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Due to the importance of safety in the process of structural designing of the modern buildings' ceiling, this study gravitates on a novel topic of analyzing thermoelastic response of the concrete ceiling reinforced with nanoparticles of graphene-platelets (GPL). To this end, the mentioned ceiling is considered as a fully-clamped rectangular plate exposed to simultaneous impact of thermal and mechanical loads. The exact form of the elasticity theory in conjunction with the differential quadrature method is employed for acquiring the behavior of the system. Then, an artificial intelligence-based method is used to accelerate the computational process. Efficiency and accuracy of the employed solution are examined and verified by means of a comparative study. The results of this article would be broadly employed in the structural design of the modern constructions in the near future. [ABSTRACT FROM AUTHOR]

In this article, the behavior of the truncated conical shell subjected to thermomechanical loading in their inner and outer layers with internal heat generation source is investigated. The displacement field obeys kinematic of the first order shear deformation theory and the first-order temperature theory is used. Two-dimensional temperature analysis has been performed along the thickness and axis of the shell, which can be defined under various loading and thermomechanical boundary conditions. The set of governing equations is a system of differential equations with variable coefficients which are solved by using the analytical matched asymptotic expansion of the perturbations technique. The mentioned solution has little computational cost, therefore can be used well in parametric studies for optimization. It was shown, axial displacement is somehow independent of the radial axis and its maximum value occurs near the upper boundary. The conical shell has expanded in the radial direction. Also the maximum temperature happens approximately in the middle of the length of the conical shell. The parametric study showed, with the increase heat flux in the outer layer thereby expanding the area of heat application which would let more heat in than out. Also it was found, controlling the lifetime of the structure is the result of directing the cone angle. The results obtained from the analytical solution were compared with the Finite Element Method (FEM) analysis and the results of similar related articles, only to show a good agreement. [ABSTRACT FROM AUTHOR]

This study presents a thermo-mechanical fracture analysis of porous functionally graded cracked plates using the extended finite element method. Three types of functionally graded cracked plates with two different types of porosity distributions, namely homogeneous and nonhomogeneous, are considered in this investigation. Specifically, edge and center-cracked porous functionally graded material plates are analyzed to determine the stress intensity factors. Thermo-mechanical loading conditions are considered to simulate the effects of temperature gradients and mechanical stresses on cracked plates. The analysis aims to investigate the influence of the crack length, crack location, porosity distribution, porosity volume fraction, crack angle, and material gradient on the SIF values. The results of the study provide valuable insights into the behavior of functionally graded cracked plates with different porosity distributions. The findings contribute to the understanding of the mechanical response of such plates under thermo-mechanical loading conditions and can aid in the design and optimization of structures made from functionally graded porous materials. [ABSTRACT FROM AUTHOR]

The mechanical behaviors of the clamped laminated arch with temperature-dependent material properties under the thermal and mechanical loadings are studied in this paper. An analytical method based on the theory of thermoelasticity is proposed for predicting the exact solutions of stresses and displacements in the arch with arbitrary thickness and layer numbers. The clamped support is equivalent to a simply support with a support reaction with the unit pulse function and the Dirac function. The space state method is utilized to establish the state equation by employing the displacements and stresses as the state variables. A slice model is introduced to simplify the coefficient matrix. Based on the continuities at the interfaces, the displacement and stress relationships between the internal and external surfaces of the laminated arch are derived with the transfer matrix method. Exact solutions for the displacements and stresses can be obtained according to the stress boundary conditions on the surfaces of the laminated arch. Finally, convergence and comparison studies demonstrate the excellent efficiency and accuracy of the present method. The influences of material dependency with temperature, thermal load, and thickness-to-radius ratio on the distributions of displacements and stresses are discussed in detail. [ABSTRACT FROM AUTHOR]

The objective of this manuscript is to examine the thermodynamical disturbances in a rotating nonlocal transversely isotropic thermoelastic solid half-space. The enunciation is applied to Lord–Shulman model of generalized thermoelasticity with Eringen's nonlocal elasticity theory. The formulation is subjected to a mechanical load. The expressions for the displacement components, stresses and temperature field are obtained by using normal mode technique and the numerical computations have been carried out with the help of MATLAB software for zinc crystal-like material. The comparisons are made among the results obtained by taking into account the different values of rotation parameter $ (\Omega =0.0, 0.1, 0.3) $ (Ω = 0.0 , 0.1 , 0.3) , nonlocal parameter $ (\varepsilon =0.195\times 10^{-9}, 0.195\times 10^{-4}, $ (ε = 0.195 × 10 − 9 , 0.195 × 10 − 4 , $ 0.195\times 10^{-1}) $ 0.195 × 10 − 1) and time $ (t=0.1, 0.3, 0.5) $ (t = 0.1 , 0.3 , 0.5). The outcomes point out a strong impact of the rotation, nonlocality and time on the physical quantities and agree with the boundary conditions. Although various studies exist in the literature for local and isotropic thermoelastic medium, but the current results are presented in an anisotropic and nonlocal thermoelastic rotating medium, which have not been studied so far. [ABSTRACT FROM AUTHOR]

