Applied and Computational Mechanics

Circulation control technology and motion in close proximity to the ground have both shown aerodynamic benefits in the generation of lift. Recent research efforts at West Virginia University have explored the potential of merging the two phenomena, in an attempt to enhance both technologies. This paper initiates this combined effort by experimentally investigating the impact ground effect has on the separation location of a jet blown tangentially over circulation controlled cylindrical surfaces. Previous experimental research on circulation controlled cylinders found an optimal radius of curvature and volumetric flow rate; whose model and optimal findings are built upon by this work through the addition of ground effect analysis by varying the ground height. The experiment investigates some of the variables that individually influence circulation control and ground effect; the variables are the radius of curvature, velocity of the jet, and the height from the ground. Data analysis revealed that for a constant volumetric flow rate and varying the height to radius (h/r) value, there is a large amount of variability in the data, indicating that the proximity of the ground has significant impact on the separation location and consequently influence on the potential lift characteristics. Furthermore, when this flow rate was analyzed, it was found that at an h/r of approximately 4.8, it appears that an optimal h/r occurs, based on the surface pressure and flow separation from the cylinders when not influenced by the ground. The data also found that at both radii, 0.520 and 0.659 inches, showed benefit when tested in close proximity to the ground. The findings demonstrate that there is further enhancement potential of the lift generating capability by uniting the lift enhancement of circulation control methodology with the ground effect flight regime. This effort is a preliminary study of a larger effort to determine if merging the two phenomena indicates a lift enhancement. This model does not have a free stream velocity, and subsequently does not measure

The relatively efficient and accurate Adomian modified decomposition method (AMDM) is used in this paper to investigate the free vibrations of Euler-Bernoulli beams, with a single section discontinuity present, and resting on a two-parameter elastic foundation. This work develops a fast and accurate method of calculation, with the ability to change boundary conditions easily. Analytical calculations are presented for natural frequencies and associated mode shapes, which are compared with experimental and calculated results found by experimental and other calculation methods reported in the literature.

Engine mounting bracket plays very significant role in reducing noise, vibration and harshness caused due to engine and thus has very effective role in improving vehicle comfort. This current work accounts for the investigation of engine mounting bracket by using hyper mesh and Optistruct approach. Static analysis of engine mounting bracket was done in order to check design of existing and modified bracket. The results were analyzed for stresses and deformations. The design was tested for different design of Mild Steel with different thickness. From Design and analysis, it is considered that stresses induced in the bracket were 260.00 Mpa and deformation 9.6 mm. It can be anticipated that modified brackets can be considered for desired application.

In the present article, surface wave propagation of moisture diffusion, temperature and elastic waves is discussed in a hygrothermoelastic medium. The coupled wave equations obtained in terms of moisture concentration, displacement and temperature are solved using surface wave solutions. On solving these equations, we get the values of penetration depths of different waves involved in this problem. These values are represented graphically against frequency. As a special case, the components of displacement, stresses and moisture concentration in the medium are also obtained and presented graphically, when a mechanical force is applied along the free surface of the hygrothermoelastic medium.

This paper is devoted to the decomposition of an image f into u + v, with u a piecewise-smooth or "cartoon" component, and v an oscillatory component (texture or noise), in a variational approach. Y. Meyer [Y. Meyer, Oscillating Patterns in Image Processing and Nonlinear Evolution Equations, University Lecture Series, vol. 22, Amer. Math. Soc., Providence, RI, 2001] proposed refinements of the total variation model [L. Rudin, S. Osher, E. Fatemi, Nonlinear total variation based noise removal algorithms, Phys. D 60 (1992) 259-268] that better represent the oscillatory part v: the weaker spaces of generalized functions G = div(L ∞ ), F = div(BMO), and E = Ḃ-1 ∞,∞ have been proposed to model v, instead of the standard L 2 space, while keeping u ∈ BV, a function of bounded variation. Such new models separate better geometric structures from oscillatory structures, but it is difficult to realize them in practice. D. Mumford and B. Gidas [D. Mumford, B. Gidas, Stochastic models for generic images, Quart. Appl. Math. 59 (1) (2001) 85-111] also show that natural images can be seen as samples of scale invariant probability distributions that are supported on distributions only, and not on sets of functions. In this paper, we consider and generalize Meyer's (BV, E) model, using the homogeneous Besov spaces Ḃα p,q , -2 < α < 0, 1 p, q ∞, to represent the oscillatory part v. Theoretical, experimental results and comparisons to validate the proposed methods are presented.

