Journal of Applied and Computational Mechanics
Volume:10 Issue: 2, Spring 2024

In this paper, the influence of the Coefficient of Thermal Expansion (CTE) on the thermal stress analysis of laminated composite plates is explored. By introducing the undetermined integral terms in the displacement field, a new simple and efficient higher-order shear deformation theory is formulated for the thermo-mechanical behavior of thick laminated composite plates. This formulation aims to reduce the number of generated unknowns. Typically, a reduced order of the governing partial differential equations is expressed using the principle of virtual displacements. By using Navier’s technique, closed-form solutions are derived for laminated composite plates under thermal and/or mechanical loading. Unfortunately, several traditional research investigations significantly depend on the rule of the mixture to determine reliable CTE for composites. This paper offers and examines a variety of analytical micromechanics-based models for estimating CTE in laminated composite materials, incorporating into consideration different considerations. The obtained results are compared to those given by other alternative plate theories, and the efficiency and accuracy of the present theory are demonstrated for the thermomechanical behavior of laminated composite plates. This study reviews and applies several micromechanics-based models, contrary to previous investigations. Laminated composite plates could delaminate or crack due to the matrix material's longitudinal CTE, affecting fiber volume fraction and stacking sequence. Micromechanics-based approaches are important when arbitrary thermo-mechanical characteristics can generate inaccuracies. Interestingly, micromechanics-based models can estimate effective CTE. Schapery, Chamberlain, and Chamis provide models with identical longitudinal CTE. For increasing fiber volume fractions, Chamberlain's model is more sensitive to increasing fiber volume fractions. Mechanical stress changes laminated plate behavior more than thermal loading. Although all presented micromechanical-based models have simplified representations, this research attempts to provide a standard for future investigations. The use of detailed micromechanical-based models stimulates further progress in understanding and utilizing complex composite plates.

Simulations that calculate the breakage of a given material allow for estimating the particle size produced by comminution equipment. However, conducting these simulations requires a significant amount of time and incurs high computational costs due to the progressive increase in the number of particles during the breakage events. This challenge has prompted the exploration of alternatives, such as employing impact energies present in simulations with solid particles. This study examines the application of two breakage models to particle speeds, analyzing the correlation between the t10 value obtained from simulations using solid particles and the value obtained when simulations include breakage. The findings reveal a linear relationship between the results obtained from simulations with breakage and those with solid particles for a rotor that primarily impacts particles during their initial collisions. This relationship holds true for variations in rotor RPM as well as fluctuations in feed flow.

This research aims to examine the tensile strength of a hybrid composite laminate reinforced by thin-plies when used as an adherend in bonded single lap joints subjected to high-rate and impact loading. Two different composites, namely Texipreg HS 160 T700 and NTPT-TP415, are employed as the conventional and thin-ply composites, respectively. The study considers three configurations: a conventional composite, a thin-ply, and a hybrid single lap joint. Numerical models of the configurations are developed to provide insight into failure mechanisms and the initiation of damage. The results indicate a significant increase in tensile strength for the hybrid joints over the conventional and thin-ply joints, due to the mitigation of stress concentrations. Overall, this study demonstrates the potential of hybrid laminates for improving the performance of composite joints under high-rate loading and impact conditions.

In this study, a meshfree framework based on the reproducing kernel collocation method is proposed for incremental-iterative analysis of double-diffusive natural convection in a porous enclosure, in which the forward difference method is adopted for temporal discretization, and the two-step version of Newton-Raphson method is used for iteration. As the double-diffusive convection problem is composed of multi phases and is influenced by both material and geometric parameters, the resulting system is highly nonlinear and complicated. From the numerical investigation, the partially heated boundary with different buoyancy ratios can yield monocellular flow problems with opposite phenomena depending on the contribution of thermal/solute buoyancy force. For the domains with burrowing inside, the key feature is the contour of stream function, which is separated into two vortexes by the hole in the simply connected domain while the two vortexes are not separated completely in the multiply connected domain due to the geometric compression of two holes. It is further shown that the framework is capable of solving various double-diffusive convection problems with satisfactory accuracy and efficiency by uniform discretization as well as few source points in the approximation.