A thermo-mechanical progressive analysis model is proposed for predicting fatigue-driven delamination in composite laminated plates. The delamination is simulated based on extended layerwise method (XLWM). The traction-separation law is employed to the heat flux transfer and mechanical load transfer across the delamination front. A thermo-mechanical cohesive zone model (TM-CZM) is developed by Peerlings damage law to simulate the fatigue characteristic of delamination front. In the numerical examples, the effects of mesh lengths, acceleration multipliers, interface strengths, and cyclic temperature load magnitudes on the delamination expansion process are investigated, and the temperature-life curves of composite laminates are determined as well. [ABSTRACT FROM AUTHOR]

The aim of the present study is to elucidate the non-linear stability characteristics of randomly distributed carbon nanotube-reinforced fiber composite (RD-CNTRFC) beams subjected to thermo-mechanical loading. Effective material properties of RD-CNTRFC are estimated using the Eshelby-Mori-Tanaka approach and Halpin–Tsai micromechanical techniques. The material properties are considered to be temperature-dependent, and the influence of carbon nanotube (CNT) agglomeration is also incorporated in material properties estimation of hybrid matrix. The strain-displacement relations are assumed by incorporating the higher-order shear deformation theory and geometrical nonlinearity (von Kármán). The governing partial differential equations are obtained by minimizing the total potential energy of the beam. Buckling loads of beam subjected to in-plane compressive loads are estimated using Eigen value approach. Similarly, buckling temperatures are also determined by solving Eigenvalue problem iteratively due to temperature-dependent material properties. The non-linear equilibrium paths under thermal and mechanical loadings are traced through iterative Eigenvalue approach. Numerical results are presented to elucidate the influence of various parameters like CNT agglomeration, ply sequences, span-to-depth ratio, boundary conditions, and mass fraction of CNTs. [ABSTRACT FROM AUTHOR]

In this paper large deformation of the skew microplate made of laminated composite enhanced with graphene nanosheets is investigated using first shear deformation theory (FSDT) when the plate undergoes combination of mechanical and thermal loads. Halpin-Tsai model is utilised to model mechanical properties while for thermal properties Schapery model is considered. First, shear deformation of the plate was obtained while using Green-Lagrange tensor the non-linear strain of the microplate is extracted using the von-Karman assumptions. Then, by Modified Coupled Stress Theory (MCSD), the components of Cauchy and Couple stress tensors are specified. Finally, using Hamilton Principle the governing equation of the microplate and boundary conditions are computed. After deriving analytical governmental equation results are presented for the simple support boundary condition and the proposed model is validated by previously reported data and it proves to be promising. Primary results showed that with raising skew angle deflection and bending moment decreases which means microplate becomes more rigid in higher skew angles. Higher mechanical loads lead to higher deflections and bending moments. Four different configurations of the layers were analysed from which angle-ply configuration possessed highest deflection and bending while UD configuration revealed the lowest values of deflection and bending moment. [ABSTRACT FROM AUTHOR]

The effect of thermo-mechanical load coupling and porosity distributions on vibration and buckling characteristics of Functionally Graded Sandwich Plates (FGSPs) with cutouts is investigated by Finite Element (FE) formulation. Two sandwich configurations are considered and physical neutral surface is incorporated due to material asymmetry. Novel dynamic approach is proposed to evaluate buckling loads. Results obtained are compared with experimental, numerical solutions in literature and revealed that the FGSP buckling capacity under thermomechanical loads improves on using ceramic with lower thermal expansion coefficient. Also, at higher temperature rises, buckling capacity increases due to increasing porosity content, whereas capacity reduces at lower temperature rises. [ABSTRACT FROM AUTHOR]

