constitutive equation for steady-state creep deformation is presented based on the concept of dissipation potential. The material parameters required to characterize the stationary static creep behaviour of an orthotropic composite are obtained from the unidirectional tension creep tests and biaxial tension—shear creep tests performed on a glass—xylok woven fabric composite. If an oscillatory load is superimposed on a sustained loading the steady creep rate changes depending on the oscillatory frequency. This effect is shown by conducting biaxial tests with the shear force possessing both static and dynamic components. In order to describe the alteration of the creep rate in the presence of dynamic fluctuations the static dissipation potential is modified to take account of the frequency effects.

Atomistic-based simulations such as molecular mechanics (MM), molecular dynamics (MD), and Monte Carlo-based methods (MC) have come into wide use for material design. Using these atomistic simulation tools, we can analyze molecular structure on the scale of 0.1–10 nm. However, difficulty arises concerning limitations of the time and length scale involved in the simulation, particularly when nanoparticles are involved in the system. Although a possible molecular structure can be simulated by the atom-based simulations, it is less realistic to predict the mesoscopic structure with nanoparticles defined on the scale of 100–1000 nm. For the morphology on these scales, mesoscopic simulations are available as alternatives to atomistic simulations allowing to bridge the gap between atomistic and macroscopic simulations for an effective material design. In this contribution, a hierarchical procedure for bridging the gap between atomistic and macroscopic (FEM) modeling passing through mesoscopic simulations will be presented and applications of systems with nanoparticles will be discussed.