Darcy-Forchheimer model has been used to consider the mathematical and statistical aspects of Prandtl nanofluid flow on a stretched curvy geometry, with homogenic-heterogenic reactions, nonlinear radiation, exponential heat, Joule heating, velocity slip, and convective heat conditions. An account of entropy significance has been given to boost the applicability of the study. The 4-5th ordered numerical tool, Runge-Kutta-Fehlberg, has been employed to establish the plots for the considered flow. ANOVA and Taguchi optimisation technique is used to obtain the optimal condition in enhancing the heat transfer rate for modelled mathematical problem. Here, the study reveals that the increasing homo-heterogenic strength parameters foster the concentration profile. The study also found that the thermal curves are positively affected by the radiation parameter and the temperature differential parameter. In addition to this, graphical portraits of isotherms and streamlines have been given to characterise the flow and heat pattern. Taguchi method reveal that first level of Prandtl number, magnetic parameter, Weissenberg number, heat source parameter and third level of curvature parameter, produce maximum Nusselt number. Heat source parameter has large contribution of about 49.45% among the other parameters and Prandtl number has the least contribution of about 1.4% for optimisation.

This study focuses on improving the thermal characteristics of a plate-finned heat sink (PFHS) by incorporating a vapor chamber (VC) through experimental investigation. The research examines the influence of various parameters, including Reynolds number (Re), heat input, filling ratio (FR), and operating vacuum pressure, on the thermal performance of the VC. The results demonstrate that the utilization of a VC leads to a significantly more uniform temperature distribution along the base of the PFHS and low overall temperatures. Conversely, in the absence of a VC, the PFHS exhibits a non-uniform temperature distribution, with a bell-shaped profile and concentrated high temperatures at the center at the same operating conditions. The results indicate that an operating vacuum pressure of 1kPa produces the most favorable performance. Additionally, a filling ratio of 50% proves to be optimal across the range of heat inputs from 10 to 90 W.

This research considers the Kraenkel-Manna-Merle system with an M-truncated derivative (K-M-M-S-M-T-D) that defines the magnetic field propagation (M-F-P) in ferromagnetic materials with zero conductivity (F-M-Z-C) and uses the Sardar sub-equation method (S-S-E-M). Our goal is to acquire soliton solutions (SSs) of K-M-M-S-M-T-D via the S-S-E-M. To our knowledge, no one has considered the SSs to the K-M-M-S-MTD with or without a damping effect (DE) via the S-S-E-M. The SSs are achieved as the M-shape, periodic wave shape, W-shape, kink, anti-parabolic, and singular kink solitons in terms of free parameters. We utilize Maple to expose pictures in three-dimensional (3-D), contour and two-dimensional (2-D) for different values of fractional order (FO) of the got SSs, and we discuss the effect of the FO of the K-M-M-S-MTD via the S-S-E-M, which has not been discussed in the previous literature. All wave phenomena are applied to optical fiber communication, signal transmission, porous mediums, magneto-acoustic waves in plasma, electromagnetism, fluid dynamics, chaotic systems, coastal engineering, and so on. The achieved SSs prove that the S-S-E-M is very simple and effective for nonlinear science and engineering for examining nonlinear fractional differential equations (N-L-F-D-Es).

Various industrial sectors require highly specialized and efficient materials for applications in fields such as the military, aeronautics, aerospace, and mechanical and civil engineering. Composite materials that meet the stringent requirements across these domains have become prominent, often serving as structural components and requiring precise mathematical modeling. Zigzag (ZZ) and Layerwise (LW) theories are commonly used for laminated-beam structural analysis. Although the LW theory provides superior accuracy, it suffers from an increase in unknowns as the number of layers grows. Conversely, the ZZ theory is less computationally intensive and less accurate. This study proposes an exponential high-order zigzag function with a unified kinematic formulation to enhance the accuracy of the ZZ theory. The results were compared with those of existing models and demonstrated excellent agreement with the reference solutions, irrespective of the layer count or slenderness index, making it a more efficient choice for laminated-beam analysis.

