Mechanics of Solids最新文献

Multisource scattering problems in simulating seismic wave inputs to structures, such as large-span bridges, remain a longstanding challenge. To address this issue, a viscoelastic weighted artificial boundary is proposed based on the assumption of an infinite linear-elastic medium; in addition, its spring and damping coefficients were derived using the apparent velocity and wave-field separation theory. A few examples of single- and multi-source models were used to analyse the accuracy of the proposed boundary, considering the influence of the scattering source location and source count. The numerical results demonstrated that the accuracy of the proposed boundary was higher than that of comparable approaches for the same problems. In multisource examples, the accuracy could be improved by approximately 20% in most cases, whereas in cases with a large source distance and uneven spatial distribution, the accuracy could be further improved by approximately 40%. These results confirm that the proposed solution can effectively simulate earthquake ground motion inputs for multipoint sources with large source distances and uneven spatial distributions.

This article conducts an analysis and research on the issue of crater growth when an eroding rod penetrates a plastic target. By explaining the movement speed of the projectile deformation interface, the evolutionary mechanism of the projectile’s mushroom head under different impact velocities is elucidated. Additionally, an analytical expression for the stress values in the high-pressure region of the projectile head is provided. Based on the dynamic theory of spherical/cylindrical cavity expansion and the power-law strain hardening material constitutive considering strain rate effects, an crater growth model is established. The results indicate a better alignment between the cylindrical crater growth model and numerical simulations. When determining the model’s boundary conditions, the separation boundary conditions of the actual contact surface between the eroding rod and the impacted target are summarized under ideal conditions.

The vibration characteristics of an isotropic and homogeneous elastic hollow cylinder with porosity, emphasizing the influence of the magnetic field in the context of poroelasticity, are investigated. The investigative method encompasses the resolution of motion equations, formulated as partial differential equations, through the application of Lame’s potential theory. This analytical process is augmented by the implementation of fitting boundary conditions, culminating in the derivation of a comprehensive expression for the complex dispersion equation, predicated on the premise that the wavenumber embodies a complex entity. The precision of the model is corroborated through a comparative analysis with established literature, underpinned by an exploration of diverse scenarios. The research employed MATLAB for both numerical and graphical assessments, focusing on the dispersion and displacement attributes. Dispersion relations within the poroelastic medium were computed, considering varied magnitudes of magnetic field intensity and angular velocities. The outcomes are articulated through complex-valued dispersion relations, transcendental formulations, and numerical resolutions employing MATLAB’s bisection technique. These insights hold substantial significance for the theoretical advancement in orthopedic research, particularly concerning cylindrical poroelastic media. This study deduces that the radial vibrational patterns and the corresponding frequency equation within a poroelastic medium are profoundly modified by the magnetic field’s interference.

A novel transversely isotropic functionally graded magneto-electro-elastic third-order shear deformation microbeam model is constructed by utilizing a variational formulation based on Hamilton’s principle. This work takes the microstructure effect into account by using an extended modified couple stress theory. Three types of temperature distributions are considered. Using the framework and approaches shown above, the equations of motion along with the complete boundary conditions can be obtained in a reasonable process. For illustration purposes, a numerical example is presented to examine the influences of temperature distributions, beam thickness and functionally graded power-law index on thermal buckling. In order to solve the governing equations, a specific set of Fourier series which satisfy the boundary conditions are introduced. Furthermore, it is indicated that the shear deformation effect should be considered in predicting the buckling response, especially for a smaller slenderness ratio. Additionally, two types of simplified versions of this innovative microbeam model were also created for more straightforward applications. The shape correction factor is involved in establishing the corresponding first-order shear deformation model (Timoshenko microbeam model) for the sake of approximating the overall effect of nonhomogeneous shear stress. This article can offer guidelines for the safe design of micro- and nano-electromechanical systems devices.

This study uses a theoretical mathematical and physical model to investigate the interaction between electrons and holes in a semiconductor material. Our focus is on studying the elasto-thermodiffusion (ETD) theory, particularly in the context of photothermal transport processes that incorporate the influence of microtemperature. The examination of the governing equations considers the impact of the magnetic field. We study the one-dimensional deformation resulting from the interplay of electronic and thermoelastic phenomena, including hole mechanisms. For the primary physical parameters, we obtain dimensionless field values theoretically. To solve the system of equations, we use mathematical methods such as Laplace transforms and account for specific initial conditions. The initial conditions are defined at the boundary for the primary physical fields, which experience ramp heating in the Laplace domain. We then use Laplace inverse transforms and approximations to obtain closed-form solutions in the time domain for the main fields. Graphical comparisons are made to analyze the propagation of these fields under various parameters when the stability cases are studied. The study aims to determine whether or not one-dimensional stabilities predominate at a specific magnetic field, which is relevant for industrial or environmental applications. The paper goes into great detail about these findings.