There is a requirement to find accurate parameters to accomplish precise dimensional accuracy, excellent surface integrity and maximum MRR. This work studies the influence of various cutting parameters on output parameters like Cutting force, Surface roughness, Flatness, and Material removal rate while face milling. A detailed finite element model was developed to simulate the face milling process. The material constitutive behavior is described by Johnson-Cook material model and the damage criteria is established by Johnson-Cook damage model. The result indicate significant effects of all three cutting parameters on MRR and both feed rate and depth of cut have significant effect on cutting force. Also, feed rate has significant effect on PEEQ and none of the parameters have effect on flatness.

This paper presents a study on optimization of process parameters using particle swarm optimization to minimize angular distortion in 202 grade stainless steel gas tungsten arc welded plates. Angular distortion is a major problem and most pronounced among different types of distortion in butt welded plates. The process control parameters chosen for the study are welding gun angle, welding speed, plate length, welding current and gas flow rate. The experiments were conducted using design of experiments technique with five factor five level central composite rotatable design with full replication technique. A mathematical model was developed correlating the process parameters with angular distortion. A source code was developed in MATLAB 7.6 to do the optimization. The optimal process parameters gave a value of 0.0305° for angular distortion which demonstrates the accuracy of the model developed. The results indicate that the optimized values for the process parameters are capable of producing weld with minimum distortion.

I hereby certify that, to the best of my knowledge, the thesis entitled 'Strength Predictions of Hat Stiffened Plate Using Finite Element Method' submitted by Manoj G. Tharian, Part time research student, Reg. No. 3562, to Cochin University of Science and Technology in partial fulfillment of the requirement for the award of Ph.D. degree in the faculty of technology is a bonafide record of the research work carried out by him under my supervision and guidance. The contents of this thesis have not been submitted to any other university or institute for the award of any degree. I also certify that all the relevant corrections and modifications suggested by the audience during the pre-synopsis seminar and recommended by the Doctoral Committee of the candidate have been incorporated in the thesis.

In this paper, we build a multidimensional wavelet decomposition based on polyharmonic B-splines. The prewavelets are polyharmonic splines and so not tensor products of univariate wavelets. Explicit construction of the filters specified by the classical dyadic scaling relations is given and the decay of the functions and the filters is shown. We then design the decomposition/recomposition algorithm by means of downsampling/upsampling and convolution products.

This research investigates hemodynamic behavior in stenosed arteries using a rheological model that integrates hybrid nanoparticles (copper and graphene) suspended in blood. A mathematical framework is developed to analyze flow dynamics in an inclined artery with mild stenosis, incorporating electromagnetic fields, Hall currents, heat generation, and porous media effects governed by Darcy's law. Simplifications under mild stenosis and low Reynolds number conditions enable analytical solutions via the homotopy perturbation method (HPM) and Akbari Ganji Method (AGM). The minimal error observed for axial velocity is 2.34 × 10-10 , while that for temperature is 8.87 × 10-10. Key findings reveal that hybrid nanoparticle enrichment reduces blood flow resistance, and elevated Hall parameters significantly decrease wall shear stress at the arterial boundary. Additionally, an increase in the Darcy number leads to higher axial velocity in all cases. Streamline visualizations demonstrate altered flow patterns in stenosed regions under varying nanoparticle volumes and electromagnetic inputs. Notably, Hall currents exert a pronounced influence on nanoparticle-enhanced flow behavior, underscoring their relevance in biomedical contexts. The efficacy of HPM and AGM in resolving nonlinear momentum equations is validated, supporting their utility in modeling complex bionanofluid systems. These insights advance applications in targeted drug delivery, bio-nanofluid mechanics, and therapeutic device design. They offer pathways for optimizing nanoparticle-mediated treatments in cardiovascular diseases and oncology.

Analytical solutions of differential equations provide exact representations of physical phenomena, enhance computational efficiency, and offer deeper theoretical insights than purely numerical approaches. In mathematical physics, such solutions are essential for uncovering fundamental laws, accurately predicting system behavior, and developing closed-form expressions that drive further theoretical advancements and physical interpretations. However, the complexity of real-world differential equations-with their inherent nonlinearities, variable coefficients, and intricate boundary conditions-often precludes the attainment of exact analytical solutions, resulting in the predominance of numerical methods that offer computational feasibility albeit at the cost of precision. This study aims to overcome these limitations by employing the hybrid analytical and numerical method (HAN method) to derive an analytical solution for the nonlinear differential equation (NDE) governing Jeffery-Hamel flow. Initially, numerical solutions of the governing equations are obtained to construct a comprehensive dataset, which, together with the boundary conditions, facilitates the extraction and formulation of an exact analytical solution. This HAN method effectively upgrades numerical approximations into analytical forms, thereby bridging the gap between computational practicality and theoretical rigor in the analysis of complex NDEs.

