1,720,972 research outputs found
Thermomechanics of damageable materials under diffusion:modeling and analysis
Full text linkWe propose a thermodynamically consistent general-purpose
model describing diffusion of a solute or a fluid in a solid undergoing possible phase transformations and damage, beside possible visco-inelastic processes. Also heat generation/consumption/transfer is considered. Damage is modelled as rate-independent. The applications include metal-hydrogen systems with metal/hydride phase transformation, poroelastic rocks, structural and ferro/para-magnetic phase transformation, water and heat transport in concrete, and, if diffusion is neglected, plasticity with damage and viscoelasticity, etc. For the ensuing system of partial differential equations and inclusions, we prove existence of solutions by a carefully devised semi-implicit approximation scheme of the fractional-step type
Thermomechanics of hydrogen storage in metallic hydrides: modeling and analysis
Full text linkAbstract. A thermodynamically consistent mathematical model for hydrogen adsorption in metal hydrides is proposed. Beside hydrogen diffusion, the model accounts for phase transformation accompanied by hysteresis, swelling, temperature and heat transfer, strain, and stress. We prove existence of solutions of the ensuing system of partial differential equations by a carefully-designed,semi-implicit approximation scheme. A generalization for a drift-diffusion of multi-component ionized “gas” is outlined, too
Quasistatic delamination problem
Full text linkWe study delamination of two elastic bodies glued together by an adhesive that can undergo a unidirectional inelastic rate-independent process. The quasistatic delamination process is thus activated by time-dependent external loadings, realized through body forces and displacements prescribed on parts of the boundary. The novelty of this work consists of considering the glue as infinitesimally thin and ideally rigid in the sense that a crack in the glue cannot be seen before, speaking ``microscopically'', all macromolecular links of the adhesive are fully debonded. The concept of energetic solution is applied and existence of such solutions is proved by showing Gamma-convergence of a suitable approximation that, in addition, allows for a direct computer implementation, unlike the original problem
Ferromagnets with eddy current and pinning effects: their thermodynamics and analysis
Full text linkExistence of weak solutions is proved for a system of nonlinear parabolic equations/inequalities describing evolution of magnetization, temperature, magnetic field, and electric field in electrically-conductive unsaturated ferromagnets. The system is derived from a recently-proposed thermodynamically-consistent continuum theory for the ferro/paramagnetic transition. Besides the standard viscous-like damping, dissipation due to eddy currents and domain-wall pinning is considered
The Gilbert equation with dry-friction-type damping
Full text linkA modified Gilbert equation for micromagnetics is considered, obtained by augment- ing the standard viscous-like dissipation with a rate-independent term. We prove existence of a weak solution both with and without viscous dissipation. By scaling time we show that, if the applied field varies very slowly, then gyromagnetic effects and viscous dissipation become negligible. In the infinitesimally-slow-loading limit, the system thus becomes fully rate-independen
Quasistatic delamination of sandwich-like Kirchhoff-Love plates
Full text linkA quasistatic rate-independent adhesive delamination problem of laminated plates with a finite thickness is considered. By letting the thickness of the plates go to zero, a rate-independent delamination model for a laminated Kirchhoff-Love plate is obtained as limit of these quasistatic processes. The same dimension reduction procedure is eventually applied to processes which are sensitive to delamination modes, namely opening vs. shearing is distinguishe
A thermodynamically consistent theory of the ferro/paramagnetic transition
No full textWe propose a continuum theory describing the evolution of magnetization and temperature in a rigid magnetic body. The theory is based on a microforce balance, an energy balance, and an entropy imbalance. We advance the choice of a class of constitutive equations, consistent with the entropy imbalance, that appear appropriate to describe the phase transition taking place in a ferromagnet at the Curie point. By combining these constitutive equations with the balance laws, we formulate an initial-boundary value problem for the magnetization and temperature fields, and we prove existence of weak solutions
Quasistatic delamination models for Kirchhoff-Love plates
No full textA quasistatic rate-independent brittle delamination problem and also an adhesive unilateral contact problem is considered
on a prescribed normally-positioned surface in a plate with a finite thickness. By letting the thickness of the plate go to
zero, two quasistatic rate-independent crack models with prescribed path for Kirchhoff-Love plates are obtained as limit
of these quasistatic processes
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