Mechanics of Time-Dependent Materials最新文献

This study investigates the thermo-mechanical behavior of generalized thermoelastic mediums under the influence of gravitational fields, incorporating two-temperature effects through the Lord–Shulman and dual-phase-lag models. Focusing on a plane surface subjected to an arbitrary normal force and maintained at isothermal conditions, analytical expressions for conductive temperature, thermodynamic temperature, displacement components, and force stresses are derived using normal mode analysis. Numerical results, presented graphically, consider the application of thermal force. Comparative analyses between the dual-phase-lag and Lord-Shulman models are conducted, examining the impact of gravity and the two-temperature effect. Engineering applications of these findings can enhance the understanding of thermal management in materials subjected to varying gravitational environments, such as aerospace structures and thermal barrier coatings.

The role of stress-induced diffusion (SID) in influencing the mechanical response and diffusion of Li in viscoelastic electrode particles of Lithium-ion batteries is studied. A two-way coupled chemo-viscoelastic model is developed for this purpose, and the governing equations are solved via the finite element method using deal. ii, an open source C++ library. Comparative studies between one-way and two-way coupled chemo-viscoelastic models reveal that concentration and stress are initially larger for the two-way coupled model, but later they reduce in magnitude compared to the one-way coupled model. The level of filling at which the switch is observed decreases with increase in particle size. The switch occurs due to change in the sign of gradient of hydrostatic stress for a viscoelastic material from negative to positive and its concurrent effect on diffusive flux as a result of two-way coupling between stress and diffusion. Further, from comparative studies between two-way coupled elastic and viscoelastic models, it is observed that speed of filling is greater for an elastic particle in comparison to a viscoelastic particle, and the gap increases when the particle size is smaller. In addition, lower values of stresses are observed for viscoelastic electrode particles, and the difference between maximum stress generated increases with increase in particle size. Thus, the time scales associated with viscoelastic constitutive response and diffusion process alters the SID effects and could be tuned while designing electrodes to mitigate slowing down of diffusion and fracture.

This paper introduces a fractional-order model integrated with a damage variable to effectively characterize the stress or strain responses under strain- or stress-controlled cyclic loading. We derive a relationship among mean stress, ratcheting strain, and cyclic number from the established fractional constitutive relationship. Experimental validation with polymeric data demonstrates the validity of our model, indicating how fractional order captures the effects of various loading conditions—including mean stress, temperature, and loading rate—on ratcheting strain responses. Additionally, our model offers a simpler mathematical framework than the existing models, without compromising accuracy.

This research investigates the impact of thermoelastic coupling on thermally conducting, homogeneous, and isotropic Kelvin–Voigt-type circular microplate resonators. The study utilizes the Moore–Gibson–Thompson technique, which incorporates viscous effects. We examine the use of clamped boundary conditions and obtain analytical solutions in the Laplace-transform domain. In order to clarify the thermomechanical effects on the vibrations of a ceramic Si₃N₄ plate resonator, we calculate numerical outcomes in the time domain by employing the inverse Laplace transform. We examine the impact of viscosity on many physical phenomena, including deflection, temperature, displacement, thermal moment in the radial direction, and radial stress. We give graphical findings that compare the results with and without the presence of viscosity. The study evaluates the precision and feasibility of the MGTE thermal-conductivity theory by comparing its numerical outcomes with well-established thermoelastic models, such as the classical theory, Lord–Shulman theory, and Green–Naghdi II and III theories. The MGTE theory showcases improved accuracy, facilitating the production of circular micro/nanoplate resonators with exceptional quality and decreased energy dissipation.

This article addresses the thermomechanical thermal buckling and free vibration response of a novel smart sandwich nanoplate based on a sinusoidal higher-order shear deformation theory (SHSDT) with a stretching effect. In the proposed sandwich nanoplate, an auxetic core layer with a negative Poisson’s ratio made of Ti-6Al-4V is sandwiched between Ti-6Al-4V rim layers and magneto-electro-elastic (MEE) face layers. The MEE face layers are homogenous volumetric mixtures of cobalt ferrite (CoFe₂O₄) and barium titanate (BaTiO₃). The mechanical and thermal material properties of the auxetic core and MEE face layers are temperature-dependent. Using Hamilton’s principle, governing equations are constructed. To characterize the size-dependent behavior of the nanoplate, governing equations are adapted with the nonlocal strain gradient theory (NSGT). By applying the principles of Navier’s technique, closed-form solutions are obtained. Parametric simulations are carried out to examine the effects of auxetic core parameters, temperature-dependent material properties, nonlocal parameters, electric, magnetic, and thermal loads on the free vibration and thermal buckling behavior of the nanoplate. According to the simulation results, it is determined that the auxetic core parameters, temperature-dependent material properties, and nonlocal factors significantly affect the thermomechanical behavior of the nanoplate. The outcomes of this investigation are expected to contribute to the advancement of smart nano-electromechanical systems, transducers, and nanosensors characterized by lightweight, exceptional structural integrity and temperature sensitivity. Also, the auxetic core with a negative Poisson’s ratio provides a metamaterial feature, and thanks to this feature, the proposed model has the potential to be used as an invisibility technology in sonar and radar-hiding applications.