Over the last decades, in the field of control engineering, Model Predictive Control (MPC) has been successfully ‎employed in many industrial processes. This due to, among other aspects, its capability to include constrains within ‎the design control formulation and also its ability to perform on-line optimization. For instance, in the civil ‎engineering field, different MPC approaches have been well developed to formulate active control algorithms able ‎to reduce civil structural responses to earthquakes. Thus, in this paper, a customized version of a conventional ‎Predictive Control (PC) strategy is proposed to mitigate the displacement on a base-isolated system with a ‎nonlinear hysteresis behavior, that is excited by a seismic event. The proposal consists of including a dynamic ‎hysteresis system into the control scheme to generate a reference trajectory that will softly drive the base-isolated ‎structure to a rest status. The proposed control scheme is evaluated through numeric...

Inspection and specificity of the intactness of multi-layer and small-size parts like copper-clad steel rod is a hard task and requires high accuracy. The intactness of these parts is crucial due to their importance. One of the inspection methods for these parts is using ultrasonic waves. The scattering phenomenon occurs when these waves impact curved shape bodies under a special condition. The ultrasonic scattering waves contain a lot of information from the physical conditions and mechanical properties of the part. However, using these waves requires high accuracy and attention due to their complexity. One result of the ultrasonic scattering waves is the far-field backscattered frequency spectrum, form function. For the first time in this research, the form function of a copper-clad steel rod that is immersed in water is calculated using the finite element method (FEM) available in the commercial ABAQUS software. For validating the proposed model, the simulation results are compar...

In this paper we present a super resolution Bayesian methodology for pansharpening of multispectral images. By following the hierarchical Bayesian framework, and by applying variational methods to approximate probability distributions this methodology is able to: a) incorporate prior knowledge on the expected characteristics of the multispectral images, b) use the sensor characteristics to model the observation process of both panchromatic and multispectral images, c) include information on the unknown parameters in the model in the form of hyperprior distributions, and d) estimate the parameters of the hyperprior distributions on the unknown parameters together with the unknown parameters, and the high resolution multispectral image. Using real data, the pansharpened multispectral images are compared with the images obtained by other parsharpening methods and their quality is assessed both qualitatively and quantitatively.

Large-eddy simulations and full-scale investigations were carried out that aimed to reduce the aerodynamic drag and thus the fuel consumption of trucktrailers. The computational model is a relevant generic truck-trailer combination, and the full-scale is a corresponding Volvo prototype vehicle. Passive and active flow control (AFC) approaches were adopted in this work and applied at the rear end of the trailer. Flaps were mounted at an angle that induces separation, and synthetic jet actuators were placed close to the corner of the rear end and the flaps. The drag reduction obtained is in the order of 30%. The flow was analyzed by comparing the phase-averaged and time-averaged flow field of the unforced and the forced cases. The full-scale prototype is a Volvo truck-trailer. The trailer is mounted by three flaps at the rear sides and top end. The actuators consist of loudspeakers in sealed cavities, connected to amplifiers that are supplied with a frequency generator controlled by LabVIEW. The full-scale test includes passive and active flow control investigations by varying the flap angle, with and without AFC, investigating different frequency and slot angle configurations. The fuel flux was measured during the full-scale test. The test shows a fuel reduction of about 4% in a comparison of two flap angles. The test of active flow control shows a reduction of 5.3% compared to the corresponding unforced case. Compared with the baseline case, the passive flow control fails to reduce the total fuel consumption.