In the context of the three-phase hysteresis model (3PHL), a system of equations is established for a generalized thermoelastic medium under the influence of a magnetic field and an internal heat source. The problem is discussed using Eringen’s nonlocal elastic model. The exact expression of the physical quantity is obtained by normal mode analysis and illustrated graphically by comparison and discussion. All calculation results obtained are graphically presented and explained. This paper investigates a specific type of material called a generalized magneto-thermoelastic medium. This material is subjected to the presence of a non-locality parameter and an internal heat source using the three-phase-lag model.

The excavation load is jointly borne by the surrounding rock and tightly-fitted lining, with different contact modes affecting the bearing effect. Therefore, this paper proposes a novel mechanical model of lining support to investigate the interaction between the lining and surrounding rock, particularly considering voids caused by tunnel excavation. By employing complex variable function method and optimization technique, it becomes possible to identify complete contact zones as well as void zones between the lining and surrounding rock, while also solving stress components at any point within them. Compared to other contact modes such as full contact, the proposed contact mode better reflects reality by avoiding occurrence of contact tensile stress during actual conditions. Subsequently, an analysis is conducted on how Young’s modulus of the lining, lateral pressure coefficient, and displacement release coefficient influence on voids. These research findings unveil the actual working mechanism behind lining support and provide a reliable theoretical foundation for preliminary design and void detection in lining support engineering.

An analytical solution has been derived for seismic ground motion in a saturated frozen soil free field under plane S-wave incidence. This solution was achieved by establishing a model based on the theory of elastic wave propagation in single-phase elastic media and frozen saturated porous media. Numerical calculations were conducted to analyze the seismic ground motion and assess the influence of various physical and mechanical parameters, including incident angle, incident frequency, porosity, medium temperature, cementation parameters, and contact parameters. The analysis revealed a positive correlation between horizontal ground surface displacement and increases in incident frequency, medium temperature, Poisson’s ratio, and contact parameter. Conversely, there was a slight decrease with increased porosity. Particularly significant were the effects of incident frequency and medium temperature on horizontal ground surface displacement. Vertical displacement decreased with increases in porosity, medium temperature, Poisson’s ratio, and contact parameter. The impact of incident frequency on vertical displacement was insignificant, but noticeable variations occurred when the angle of incidence approached the critical angle.

Vertical displacement decreased with increases in porosity, medium temperature, Poisson’s ratio, and contact parameter.

In order to understand the influence of non-local effects of rural road subsoil soil skeleton on the vibration attenuation of rural roads randomly induced by engineering construction vehicles. This study aims to establish a coupled 1/4 vehicle-rural road vibration response model considering non-local effects of soil skeleton and non-local effects of fluid in rural road subgrade, and to form a coupled vehicle-rural road interaction system considering non-local effects of soil skeleton and non-local effects of fluid in rural road subgrade. It reveals the influence of the non-local effect of soil skeleton and non-local effect of fluid on the coupled vibration response characteristics of rural roads under the random excitation of engineering construction vehicles. The results show that at low frequencies, the geometric factor of soil skeleton is the main factor affecting the amplitude and pore pressure of the rural road in semi-infinite space under the random excitation of engineering construction vehicles, and the non-local superposition effect of fluid in the soil has little effect on the amplitude and pore pressure. Road surface condition is the key factor affecting the vibration level of rural roads in infinite space under random excitation of engineering construction vehicles. Vehicle speed is the decisive factor affecting the vibration degree of rural roads on infinite space under random excitation of engineering construction vehicles. Thus, the effects of non-local effects of soil skeleton, non-local effects of fluid in soil, road surface unevenness and vehicle speed on the vibration degree of rural roads are clarified. The coupled engineering vehicle-rural road vibration theory system is improved.

The present investigation is focussed on waves propagation in an isotropic homogeneous, porous elastic plate subjected to conditions in context of stress free. The symmetric and skew-symmetric secular equations for wave mode propagation are deduced. The results of thin plate are also obtained. The determinant of secular equation of Rayleigh–Lamb, velocity of Rayleigh–Lamb phase, and attenuation coefficient are shown graphically for different various values of frequency, porosity parameter, compressibility constituents and thickness of the plate with wave number. A particular case is also deduced. Attenuation coefficient and phase velocity for Rayleigh–Lamb wave by computational simulations are calculated. In order to have a deeper understanding of Rayleigh–Lamb wave propagation, this inquiry looks beyond simple calculations and analyses particle motion. Additionally, research studies the effects of frequency factors and porosity on these wave phenomena. The findings of this work shed light on a number of unusual situations that greatly advance our knowledge of Rayleigh–Lamb wave propagation in this complex material system, especially when porosity is included. This study has been formulating a novel basic equations for an isotropic homogeneous porous elastic plate, highlighting the Rayleigh–Lamb waves significance and investigating the several parameters impact on the phenomenon.