The purpose of this study is to look at how gold nanoparticles affect the circulation near wavy biological cell walls. Non-linear thermal radiation was found to enhance the heat transfer rates of nanofluid flow by numerical calculations. The mathematical model was a temporally magnetized non-Newtonian Casson micropolar nanofluid flow through a heated vertical wavy surface. The importance of predicting heat and mass transfer for irregular surfaces cannot be overstated, as irregular surfaces are common in many applications, including refrigerator condensers and flat-plate solar collectors. For this reason, it is imperative to study heat and mass transfer in complex geometries. Furthermore, the fluid temperature factors like nanofluid viscosity and microrotation viscosity were taken into account. A graph comparing the published data and the present numerical computation revealed an exact match. A physical interpretation of images was provided to describe the phenomenon of blood flow by heat transfer according to various circumstances. In medical treatment, especially cancer therapy, these results are crucial. Gold nanoparticles are among the best particles because they are stable metallic nanoparticles with excellent catalytic, magnetic, and optical properties. The investigation's findings showed that as time-steps grow, each profile's effectiveness tends to decrease, moving the unstable condition closer to the steady state. Whereas, the sphere-shaped nanoparticles have a significant effect on temperature profile change, column-shaped nanoparticles have less effect. Local skin friction rises and the local Nusselt number falls when the values of the two surface amplitude parameters rise.

The paper deals with the combined effect of non-Newtonian saturating fluid and horizontal flow rate on the thermal convection in a highly permeable, porous plane layer saturated with a power-law model. Asymmetric boundary conditions are assumed, with a cooled free surface at the top and a heated, impermeable, rigid wall at the bottom. The generalised Forchheimer equation is employed to model the power-law fluid movement. Convection cells emerge in the power-law fluid because of vertical temperature gradient imposed by the thermal boundaries. The onset of this scenario can be studied using linear stability theory, which leads to an eigenvalue problem. The latter is solved either numerically, employing shooting schemes, or analytically, using one-order Galerkin approach. The present study is considered an extension of the classical Prats problem. When the Peclet number, which defines the flow rate, is negligible, the configuration switches to the special case of Darcy-Rayielgh instability. The results show that the form drag exhibits a stronger stabilizing influence in shear-thinning fluids compared to shear-thickening and Newtonian ones since the saturating fluid is described by the power-law model. This scenario appears in the specific range of the Peclet number. In general, this investigation can be used to understand the heat transfer process in subsurface hydrocarbon reservoirs where the fluid may exhibit non-Newtonian behaviour.

The researchers have reported numerous numerical and analytical efforts in recent years to understand technological and industrial processes. Microelectronics, heat exchangers, solar systems, energy generators are just a few numbers of recent applications of heat and mass transfer flow. Two dimensional steady incompressible MHD flow of micropolar fluid over an inclined permeable surface with natural convection is investigated in this research work, with the contribution of thermal radiation under thermophoretic effects as a heating source. As a result of this infestation, mathematical model of the problem equations based on energy, momentum, angular momentum, mass, and concentration are developed. To convert the current problem into dimensionless ordinary differential equations, non-dimensional variables have been assigned. The evolved mathematical model is numerically solved aside utilizing Shooting technique along with 4th order R-K method solver in MATHEMATICA. The outcomes are displayed and analyzed through figures and tables. Finally, skin friction, Nusselt and Sherwood numbers are tabulated for distinct parameter-factors. To validate the accuracy of numerical method used in this problem, we compare the numerical results with available findings, and it is evident that the outcomes of current work are in good agreement with those reported in the literature. Improving the values of thermophoresis, radiation factors, and Schmidt number, declines the velocity. Higher values of radiation parameter, thermophoresis parameter, the microrotation increase near plane-surface and gradually diminishes far away from plane-surface. Profiles of temperature enhances with increasing the viscous dissipation parameter. Profiles of the concentration decreases by increasing the thermophoresis parameter and Schmidt number. Profiles of Skin friction and mass transfer rate decreases for magnetic field, thermal radiation and Schmidt number values.