Preliminary experiments were carried out to investigate possible benefits of using a relatively new type of fluidic actuators (Raman & Raghu [1]) in combination with attached aft bodies to reduce the drag on a standard semi-trailer truck. The actuators generate oscillating jets that cause the formation of streamwise vortices that enhance the entrainment of the shear layer significantly. Taking into account the potential feasibility of any add-ons to a trailer, seven different bodies with simple geometries were chosen for this investigation. A a total open area of actuator nozzles A cs cross section of trailer, based on total height L c circumference of trailer U j actuators jet velocity, based on flow rate U ∞ free stream velocity ρ density of air baseline configuration (no actuation) D hydr = 4*A cs /L c hydraulic diameter Re Reynolds number, based on D hydr

In this paper, we present a theoretical study of the combined effects of activation energy and binary chemical reaction in an unsteady mixed convective flow over a boundary of infinite length. The current study incorporates the influence of the Brownian motion, thermophoresis and viscous dissipation on the velocity of the fluid, temperature of the fluid and concentration of chemical species. The equations are solved numerically to a high degree of accuracy using the spectral quasilinearization method. Brownian motion was noted as the main process by which the mass is transported out of the boundary layer. The effect of thermophoretic parameter seems to be contrary to the expected norm. We expect the thermophoretic force to ‘push’ the mass away from the surface thereby reducing the concentration in the boundary layer, however, concentration of chemical species is seen to increase in the boundary layer with an increase in the thermophoretic parameter. The use of a heated plate of infi...

In this paper, we will first study the existence and uniqueness of the solution for a one dimensional Inverse Heat Conduction Problem (IHCP) via an auxiliary problem. Then a stable numerical method consists of the zeroth-, first-and second-order Tikhonov regularization method to the matrix form of Duhamel's principle for solving this IHCP by using noisy data is presented. The inverse problem has a unique solution, but this solution is unstable hence the problem is ill-posed. This instability is overcome using the Tikhonov regularization method with the gcv criterion for the choice of the regularization parameter. The stability and accuracy of the scheme presented is evaluated by comparison with the Singular Value Decomposition (SVD) method.

In this paper, the effect of different boundary conditions on the free vibration analysis response of a sandwich plate is presented using the higher order shear deformation theory. The face sheets are orthotropic laminated composites that follow the first order shear deformation theory (FSDT) based on the Rissners-Mindlin (RM) kinematics field. The motion equations are derived considering the continuity boundary conditions between the layers based on the energy method and Hamilton&#39;s principle. The frequency and mode shapes of the structure are obtained using the differential quadrature method (DQM). The effects of different parameters such as the face sheet-to-core stiffness ratio, the boundary conditions, and the core-to-face sheet thickness ratio on the frequency of the sandwich plate are shown. Moreover, the numerical results indicate that the frequency of the CCCC and CFFF sandwich plates predict the higher and lower frequency, respectively.

Purpose– Analysis of non-prismatic beams has been focused of attention due to wide use in complex structures such as aircraft, turbine blades and space vehicles. Apart from aesthetic aspect, optimization of strength and weight is achieved in use of this type of structures. The purpose of this paper is to present new shape functions, namely 3-node Basic Displacement Functions (BDFs) for derivation of structural matrices for general non-prismatic Euler-Bernoulli beam elements. Design/methodology/approach– Static analysis and free transverse vibration of non-prismatic beams are extracted studied from a mechanical point of view. Following structural/mechanical principles, new static shape functions are in terms of BDFs, which are obtained using unit-dummy-load method. All types of cross-sections and cross-sectional dimensions of the beam element could be considered in this method. Findings– According to the outcome of static analysis, it is verified that exact results are obtained by ap...

The Rajendran-Grove (RG) ceramic damage model is a three-dimensional internal variable based constitutive model for ceramic materials, with the considerations of micro-crack extension and void collapse. In the present paper, the RG ceramic model is implemented into the newly developed computational framework based on the Meshless Local Petrov-Galerkin (MLPG) method, for solving high-speed impact and penetration problems. The ability of the RG model to describe the internal damage evolution and the effective material response is investigated. Several numerical examples are presented, including the rod-on-rod impact, plate-on-plate impact, and ballistic penetration. The computational results are compared with available experiments, as well as those obtained by the popular finite element code (Dyna3D).

Surface roughness is known to have great influence on fatigue life. The traditional approach is to relate the average roughness to the endurance life through a material parameter such as ultimate tensile strength. Such approaches have however shown a large degree of scatter, indicating that this approach is insufficient for relating surface topography to fatigue strength. This is the motivation for the current research, where surface roughness is modelled by finite elements obtained from measured topography. The results can be used directly in fatigue life prediction or as a foundation for evaluating and developing prediction methods. An aluminium alloy used in a wrought automotive front wheel suspension arm is used for testing and evaluation.

