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The purpose of this paper is to investigate of interphasial effects, including temperature dependency, within fiber reinforced polymers on the overall composite behavior. Providing theoretical and numerical approaches in terms of a consistent thermomechanical finite element method framework are further goals of this research.

Starting points for achieving the aims of this research are the partial differential equations describing the evolution of the displacements and temperature within a continuum mechanical setting. Based on the continuous formulation of a thermomechanical equilibrium, constitutive equations are derived, accounting for the modeling of fiber reinforced thermosets and thermoplastics, respectively. The numerical solutions of different initial boundary value problems are obtained by a consistent implementation of the proposed formulations into a finite element framework.

The successful theoretical formulation and numerical modeling of the thermoinelastic matrix materials as well as the thermomechanical treatment of the composite interphase (IP) are demonstrated for an epoxy/glass system. The influence of the IP on the overall composite behavior is successfully investigated and concluded as a further aspect.

A thermomechanical material model, suitable for finite thermoinelasticity of thermosets and thermoplastics is introduced and implemented into a novel kinematic framework in context of the inelastic deformation evolution. The gradually changing material properties between the matrix and the fiber of a composite are continuously formulated and numerically processed, in order to achieve an efficient and realistic approach to model fiber reinforced composites.

The purpose of this work is to apply a recently proposed constitutive model for mechanically induced martensitic transformations to the prediction of transformation loci. Additionally, this study aims to elucidate if a stress-assisted criterion can account for transformations in the so-called strain-induced regime.

The model is derived by generalising the stress-based criterion of Patel and Cohen (1953), relying on lattice information obtained using the Phenomenological Theory of Martensite Crystallography. Transformation multipliers (cf. plastic multipliers) are introduced, from which the martensite volume fraction evolution ensues. The associated transformation functions provide a variant selection mechanism. Austenite plasticity follows a classical single crystal formulation, to account for transformations in the strain-induced regime. The resulting model is incorporated into a fully implicit RVE-based computational homogenisation finite element code.

Results show good agreement with experimental data for a meta-stable austenitic stainless steel. In particular, the transformation locus is well reproduced, even in a material with considerable slip plasticity at the martensite onset, corroborating the hypothesis that an energy-based criterion can account for transformations in both stress-assisted and strain-induced regimes.

A recently developed constitutive model for mechanically induced martensitic transformations is further assessed and validated. Its formulation is fundamentally based on a physical metallurgical mechanism and derived in a thermodynamically consistent way, inheriting a consistent mechanical dissipation. This model draws on a reduced number of phenomenological elements and is a step towards the fully predictive modelling of materials that exhibit such phenomena.

The purpose of this paper is to deal with large deformation analysis of plane beams composed of functionally graded (FG) elastic material with a variable Poisson’s ratio.

The material is assumed to be linear elastic, with a Poisson’s ratio varying according to a power law along the thickness direction. The finite element used is a plane beam of any-order of approximation along the axis, and with four transverse enrichment schemes, which can describe constant, linear, quadratic and cubic variation of the strain along the thickness direction. Regarding the constitutive law, five materials are adopted: two homogeneous limiting cases, and three intermediate FG cases. The effect of both finite element kinematics and distribution of Poisson’s ratio on the mechanical response of a cantilever is investigated.

In accordance with the scientific literature, the second scheme, in which the transverse strain is linearly variable, is sufficient for homogeneous long (or thin) beams under bending. However, for FG short (or moderate thick) beams, the third scheme, in which the transverse strain variation is quadratic, is needed for a reliable strain or stress distribution.

In the scientific literature, there are several studies regarding nonlinear analysis of functionally graded materials (FGMs) via finite elements, analysis of FGMs with constant Poisson’s ratio, and geometrically linear problems with gradually variable Poisson’s ratio. However, very few deal with finite element analysis of flexible beams with gradually variable Poisson’s ratio. In the present study, a reliable formulation for such beams is presented.

This paper aims to present a phenomenological model to investigate the underlying mechanism and predict the bio-inspired performance under different thermo-temporal conditions.

Flory-Rehner free-energy functions are applied to quantitatively identify the driving forces in the viscously bio-inspired response of a dynamic polymer network. Furthermore, the permeation transition equation is adopted to couple water gradient and water sorption/desorption into the free-energy function.

The results show that the influence of potential energy on deformation can be related to a stretching ratio that uniquely determines water sorption/desorption, locomotion frequency and contractile stress. Finally, by means of combining the free-energy function and Arrhenius equation, a phenomenological thermo-temporal model is developed and verified by the experimental results.

This study focuses on exploring the theoretical mechanism and significantly enhances understanding of relevant experimental features reported previously.

The outcome of this study will provide a powerful phenomenological and quantitative tool for study on shape memory effect in bio-inspired polymers.

Constant question in determination of a social system state is how to obtain a sufficient quantity of information with a small enough, manageable indicator set.

The concept is developed in a thorough analysis of strengths and weaknesses of existing approaches, and in thorough contrasting the proposed solutions with these.

