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Galliot C.,Empa - Swiss Federal Laboratories for Materials Science and Technology | Rousseau J.,University of Burgundy | Verchery G.,Institut Superieur des Materiaux et Mecaniques Avances du Mans
International Journal of Adhesion and Adhesives

Crashworthiness of composite structures is a key issue for the design of lightweight vehicles. In particular the joined parts of the structures must be able to absorb a high amount of energy in order to protect the passengers. In this paper the dynamic behavior of adhesively bonded carbon/epoxy laminate joints is investigated. The adherends are made of unidirectional plies, whose orientations are carefully chosen in order to assess the influence of the adherend mechanical properties on the joint behavior. A drop weight machine has been modified in order to impact specimens under tension. Single lap joints are tested under impact tension at velocities from 1 to 4 m/s. Results of the impact tests that are compared to reference quasi-static test results emphasize the rate-sensitivity of the joints. The stiffness, the failure load and the absorbed energy all increase with increasing loading rate. One major result is that the joint behavior is qualitatively the same under quasi-static and impact loading: the failure mode and the joint ranking (based on their strength) remain identical. Therefore the impact design of the adhesive joints could be based on a static design at moderate loading rates. © 2012 Elsevier Ltd. All rights reserved. Source

Abe S.,Mie University | Abe S.,Institut Superieur des Materiaux et Mecaniques Avances du Mans
Journal of Statistical Mechanics: Theory and Experiment

The problem of extracting the work from a quantum-thermodynamic system driven by slowly varying external parameters is discussed. It is shown that there naturally emerges a gauge-theoretic structure. The field strength identically vanishes if the system is in an equilibrium state, i.e., the nonvanishing field strength implies that the system is in a nonequilibrium quasi-stationary state. The work done through a cyclic process in the parameter space is given in terms of the flux of the field. This general formalism is applied to an example of a single spin in a varying magnetic field, and the maximum power output is discussed in a given finite-time cyclic process. © IOP Publishing Ltd. Source

Kazemi M.,Islamic Azad University at Eslamshahr | Verchery G.,Institut Superieur des Materiaux et Mecaniques Avances du Mans
Composite Structures

Buckling strength is the most important design criterion for laminated composite structures subjected to compressive loading. The aim of the present work is to introduce an explicit procedure in designing laminated composite plates for maximum buckling load subjected to strength and stiffness constraints using the polar formalism, which relates stiffness to the critical buckling load in order to simplify the calculation and optimization of the buckling load. The polar representation of plane elasticity is effectively used in this work in order to introduce a unified optimization method. Design for maximum flexural stiffness as well as laminate effective elastic modulus was developed in order to achieve the optimal orientation of the layers giving the maximum buckling strength. Three optimization procedures were proposed. The first one is unconstrained optimization and the two other cases are constrained optimization subjected to the flexural stiffness and the elastic modulus constraints. The quasi-homogeneous laminates, which have been used as a special class of laminate stacks, were proposed as the general solution for the optimal stacking sequence of the layers. © 2016 Elsevier Ltd. Source

Piyanzina I.,Kazan Federal University | Minisini B.,Institut Superieur des Materiaux et Mecaniques Avances du Mans | Tayurskii D.,Kazan Federal University | Bardeau J.-F.,University of Maine, France
Journal of Molecular Modeling

Density functional theory (DFT) calculations have been used to investigate the structural properties, dipole moments, polarizabilities, Gibbs energies, hardness, electronegativity, HOMO/LUMO energies, and chemical potentials of trans and cis configurations of eight para-substituted azobenzene derivatives. All properties have been obtained using the B3LYP functional and 6-31++G(d,p) basis set. The planar structures have been obtained for all optimized trans configurations. The energy difference between trans and cis configurations for considered derivatives was found to be between 64.2–73.1 kJ/mole. It has been obtained that the p-aminodiazo-benzene (ADAB) has the difference in the dipole moments between trans and cis forms higher than for trans and cis azobenzene. © 2014, Springer-Verlag Berlin Heidelberg. Source

Abe S.,Mie University | Abe S.,Institut Superieur des Materiaux et Mecaniques Avances du Mans | Abe S.,Inspire Inc.
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics

In their work, Bender, Brody, and Meister have shown by employing a two-state model of a particle confined in the one-dimensional infinite potential well that it is possible to construct a quantum-mechanical analog of the Carnot engine through changes of both the width of the well and the quantum state in a specific manner. Here, a discussion is developed about realizing the maximum power of such an engine, where the width of the well moves at low but finite speed. The efficiency of the engine at the maximum power output is found to be universal independently of any of the parameters contained in the model. © 2011 American Physical Society. Source

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