Nanofluid flow over a slanted stretching cylinder has impactful applications in heat exchangers, fiber and polymer processing, solar collectors and biomedical devices, as the flow of heat and mass can be greatly improved by the inclined geometry. In light of the listed substantial applications, this research investigates the impacts of curvature, viscous heating, angle-inclination, chemical interactions and Soret and Dufour facets on the radiative thermal propagative MHD nanofluid migration in the prevalence of convective heat and mass transfer via the slanted cylindrical structure ingrained in porous medium. The two types of nanoparticles Ag and Al2O3 are mixed with base fluid water to synthesize two different nanofluids. With the aid of MATLAB software, finite element method (FEM) was engaged to simplify the final ODEs aiming to perform the model's objectives. The ultimate outcomes revealed that thermal and velocity fields of both fluids noticeably increased by the viscous heating, thermal Biot number and heat radiation. The curvature and thermos-diffusion impacts incited to amplify all three flow fields. The flow velocity of both fluids substantially depreciated with magnetic field and inclination angle. The greater thermal source and diffusion-thermo instigated to rise thermal fields The concentration field of both fluids condensed by the solute Biot number and chemical reactive parameters. The friction-factor decreased pointedly by the nanoparticle concentration, angle inclination, Hartman number, curvature and viscous dissipation. Increased magnetic field, curvature and angle inclination of the surface caused to rise the Nusselt number. The Sherwood number appreciably raised with the chemical reaction, curvature and solutal Biot number.
Over the past few years, compliant mechanisms made of flexible parts have presented attractive alternatives to standard mechanical tools that are made by assembling a number of rigid links. In spite of their obvious advantages in manufacturing and usage, little work has been done in employing these compliant mechanisms into designing machines that perform complex set of functions. In this paper, as a first step towards this effort, we design a compliant pneumatic linear motor that can be manufactured into a single part without any assembly using additive manufacturing processes. This linear motor handles multiple functions such as actuation, valve opening, and closing. The design aspects of this motor are discussed in detail, and the performance of the linear motor is analysed for various geometric dimensions using Finite Element Analysis.
The present study aims to examine the large-amplitude free vibration of functionally graded material (FGM) sandwich plates including the combined influences of porosity, geometric imperfection, elevated temperature, flexible constraints of edges, and elastic foundations. The properties of constituent materials are temperature-dependent and effective properties of porous FGM are evaluated taking up a modified version of linear rule of mixture. Two sandwich models constructed from FGM and homogeneous layers are considered, and pores are evenly distributed in materials. Motion and compatibility equations in terms of deflection and stress function are derived on the basis of first order shear deformation theory incorporating initial geometric imperfection and von K & aacute;rm & aacute;n nonlinearity. The derived equations are solved by using analytical solutions along with Galerkin procedure to obtain a time nonlinear ordinary differential equation. This differential equation is resolved by means of the fourth-order Runge-Kutta numerical integration to seek the frequencies of nonlinear free vibration of sandwich plates. A parametric study is executed to analyze different effects of porosity volume fraction, imperfection, tangential restraints of boundary edges, elastic foundations, and elevated temperature on the natural frequencies and frequency ratio-amplitude response. It is revealed that tangential edge constraints dramatically affect the linear and nonlinear frequencies, especially at high temperatures. Additionally, the support of elastic foundations increases the natural frequencies of the plates, but also weakens the frequency nonlinearity.
This study introduces a novel bio-inspired microstructure, the Reentrant Spidroin Element (RSE), inspired by the remarkable mechanical properties of spider silk. This work proposes a reentrant auxetic structure incorporating the RSE to investigate its mechanical behavior, specifically focusing on its Poisson's ratio and Young's modulus. The design leverages the unique auxetic property of a negative Poisson's ratio, which enables the material to contract perpendicularly to the direction of compression and expand perpendicularly to the direction of tension. This characteristic offers significant potential for applications in fields such as biomedical engineering, aerospace, and flexible electronics. The mechanical properties of the RSE are derived analytically using curved beam theory and Castigliano's theorem, providing a robust framework for modeling the unit-cell's deformation behavior based on its geometrical and material parameters. Key geometrical parameters-including the initial length and radius of the spidroin element, and a secondary length parameter-are systematically analyzed to understand their influence on the auxetic behavior and stiffness of the structure. The analytical model is validated through finite element analysis (FEA), which demonstrates excellent agreement between theoretical predictions and numerical simulations (with a maximum relative deviation below 0.5%), thereby confirming the reliability and accuracy of the proposed mathematical framework.