The social free energy and social entropy overcome the gap between the meta‐theoretically founded quantities and indicators related to social system state description. The social free energy measures the totality of resources used for social system preservation during changes in environment. The social entropy measures the number of different realisations of a particular state.

Combination of social free energy and social entropy is on the one hand a set of quantities easily determinable from available data, and on the other hand a set of indicators intuitively connected with social system states. We relate the system social free energy and levels of organisation and adaptation. From these measures we derive the measure of social system adaptation.

The use of social free energy in describing the social system states adds a significant value in forming the small set of representative indicators. It is of importance for all researchers; theoreticians and practitioners.

The paper sets out to develop the T(x) model, based on well known principles and using the free energy of the ferromagnetic binary system as a starting point.

With the inclusion of the coercive and the intermolecular forces the model fully describes the hysteretic process for both major and minor loops, with exchange field between adjacent magnetic moments.

The paper formulates the dependence of the hysteretic system's normalised free energy on parameters such as the temperature, coercivity, other magnetic and materials properties of the ferromagnetic medium.

Experimental verification will still be needed as to the accuracy of the model and the applicability to the various magnetic materials.

The paper provides an easy mathematical and visual method to present the energy state and its variation of the magnetic materials during magnetisation, including non‐saturation conditions. It has a great value to people engaged in theoretical research in magnetism.

So far free energy calculations were only possible for major hysteresis loops. The T(x) model, as presented here, is applicable to the calculation of the free energy flow of any symmetrical minor loops as well.

In this paper a continuum description of deformable magnetized material including long‐range magnetic forces and magnetostriction is presented. Herein, magnetostriction and long‐range forces on the one hand, and magnetization and deformation on the other hand are considered simultaneously. Therefore, neither a strict distinction between the deformation due to magnetic forces and due to magnetostriction, nor a separation of the total free energy into magnetic and elastic energy is involved.

Discusses the 2‐D minimum free energy (MFE) parameter and spectral estimation method and presents an algorithm for its implementation. Notes a profound lack of results in the literature on 2‐D spectral estimation methods and on their comparison. To address this issue and to impart an overall impression of the performance of 2‐D MFE, compares results from the Levinson method, a maximum entropy method (MEM), and a hybrid method with 2‐D MFE. Points out that 2‐D MFE can provide superior spectral estimates to that produced with MEM and that, in general, MFE requires a larger area of correlation support than the hybrid method. Also notes that 2‐D MFE can provide superior spectral estimation over the 2‐D Levinson algorithm.

Shape memory alloys are a fascinating class of materials because they combine both structural and functional properties. These properties strongly depend on temperature. One consequence of this dependency yields the characteristic shape‐memory effect: shape memory alloys can recover processed reference configurations after significant plastic deformations simply upon a change of temperature. For real materials, such processes incorporate characteristic hysteresis. This paper aims at an understanding of these materials from an atomistic point of view.

2D molecular‐dynamics (MD) simulations describing a chain consisting of 32 linked Lennard‐Jones crystals are presented. The crystals consist of nested lattices of two atom species. Distinct lattice structures can be identified, interpreted as austenite and (variants of) martensite. Temperature and/or load‐induced phase transitions between these configurations are observed in MD simulations. Previously, the thermal equation of state of one isolated crystal was investigated and its phase stability was discussed in detail. In the multi‐crystal chain considered in the present paper, individual crystals contribute collectively to the thermo‐mechanical behavior of the assembly.

The paper presents the results of numerical experiments with this polycrystalline chain under strain‐, load‐ and/or temperature‐control. The results show that with the assumption of simple Lennard‐Jones potentials of interaction between atoms in individual crystals and linking these crystals allows to reproduce the features associated with the fascinating behavior of shape memory alloys, including pseudo‐plasticity, pseudo‐elasticity and the shape memory effect.

Owing to the special setup chosen, interfaces are missing between adjacent crystals in the chain assembly. The paper shows that in this situation load‐induced austenite/martensite transitions do not exhibit hysteresis in tension/compression cycles. This observation indirectly supports mesoscopic‐level work in the literature which explicitly introduces interface energy to model such hysteresis.

The purpose of this paper is to develop a progressive damage framework to predict the fatigue life of cord-reinforced rubber composite under cyclic loadings. Special attention has been paid to failure mechanisms, like cord–rubber interfacial debonding, and rubber matrix damage.

The constitutive modeling is based on the continuum damage mechanics (CDMs) and the thermodynamics of irreversible process. The damage in rubber is described by an istropic law, whereas elasto-plastic continuum model has been proposed for cord–rubber interphase layer. The numerical framework is implemented into commercial finite element code Abaqus/Standard via user subroutine (UMAT).

One of the most important findings obtained from reviewing various techniques is that meso-level fatigue damage modeling based on developed framework can simulate competitive damage scenarios, e.g. debonding, delamination or matrix failure.

A systematic framework for predicting failure in cord-reinforced rubber composite is formulated within the context of CDMs that can also be applied for industrial components, such as tires and airsprings.