Mechanics of Time-Dependent Materials最新文献

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 effects of multi-slip conditions and entropy production on the flow of viscoelastic (Jeffrey) nanofluids in asymmetric channels, to determine the implications for healthcare applications such as cryopreservation and therapeutic thermal devices. By employing numerical simulations via the Shooting method and NDSolve tool, we examine the influence of motile microorganisms on the fluid’s thermal and entropic characteristics. Our findings, illustrated through graphical analysis, demonstrate that optimizing thermal slip and minimizing viscous slip can significantly reduce entropy generation. Additionally, we observe that the thermal profiles are affected by the Brinkman number-diminishing in size, yet expanding due to the Jeffrey fluid’s properties. This investigation not only advances our understanding of microbe motion in physiological fluids but also opens directions for developing precise therapeutic and diagnostic tools for microbial infections and related disorders.

Pressure tubes (PTs) play an important role in the safe and efficient operation of Nuclear Power Plants (NPPs) as they contain the fuel bundles and provide structural integrity. Creep has been identified as one of the main degradation mechanisms of PTs, which are made widely of Zr-Nb alloys. The creep curve of a material gives an insight into the nature of its creep behavior. In the present investigation, accelerated creep experiments were conducted on Zr-2.5Nb PT alloy in the stress and temperature range of 22–58 MPa and 600–850 °C, respectively. Two data-driven models, namely Radial Basis Function Neural Network (RBFNN) and Least Square Fit (LSF) were developed to simulate the non-linearity of the creep curves. Applied stress, test temperature, and time to failure were taken as the input parameters for the models. It was observed that although the LSF could predict the primary creep zone, it failed to predict the transition between the secondary and tertiary creep region. However, the creep curves predicted by the RBFNN model were in close agreement with the experimental results, having a confidence level of ≈ 0.99. Two separate sets of creep experiments were also done later to verify the accuracy of the proposed models. The results from the study established the ability of the RBFNN technique to simulate the complex behavior of the creep curves.

The present article addresses a novel mathematical model involving the Atangana-Baleanu (A-B) definition of fractional derivatives in time that offers a new interpretation of the thermo-mechanical effects inside skin tissue during thermal therapy. A Laplace transform mechanism is proposed to achieve closed-form solutions for prominent physical quantities, such as temperature, displacement, strain, and thermal stress. Computational results are obtained in time domains using an efficient numerical inversion algorithm of Laplace transform. The impact of the fractional parameter is investigated on the variations of the field quantities through the graphical results. The behavior of each physical field is speculated against the time parameter. The domain of influence of each field quantity is suppressed when the definition of the Atangana Baleanu fractional model is adopted, replicating that the waves under the A-B fractional model predict the finite nature of propagation compared to the conventional heat transport model. Further, we observe that the nature of the thermo-mechanical waves becomes stable earlier inside the tissue.

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.

We investigate the aging behavior of High-Density Polyethylene (HDPE) pipelines, specifically comparing the Pipe Body (PB) and Butt-Fusion Welded Joint (BFWJ) under thermal oxidative and hydrothermal accelerated aging conditions. Our results indicate that the performance disparity between PB and BFWJ diminishes as aging time increases. We also find that the specimen type affects the quantity of polyethylene fibers, with hydrothermal aging significantly affecting the cohesive force among these fibers in both PB and BFWJ. These findings on differential aging processes of PB and BFWJ contribute to a deeper understanding of HDPE pipeline durability and offer practical recommendations for mitigating degradation risks associated with these disparities. This research underscores the importance of considering specific aging behaviors in the maintenance and reliability assessment of HDPE pipeline systems used in energy transport, industrial, and agricultural applications.

This paper investigates the thermoelastic behavior of porous materials under magnetic fields using a dual-phase lag (DPL) model, with a specific focus on an unbounded porous body containing a cylindrical cavity. By applying the Laplace transform to address the time-dependent aspects of the governing equations, we investigate the effects of harmonically varying heat loads on the material’s porous–thermoelastic response. Numerical simulations provide insights into the distribution of excess pore water pressure, temperature, displacement, thermal stresses, and the magnetic field within the material. Results are presented through graphical analyses, facilitating a detailed comparison of porous–thermoelastic behaviors under different conditions. This approach not only validates the model’s accuracy but also enhances our understanding of porous materials’ responses to thermal and magnetic stimuli, offering valuable implications for their design and safety in engineering applications.