In this paper, we apply a new method for solving system of partial differential equations within local fractional derivative operators. The approximate analytical solutions are obtained by using the local fractional Laplace variational iteration method, which is the coupling method of local fractional variational iteration method and Laplace transform. Illustrative examples are included to demonstrate the high accuracy and fast convergence of this new algorithm. The obtained results show that the introduced approach is a promising tool for solving system of linear and nonlinear local fractional differential equations. Furthermore, we show that local fractional Laplace variational iteration method is able to solve a large class of nonlinear problems involving local fractional operators effectively, more easily and accurately; and thus it has been widely applicable in physics and engineering.

This study investigates the effects of internal heat generation, radiation, and viscoelasticity on the convective flow of a biofluid through a deformable porous medium. Flow through a deformable porous medium is essential in a lot of physiological systems involving soft tissues; for instance, coronary blood flows through arteries with arteriosclerosis. Deformability occurs in systems that allow flows with highly viscous pressure force through elastic porous materials. Based on this assumption, a new mathematical model for the nonlinear convective flow for high temperature difference is formulated. In this regard, this investigation addresses the steady internal heat generation, radiation, and viscoelasticity on the convective flow of a biofluid through a deformable porous medium. The governing equations are formulated for the solid displacement, flow velocity and energy equations based on fully developed flow assumptions and one-directional flow within the impervious vertical walls. The dimensionless version of the governing equations is solved based on the Spectral Chebyshev Collocation procedures and validated by the fourth-order Shooting-Runge-Kutta Scheme. In the limiting case, the Spectral Quasilinearization method is applied and used for validation with the existing literature work. Graphical results are displayed to explain the effects of each flow parameter. The results demonstrate that internal heat generation enhances fluid velocity and temperature, while the viscoelastic characteristics and deformability of the porous medium critically affect flow dynamics.

This study investigates the effects of internal heat generation, radiation, and viscoelasticity on the convective flow of a biofluid through a deformable porous medium. Flow through a deformable porous medium is essential in a lot of physiological systems involving soft tissues; for instance, coronary blood flows through arteries with arteriosclerosis. Deformability occurs in systems that allow flows with highly viscous pressure force through elastic porous materials. Based on this assumption, a new mathematical model for the nonlinear convective flow for high temperature difference is formulated. In this regard, this investigation addresses the steady internal heat generation, radiation, and viscoelasticity on the convective flow of a biofluid through a deformable porous medium. The governing equations are formulated for the solid displacement, flow velocity and energy equations based on fully developed flow assumptions and one-directional flow within the impervious vertical walls. The dimensionless version of the governing equations is solved based on the Spectral Chebyshev Collocation procedures and validated by the fourth-order Shooting -Runge-Kutta Scheme. In the limiting case, the Spectral Quasilinearization method is applied and used for validation with the existing literature work. Graphical results are displayed to explain the effects of each flow parameter. The results demonstrate that internal heat generation enhances fluid velocity and temperature, while the viscoelastic characteristics and deformability of the porous medium critically affect flow dynamics.

An optimal algorithm is described for solving the deconvolution problem of the form ku := ∫ t 0 k(t − s)u(s)ds = f(t) given the noisy data fδ, ||f − fδ|| ≤ δ. The idea of the method consists of the representation k = A(I+S), where S is a compact operator, I + S is injective, I is the identity operator, A is not boundedly invertible, and an optimal regularizer is constructed for A. The optimal regularizer is constructed using the results of the paper MR 40#5130.

A study on heat and mass transfer of a steady laminar boundary layer flow of an electrically conducting fluid of second grade in a porous medium subject to a uniform magnetic field past a semi-infinite stretching sheet with power law surface temperature or power law surface heat flux. The variations in fluid velocity, fluid temperature and species concentration are displayed graphically whereas the numerical values of skin friction, Nusselt number and Sherwood number are presented in tabular form for various values of the pertinent flow parameters. The asymptotic expansions of the solutions for large Prandtl number are also given for the two heating conditions. The temperature distribution decreases with the increase in thermal radiation parameter in case of PST and PHF. The rate of mass transfer at the solid surface increases in the presence of magnetic field and decreases with heavier diffusing species.  