This article investigates the impact of thermal radiation considering linear, non-linear, and quadratic effects for a polar fluid influenced by the imposed magnetic field passing through a porous medium with a combined effect of heat and mass diffusion. The variations of the thermal radiation are studied in detail to consider the higher-order terms from the Taylor series expansion. The proposed problem is written in terms of partial differential equations, following the boundary conditions. The appropriate similarity equations in two variables are utilized to transform the mathematical equations into the ordinary form of differential equations. These equations in two variables are further solved by the Bivariate Spectral Quasi Linearization Technique (BSQLM) in MATLAB for the visualization and study of the behavior of the proposed model for the prominent parameters for their velocity, temperature, and concentration profile for all three considered cases. The values of engineering interest quantities are also included to reflect their characteristics for key parameters.
Designing composite structures based on reliability criteria presents a significant challenge, primarily due to the uncertainty of various parameters. This study addresses this issue by investigating the impact of uncertainty in the properties of carbon epoxy composites on the stresses experienced by a perforated plate. The research also explores how the number of experimental test samples and the distribution considered for the composite material properties affect the reliability index. This investigation involved increasing the number of experimental test samples from 5 to 200 and developing a finite element model for the perforated plate. To enhance the data set, neural network methods and the response surface method were employed to create a surrogate model. These data were then used to establish a posterior distribution using Bayesian inference and the Markov chain Monte Carlo method. The limit state function employed is based on the Tsai-Wu criterion. The findings of this research suggest that enhancing the data set smoothens the probability density distribution diagram of the composite material properties, thereby enabling a more accurate estimation of the reliability index.
This study demonstrates the advantages of the multi-layer moving plate method (MMPM) in dynamics analysis of a pavement structure under a moving system on Pasternak foundation. Specifically, the method is utilized to analyze the dynamic behaviors of a pavement structure subjected to a moving single degree of freedom (SDOF) system. The pavement structure is made up of a multilayer plate based on Mindlin's theory and placed on the Pasternak foundation. In addition, the equations that describe the motion of both the SDOF model and the multilayer plate are derived based on a combination of D'Alembert's principle and the principle of virtual work. This study investigates plate deformations and internal forces by examining key parameters, including the mass of the moving SDOF system, plate thicknesses, and Pasternak foundation properties. These analyses identify critical factors affecting the dynamic behavior of pavement structures. The MMPM is further employed to compute internal moments, including longitudinal and transverse bending moments as well as torsional moments, which have not been addressed in previous studies. The reliability of the proposed method is verified through comparisons of plate deflections with other numerical approaches. Additionally, the results present displacement and internal forces through tables and charts across various cases.
Accurate and efficient simulation of heat transfer in materials is crucial for many engineering and industrial applications, but there is still a need to improve thermal modeling methods. This paper presents a quasi-local peridynamic approach for thermal analysis. The spatial response uses peridynamic theory, and the temperature changes over time are calculated with a finite difference method. A new interaction layout is introduced: each particle communicates with only fourteen neighbors in 3D (and four in 2D), regardless of the horizon size. This design greatly improves stability and keeps the computational effort low without losing the advantages of peridynamics in handling discontinuities and heterogeneous materials. Numerical results show that a 3D problem with 5,000 particles and 10,000 time steps can be completed in 4.88 s, with an average cost of 97.6 ns per step and particle. The proposed approach can efficiently simulate complex 2D and 3D heat transfer problems, such as those involving composites, cracked materials, and transient heating or cooling processes.
This work presents a phase-field framework for hydrogen-induced failure that captures the coupled effects of mechanical deformation, crack propagation, and hydrogen diffusion. A staggered solution scheme is adopted, wherein displacement, crack phase-field, and hydrogen concentration are solved sequentially. The framework incorporates a penalty-based moving concentration boundary condition to model hydrogen ingress along propagating cracks. The model is validated through benchmark simulations of an edge-cracked square plate. Stress-assisted diffusion is examined under both tensile and mixed loading conditions. The results demonstrate hydrogen-assisted embrittlement, with increasing initial hydrogen concentration reducing fracture resistance, as reflected in the load-displacement response. The comparison of results under constant and moving concentration boundaries demonstrates their impact on diffusion and fracture behavior. The implementation is carried out in ABAQUS using a user-defined element (UEL) subroutine for solving the coupled equations, while UVARM is employed for state-variable updates and post-processing.
In the study of hydraulic reciprocating rod seals, the prediction of their sealing performance presents challenges in solving the soft elastohydrodynamic lubrication (EHL) problems due to the strong coupling between the hydrodynamic lubrication of the fluid and the finite deformation of the seal, as well as the nonlinear behaviors of the fluid. This paper develops a novel FEM-based mass conserving nonlinear hydrodynamic interface element (MCNL-HIE) to resolve the strongly coupled EHL problems through a monolithic finite element framework. The mass conservation and nonlinear properties of fluid are taken into account to accurately capture the hydrodynamic lubrication behavior of the fluid. In contrast to existing HIEs, no additional nodes or degrees of freedom are introduced in the proposed HIE, thus reducing memory requirements and improving the computation efficiency. Moreover, when dealing with the fluid cavitation problem, no artificial regularization parameters are required, thereby enabling accurate calculation of flow rates. In numerical examples, comparison studies are conducted to demonstrate the accuracy and efficiency of the proposed HIE. EHL simulations of a step-combined rod seal are performed to investigate the influence of fluid cavitation, compressibility and piezoviscous effects on lubrication characteristics and flow rates. Results indicate that unreasonable simulation results are generated when the fluid mass conservation cavitation model is not considered. The seal leakage could be underestimated under high-pressure conditions when fluid compressibility and piezoviscosity are not taken into consideration.