DNA, or deoxyribonucleic acid, is found in every single cell and is the cell's primary information storage medium. DNA stores all an organism's genetic information, including the instructions it needs to grow, divide, and live. DNA is made up of four different building blocks called nucleotide bases: adenine (A), thymine (T), cytosine (C), and guanine (G). The genome is sequenced in vitro utilizing encoding strategies such as labelling one bond pair as 0 and the other as 1 to store digital information. In this study, the fractional differential order of double-chain DNA dynamical system was investigated, considering Atangana’s conformable fractional derivative. The conformable sub-equation method was applied to the system.  The analysis resulted in some interesting new exact solutions of the model. One-soliton kink solution, multiple-soliton solutions, and periodic-wave solutions are the three broad categories that may be used to describe the results. In order to better understanding the solutions found, we have visually investigated a few of them. Both solitary and anti-solitary waves of the DNA strands are seen, attesting to the nonlinear dynamics of the system. The gathered data might be used to conduct application evaluations and draw further scientific findings.

In this work, considering a propulsion system of a planing boat, the effects of the air ducts with a square cross-section on the thrust, torque, performance, and ventilation of the surface piercing propeller (SPP) are investigated. The fluid flow is simulated using solving of the Reynolds-averaged Navier–Stokes equations (RANS) by the multi-physics computational fluid dynamics software STAR-CCM+. The simulations are validated by studying its grid independency and comparing the numerical results with the extracted results from the sea trial. Then, by considering the actual arrangement of the duct and SPP, the SPP is examined in the open water test in five cases for both condition of the lack and existence of the aeration. Also, the effects of aeration, the advance coefficient and the immersion ratio on the hydrodynamic characteristics of the SPP are studied. In a constant distance between the air duct and propeller, the results show that by increasing the hydraulic diameter of the air duct, the torque and thrust decrease, and the efficiency remains almost constant. Also, it is numerically demonstrated that the effects of the advance coefficient on the torque and thrust coefficients are different for the models with and without aeration.

Variational principles are very important for a lot of nonlinear problems to be analyzed theoretically or solved numerically. By the popular semi-inverse method and designing trial-Lagrange functionals skillfully, new variational principles are constructed successfully for the Kuramoto-Sivashinsky equation and the Coupled KdV equations, respectively, which can model a lot of nonlinear waves in shallow water. The established variational principles are also proved correct. The procedure reveals that the used technologies are very powerful and applicable, and can be extended to other nonlinear physical and mathematical models.

A detailed analysis, is presented in this paper, for the steady gyrostatic nanofluid flow past a permeable stretching/shrinking sheet with slip condition using the nanofluid model proposed by Buongiorno. The microorganisms are imposed into the nanofluid to stabilize the nanoparticles to suspend due to a phenomenon called bioconvection. Considering appropriate similarity transformations, the five partial differential equations of mass conservation, momentum, thermal energy and microorganisms are reduced to a set of four ordinary (similar) differential equations with coupled linear boundary conditions. These equations   were both analytical and numerical solved using Runge-Kutta-Fehlberg technique. The influences of important physical parameters, such as, Prandtl number Pr, the Schmidt number Sc, the bioconvection Péclet number Pe, the Brownian motion parameter Nb, the thermophoresis parameter Nt and the stretching/shrinking parameter λ on the skin friction coefficient Cf and the local Nusselt number Nux, as well as on the velocity, temperature and gyration profiles, are interpreted through graphs and tables. Further, multiple (dual, upper and lower branch solutions) are found for the governing similarity equations and the upper branch solution expanded with higher values of the suction parameter. It can be confirmed that the lower branch solution is unstable. It is found that the bioconvection parameters have strong influence towards the reduced skin friction coefficient, reduced heat transfer, velocity and density of motile microorganism’s transport rates.