The relatively efficient and accurate Adomian modified decomposition method (AMDM) is used in this paper to investigate the free vibrations of Euler-Bernoulli beams, with a single section discontinuity present, and resting on a two-parameter elastic foundation. This work develops a fast and accurate method of calculation, with the ability to change boundary conditions easily. Analytical calculations are presented for natural frequencies and associated mode shapes, which are compared with experimental and calculated results found by experimental and other calculation methods reported in the literature.

research in the field of biomechanics related to orthopedic implants is rapidly growing in the world, especially for fixation of fractured bone. Fixation is a surgery to locate and attach a plate pressed by screws at the fractured bone. Most of the fracture bones sited in femur. This research focuses on modeling and simulation of plate and screw made of SS316L material for the fixation of the fractured femur using finite element method (FEM). SS316L is a material with good biocompatibility, cheap, and ductile enough. Modeling and simulation done using ANSYS 15.0 software. Simulation results are stress, strain, and total deformation. It is obtained that optimum diameter of screw is 4.5 mm with respect to minimum value of von Mises stress and deformation.

The presence of cracks causes changes in the physical properties of a structure which introduces flexibility,and thus reducing the stiffness of the structure with an inherent reduction in modal natural frequencies. Consequently it leads to the change in the dynamic response of the beam. This paper focuses on the theoretical analysis of transverse vibration of a fixed beam and investigates the mode shape frequency. All the theoretical values are analyzed with the numerical method by using ANSYS software and co relate the theoretical values with the numerical values to find out percentage error between them.Also in this paper, a model for free vibration analysis of a beam with an open edge crack has been presented. Variations of natural frequencies due to crack at various locations and with varying crack depths have been studied. A parametric study has been carried out. The analysis was performed using ANSYS software.

Let ρ be an unknown Borel measure defined on the space Z := X × Y with X ⊂ IR d and Y = [-M, M ]. Given a set z of m samples z i = (x i , y i ) drawn according to ρ, the problem of estimating a regression function f ρ using these samples is considered. The main focus is to understand what is the rate of approximation, measured either in expectation or probability, that can be obtained under a given prior f ρ ∈ Θ, i.e. under the assumption that f ρ is in the set Θ, and what are possible algorithms for obtaining optimal or semi-optimal (up to logarithms) results. The optimal rate of decay in terms of m is established for many priors given either in terms of smoothness of f ρ or its rate of approximation measured in one of several ways. This optimal rate is determined by two types of results. Upper bounds are established using various tools in approximation such as entropy, widths, and linear and nonlinear approximation. Lower bounds are proved using Kullback-Leibler information together with Fano inequalities and a certain type of entropy. A distinction is drawn between algorithms which employ knowledge of the prior in the construction of the estimator and those that do not. Algorithms of the second type which are universally optimal for a certain range of priors are given.

The work in volves as sess ing of the ma rine cur rent re gime in the north west of the Black Sea, Midia Cape-Constanta area. The area of in ter est is cho sen due its ex isting fea tures, us ing ma rine cur rents data (di rec tion and speed) within the CFD to de ter mine the dis tri bu tion of ve loc i ties and pres sures. The study on the dis tri bu tion of ve loc i ties and pres sures, ac cord ing to lo cal hy dro-me te o ro log i cal char ac ter is tic el e ments, can be used for iden ti fy ing the risk ar eas for nav i ga tion and ex ist ing hydro-tech ni cal con struc tion in dus try. Mod el ling re sults us ing the CFD anal y sis shows the cur rents ve loc ity val ues, pres sures and turbulences of the in ves ti gated ma rine re gion. The model can be used in the anal y sis and the coast line changes as well as in risk as sess ment for hy drau lic struc tures. Ad di tional pa ram e ters into the model, such as the sea wave char ac ter is tics, aim to pro vide an in di ca tion of the poten tial hy dro-dy namic power that is avail able at a de ter mined lo ca tion of in ter est.

This paper proposes a finite element method (FEM) based on a nonlocal theory for analyzing the free vibration of the functionally graded porous (FGP) nano-plate with different shapes lying on the elastic foundation (EF). The FGP materials with two-parameter are the power-law index (k) and the porosity volume fraction ( ) in two cases of even and uneven porosity. The EF includes Winkler stiffness (k1) and Pasternak stiffness (k2). Some numerical results in our work are compared with other published to verify accuracy and reliability. Moreover, the influence of geometric parameters, materials on the free vibration of the FGP nano-plates resting on the EF is comprehensively investigated.

In this paper, free vibration analysis of the functionally graded porous (FGP) plates on the elastic foundation taking into mass (EFTIM) is presented. The fundamental equations of the FGP plate are derived using Hamilton’s principle. The mixed interpolation of the tensorial components (MITC) approach and the edge-based smoothed finite element method (ES-FEM) is employed to avoid the shear locking as well as to improve the accuracy for the triangular element. The EFTIM is a foundation model based on the two-parameter Winkler–Pasternak model but added a mass parameter of foundation. Materials of the plate are FGP with a power-law distribution and maximum porosity distributions in the forms of cosine functions. Some numerical examples are examined to demonstrate the accuracy and reliability of the proposed method in comparison with those available in the literature.