Tensegrity structures are prestressed truss-like structures that balance tensile and compressive forces within a network of struts and cables. They have gained significant attention in engineering and architecture due to their favorable attributes, such as deployability, aesthetic appeal, non-linear behavior, tunable stiffness, and minimal material usage. Researchers have focused most of their work on form-finding methods such as force density, adaptive force density, dynamic relaxation, and evolutionary algorithms. In this research work, the objective is to determine bistable/multistable configurations in a class of symmetric tensegrity structures (class-1symmetrical simplex tensegrity). The bistability or multistability of tensegrity structures, which enables seamless transitions between different shapes and states, can provide optimal performance for a variety of tasks. This research explores optimizing potential energy without using any nonlinear incremental finite element like methods. Instead, this study utilizes an existing commercially available minimization function for non-linear optimization to trace the potential energy curve and determine stable configurations. It is found that the transitions in the lower-order tensegrity structures are twinning-like transitions with the abrupt release of strain energy, while higher-order structures tend to exhibit smooth transitions between two different stable configurations with different energy levels.
In the field of artificial intelligence and machine learning, physics-informed neural networks (PINNs) have received considerable attention because of their extensive applications in flow problems. PINN is a highly effective tool for discovering the intrinsic physics behind transport phenomena by incorporating governing equations into the training procedure of the neural network. The system of nonlinear partial differential equations is developed using non-Newtonian Casson fluid over a cylinder under the effect of a magnetic field in a porous medium. TensorFlow was employed to create and train the models, and the predicted results were compared with the reference solutions using the bvp4c method. This study compared the numerical and predicted solutions for parameter variation. The desired solutions were obtained by extending the parameter values, which required more neurons and hidden layers. To examine the prediction with PINNs, we used four number of hidden layer and three two number of neurons in the PINN design. In addition, the infinite boundary condition requires a suitable number of layers and neurons to be accounted for when the faraway boundary is set at a larger distance from the origin. The variations of various parameters are analyzed on flow output, i.e. velocity and temperature profiles. The interesting of Lorentz force is examined on fluid velocity and heat transfer analysis. It is noted Lorentz force have opposing effects on velocity. It is also noted that with the growing value of thermal radiation results in the increment of heat transfer.
Transonic/supersonic cavity flows exhibit complex fluid dynamics phenomena, such as oscillating shear-layers, flow recirculation, boundary-layer separation, shock/shock and shock/boundary-layer interactions. Computing and characterizing these unsteady flow features have been challenging tasks both experimentally and computationally. The computational prediction of these complex flow phenomena is associated with high-computational cost and thus, computational methods such as large-eddy simulation (LES) and direct numerical simulation (DNS) approaches are not suitable. Therefore, to overcome the computational limitations posed by the DNS and LES approaches, we propose an improved delayed detached-eddy simulation (IDDES) approach for the numerical computation of transonic/supersonic flows. The study shows that IDDES is a suitable, cost-effective and accurate approach for the numerical computation of high-speed turbulent flows. The analysis of the flow physics reveals that the boundary-layer detachment generates a shear-layer which undergoes significant oscillations due to its interaction with the recirculation region inside the cavity. The oscillating shear-layer spans between the fore and rear walls of cavity, and it impinges on the rear-wall of the cavity causing acoustics waves which propagate toward the fore-wall. The cavity causes a flow deceleration from transonic/supersonic flow regimes to subsonic flow regime, and this ensures the combustion stability and flame stabilization. The study also reveals that there is an increase of pressure, temperature and density, with the increase of Mach number. An increase of flow separation with the Mach number was also observed, while the flow separation through the ejection of the boundary-layer causes a decay of the wall temperature.