Additive manufacturing (AM) technologies such as fused deposition modeling (FDM) rely on the quality of manufactured products and the process capability. Currently, the dimensional accuracy and stability of any AM process is essential for ensuring that customer specifications are satisfied at the highest standard, and variations are controlled without significantly affecting the functioning of processes, machines, and product structures. This study aims to investigate the effects of FDM fabrication conditions on the dimensional accuracy of cylindrical parts. In this study, a new class of experimental design techniques for integrated second-order definitive screening design (DSD) and an artificial neural network (ANN) are proposed for designing experiments to evaluate and predict the effects of six important operating variables. By determining the optimum fabrication conditions to obtain better dimensional accuracies for cylindrical parts, the time consumption and number of complex e...

Mechanical metamaterials are artificial composites with tunable advanced mechanical properties. Particularly, interesting types of mechanical metamaterials are flexible metamaterials, which harness internal rotations and instabilities to exhibit programable deformations. However, to date, such materials have mostly been considered using nearly purely elastic constituents such as neo-Hookean rubbers. Here, we experimentally explore the mechanical snap-through response of metamaterials that are made of constituents that exhibit large viscoelastic relaxation effects, encountered in the vast majority of rubbers, in particular, in 3D printed rubbers. We show that they exhibit a very strong sensitivity to the loading rate. In particular, the mechanical instability is strongly affected beyond a certain loading rate. We rationalize our findings with a compliant mechanism model augmented with viscoelastic interactions, which qualitatively captures well the reported behavior, suggesting that ...

The algebraic and geometric properties of a novel generalization of Clifford&#39;s classical4point–circle configuration are analysed. A connection with the integrable quaternionic discrete Schwarzian Kadomtsev–Petviashvili equation is revealed.

In this study, a hybrid method is proposed to investigate the nonlinear vibrations of pre- and post-buckled rectangular plates for the first time. This is an answer to an existing need to develope a fast and precise numerical model which can handle the nonlinear vibrations of buckled plates under different boundary conditions and plate shapes. The method uses the differential quadrature element, arc-length, harmonic balance and direct iterative methods. The governing differential equations of plate vibration have been extracted considering shear deformations and the initial geometric imperfection. The solution is assumed to be the sum of the static and dynamic parts which upon inserting them into the governing equations, convert them into two sets of nonlinear differential equations for static and dynamic behaviors of the plate. First, the static solution is calculated using a combination of the differential quadrature element method and an arc-length strategy. Then, putting the fir...

In this paper, a novel approach is proposed to investigate the progressive collapse damage of prismatic thin walled metal columns with different regular cross sections, under the action of axial quasi-static and impact loads. The present work mainly focuses on implementation of some important factors which have been neglected in other studies. These factors include the effect of reducing impactor velocity and inertia effect during collapse, a mixed collapse mode for crushing mechanism, and consideration of a realistic elasto-plastic model for material. Taking all these factors into account, the analysis led to some parametric algebraic equations without a possible general solution in terms of collapse variables. Consequently, a new theoretical approach was proposed based on previously offered Super Folding Element (SFE) theory, to obtain the closed form explicit relations for the static and dynamic mean crushing forces and collapse variables. The proposed approach considers an analy...

Operator splitting is a powerful method for the numerical investigation of complex time-dependent models, where the stationary (elliptic) part consists of a sum of several structurally simpler sub-operators. As an alternative to the classical splitting methods, a new splitting scheme is proposed here, the Average Method with sequential splitting. In this method, a decomposition of the original problem is sought in terms of commuting matrices. Wedemonstrate that third-order accuracy can be achieved with the Average Method. The computational performance of the method is investigated, yielding run times 1-2 orders of magnitude faster than traditional methods.

For solving systems of nonlinear equations, we have recently developed a Newton's method to manage issues with inaccurate function values or problems with high computational cost. In this work we introduce a modification of the above method, reducing the total computational cost and improving, in general, its overall performance. Moreover, the proposed version retains the quadratic convergence, the good behavior over singular and ill-conditioned cases of Jacobian matrix, and its capability to be ideal for imprecise function problems. Numerical results demonstrate the efficiency of the new proposed method.