In the present research, we have investigated the phenomena related to the heat and mass transfer within a steady flow of nanoblood containing penta hybrid nanoparticles. These nanoparticles are engineered with five distinct functional components confined between two parallel sheets of a vertical arterial channel. Here we have considered a uniform magnetic field as a contributing factor. By similarity substitutions, the model equations expressed as partial differential equations are converted into non-linear ordinary differential equations. The numerical solution of the highly non-linear equations is obtained by using Runge-Kutta-Fehlberg method with the shooting scheme. The analysis comprehensively evaluates various critical parameters such as viscosity coefficient, Casson flow parameter, Hartmann number, thermophoretic parameter, Brownian parameter etc. Computational for the variation in primary velocity, secondary velocity, temperature, concentration, Nusselt number and Sherwood number are presented in graphical/tabular. An increase in wall squeezing intensity enhances the axial flow while diminishing the transverse motion, whereas the Lorentz force exhibits an opposite trend. Greater thermal diffusivity reduces temperature but enriches species concentration, showing dual behavior in heat and mass transfer rates. Higher mass diffusivity weakens concentration levels yet maintains duality in mass transfer characteristics. Enhanced fluid viscosity promotes axial momentum, suppresses secondary flow, lowers temperature, and intensifies species concentration, further highlighting the dual nature of thermal and solutal transport. Overall, the effects of various parameters are comprehensively discussed, revealing that the penta-hybrid nanoblood significantly influences the velocity, heat, and mass transfer characteristics along with the Nusselt and Sherwood numbers.
Rodents budge their whiskers to explore their environment, using the follicle sinus complex at the base to sense elastic deformation. We designed the Sphar-Whisker sensor to mimic this mechanism. The sensor combines a carbon fiber whisker with a fluid-filled bubble inside an elastomer, enabling precise spatial force detection. We modeled the whisker with Euler-Bernoulli beam theory and determined the bubble's transfer function experimentally. COMSOL FEA simulations showed how the bubble deforms under static and dynamic loads. The mathematical model and simulation are validated through experiment using UR3e serial manipulator. We tested the sensor using laser vibrometer while scanning a 50-mu m surface generated from turning, and vertical and horizontal milling. The combined system response exhibits resonance at 4.11 and 527.6 Hz with respect to the soft elastomer and the whisker respectively. The simulation also revealed similar low- and high-frequency resonances at 133 Hz and 751 Hz, respectively. The Sphar-Whisker can map 3D deformations and distinguish surface textures. Future work will use the arrays of whiskers and bubbles for advanced texture analysis with active, closed-loop sensing.
Geothermal energy piles are an innovative and environmentally alternative option than conventional piles, which only provide structural support. Encouragingly, these Geothermal energy piles are renewable and sustainable because they not only support buildings but also use the earth's inherent low-grade heat for space heating and cooling. The challenge facing this fascinating area of geotechnical engineering is the need for in-depth understanding of how these piles respond to mechanical and thermal loading. This study investigates the thermo- mechanical behavior of energy piles subjected to single and multiple thermal cycles using the finite element program ABAQUS CAE 2017. The pile was modeled with a linear elastic approach, while the soil was represented using the Mohr-Coulomb model.
This study presents a numerical analysis of natural and combined thermocapillary-buoyant convection in two-dimensional semi-circular enclosures filled with copper-water nanofluids. A local meshless method based on radial basis functions (RBF) is employed to solve the governing equations, eliminating the need for mesh generation and offering enhanced adaptability to complex geometries. The investigation spans a broad range of Rayleigh numbers (103-105), Marangoni numbers (0-1000), and nanoparticle volume fractions (up to 0.05). The results demonstrate that increasing the Rayleigh number significantly strengthens fluid motion and enhances thermal transport, as evidenced by higher stream function and Nusselt number values. The addition of nanoparticles yields a modest improvement in heat transfer efficiency. Furthermore, elevated Marangoni numbers intensify surface-tension-driven flows, leading to substantial increases in convective activity and thermal performance. The principal contribution of this work lies in the novel application of a meshless RBF framework to simulate coupled buoyancy- and thermocapillary-driven flows in curved domains, providing a flexible and accurate method for analyzing nanofluid-based thermal systems.
The present work investigates the application and optimization of exponential finite element (EFE) shape functions in phase-field modeling of fracture in orthotropic functionally graded materials (FGMs), which present challenges due to their combined anisotropy and spatially varying properties. While EFE shape functions offer improved accuracy in capturing steep stress gradients and complex crack patterns, their use typically involves a high computational cost due to dense numerical integration requirements. This study addresses this limitation by systematically optimizing the integration point density required for accurate and efficient EFE-based simulations. Two benchmark classes of problems are considered: (i) an L-shaped panel specimen exhibiting mixed-mode crack propagation, and (ii) edge-cracked orthotropic FGMs with varying material orientations and gradation patterns. Through these examples, we explore the tradeoff between solution accuracy and computational cost, comparing EFE performance against standard linear finite elements (LFE) and high-resolution reference solutions. Notably, this is the first study to apply EFE shape functions in the context of orthotropic fracture modeling. The results establish both the viability of EFEs for such complex materials and the effectiveness of an adaptive integration strategy, thereby making EFE-based phase-field models more computationally practical for real-world applications.