Since the FGMs are increasingly implemented in the practice of industries, dynamics of cracked structures made of FGM gets an enormous attention of researches and engineers. Also, a number of methods has been proposed to vibration analysis of the structures such as Galerkin's method, Finite Element Method (FEM), Dynamic Stifness Method (DSM), … However, for the simple structures such as beams the analytical approach shows to be most accurate and efficient. Yan et al. ( ) calculated natural frequencies and mode shapes of cracked FGM Euler-Bernoulli beam. Ke et al. (2009) studied effects of open edge cracks to vibration of FGM Timoshenko beam with different

This article concentrates on the effect of MHD heat mass transfer on the stagnation point nanofluid flow over a stretching or shrinking sheet with homogeneous-heterogeneous reactions. The flow analysis is disclosed in the neighborhood of stagnation point. Features of heat transport are characterized with Newtonian heating. The homogeneous-heterogeneous chemical reaction between the fluid and diffusing species is included in the mass diffusion equation. The MHD stagnation boundary layer flow is explored in the presence of heat generation/absorption. Numerical convergent solutions are computed via the spectral quasi-linearization method (SQLM). The physical aspects of different parameters are discussed through graphs.

This work presents a numerical approach in order to predict the influence of implant material stiffness in a femoral component design when submitted in compression. The implant success depends on the transferred load to the neighboring bone. The finite element method can be used to analysis the stress and strain distribution in the femoral component allowing to improve the implant selection. For this purpose, 2D axisymmetric computational models of an implant-cement-bone (Model 1), implant-bone (Model 2) and core implant-bone (Model 3) were constructed using the finite element method with ANSYS program. The finite element model was assumed a state of ideal osseointegration, where the cortical bone, cement and implant were assumed as perfectly bonded. Three different implant diameters were chosen and two materials considered, a typical titanium alloy and iso-elastic titanium alloy with low stiffness. The finite element analysis was carried out to calculate the von Mises stress, the s...

This study investigates the transient magnetohydrodynamic (MHD) flow and heat and mass transfer over an inclined, radiative, and permeable surface under the influence of viscous dissipation and Ohmic heating in a porous medium. A regular perturbation technique is employed to solve the governing coupled, nonlinear partial differential equations that describe the velocity, temperature, and concentration fields. The analysis focuses on key physical parameters, including the skin friction coefficient, Nusselt number, and Sherwood number, along with the corresponding field profiles. The results highlight the significant impact of inclination angle, porosity, and thermal radiation on the transport behavior. Specifically, thermal radiation is found to reduce both the temperature distribution and the Nusselt number, indicating a damping effect on thermal transport. Conversely, the presence of a heat source elevates the temperature while enhancing heat transfer. Additionally, the Soret number contributes to an increase in both temperature and solute concentration due to thermal diffusion effects. The findings correspond well with previously published studies. In other words, when the inclined angle, porous parameter, and radiation parameter are not considered, all outcomes closely resemble those of the previously published works. This study offers valuable insights applicable to various industrial processes, including chemical manufacturing and thermal management systems.

A universal approach by Laplace transform to the variational iteration method for fractional derivatives with the nonsingular kernel is presented; in particular, the Caputo-Fabrizio fractional derivative and the Atangana-Baleanu fractional derivative with the non-singular kernel is considered. The analysis elaborated for both non-singular kernel derivatives is shown the necessity of considering the modified Caputo-Fabrizio fractional derivative and the analogous modifications for the Atangana-Baleanu fractional derivative with non-singular Mittag-Leffler kernel in order to satisfy the initial conditions for some fractional differential equations.

An one-dimensional model to determine the laminar ow of a fluid in a porous channel with wall suction or injection is proposed. The approach is based on the integration of the Navier–Stokes equations using the analytical solutions for the two-dimensional local velocity and pressure fields obtained from the asymptotic developments at low filtration Reynolds number proposed by Berman and Yuan and Finkelstein. It is noticeable that the resulting one-dimensional model preserves the whole low properties, in particular the inertial terms which can affect the wall suction conditions. The model is
validated in the case of a single porous channel of rectangular or circular cross-section with uniform or variable wall suction. Then the model is applied to a two-dimensional multi-channel system which consists of a great number of adjacent entrance and exit channels connected by a filter porous medium.
All existing models aren’t analytical, and need to use complex numerous calculations. The present model is a first an attempt to reduce the problem to a simple analytical scheme based on Berman Similarity and perturbation series solution method that allows it to be used by general engineers not using complex mathematical methods.