This paper develops a mathematical framework that aims to control the temperature and rotational speed in the activation process of a gas turbine in an optimal way. These controls influence the deformation and the stress in the component due to centripetal loads and transient thermal stress. An optimal control problem is formulated as the minimization of maximal von Mises stress over a given time and over the whole component. To find a solution for this, we need to solve the linear thermoelasticity and the heat equations using the finite element method. The results for the optimal control as functions of the rotation speed and external gas temperature over time are computed by sequential quadratic programming, where gradients are computed using finite differences. The overall outcome reveals a significant reduction of approximately 10%, from 830 N/mm² to 750 N/mm², in von Mises stress by controlling two parameters, along with the temporal separation of physical control phenomena. [ABSTRACT FROM AUTHOR]

This work focuses on the bending examination of three-dimensional (3D) functionally graded carbon nanotube (CNT) reinforced composite (FG-CNTRC) cylindrical shell exposed to internal pressure. The composite cylindrical shell is assumed to be reinforced in the longitudinal axis. Mechanical properties of the constituents are applied based on the modified rule of the mixture. Distribution of CNTs across the shell thickness is assumed to be uniform and three types of functionally gradients. The governing equations are developed using the Principle of Virtual Displacements (PVDs) based on Carrera's Unified Formulation (CUF) and then differential quadrature method (DQM) is used to solve the governing equations for different combinations of simply supported and clamped boundary conditions. The comparison studies between the obtained results and those available in the literature demonstrate the accuracy and computational efficiency of the present formulation and method. The roles of different factors including the volume fraction of CNTs ( V CN * ), boundary conditions, distributions of CNTs, length-to-radius ratios ( L / r), and mechanical loads, are investigated in the outcomes. The results illustrate that the non-dimensional maximum deflections of functionally graded (FD) distributions are higher than the uniform distributions for different boundary conditions. [ABSTRACT FROM AUTHOR]

Wood branches subjected to bending develop reaction wood to accommodate both tensile and compressive stresses. For softwood, such as Norway spruce and Scots pine, compression wood (CW) develops in the lower parts, while opposite wood (OW) develops on the upper parts of the branch. It is likely that the ratio of CW to OW is optimised for mechanical load bearing by nature. This hypothesis was tested with an analytical beam model using experimental data of stiffness and strength of CW and OW at CW fractions from 0 to 100%. It was found that there is indeed a maximum bending moment capacity around 35% CW, like literature values of CW content in softwood branches. For all compositions, compressive or tensile strength of OW was governing the behaviour. [ABSTRACT FROM AUTHOR]

AbstractPresent work put forwards a numerical approach to quantify the effects of honed-edge and chamfered-edge tools on residual stresses and end-burr generation while performing semi-to-finish cut machining operations. Maximum stresses and temperatures experienced by tools are computed to predict tool wear intensity at its various sections. Furthermore, the impact of tool edge geometry on fracture and the size of the material damage zone ahead of the tool tip has also been detailed. Chip formation, its evolution and separation have been realized using a coupled damage-fracture energy model considering coupled temperature-displacement simulations in two steps modeling strategy: cutting step and stress relaxation and cooling step. A numerical model has been validated with previous experimental results of chip morphology and cutting forces when machining was performed under similar cutting conditions and tool geometrical profile. [ABSTRACT FROM AUTHOR]

Based on the consistent couple stress theory (CCST), we develop a size-dependent Hermitian C2 finite layer method (FLM) for carrying out the three-dimensional (3D) static bending analysis of a simply-supported, functionally graded (FG) piezoelectric microplate which is placed under closed-circuit surface conditions. The microplate of interest is assumed to be resting on a Winkler-Pasternak foundation and subjected to either sinusoidal or uniformly distributed electro-mechanical loads. By setting the material length scale parameter at zero and ignoring the piezoelectric and flexoelectric effects, we reduce the formulation of the Hermitian C2 FLM for analyzing FG piezoelectric microplates to that for analyzing FG piezoelectric macroplates and FG elastic microplates, respectively. The accuracy and the convergence rate of the Hermitian C2 FLM are assessed by comparing the solutions it produces with the exact and approximate 3D solutions of FG piezoelectric macroplates and FG elastic microplates reported in the literature. Because the Hermitian C2 FLM requires that the first-order and second-order derivatives of the primary variables must be continuous at each nodal plane, which in turn leads to their solutions converging rapidly and being able to obtain the accurate results of the electric and elastic variables induced in the microplates, especially for the transverse shear and normal stresses and the electric displacements. The effects of piezoelectricity, flexoelectricity, and the material length scale parameter on the deformations and stresses induced in the FG piezoelectric microplates are significant. A CCST-based Hermitian C2 finite layer method (FLM) is developed for analyzing functionally graded (FG) piezoelectric microplates. The current FLM can be reduced to that for analyzing FG elastic microplates by ignoring the piezoelectric and flexoelectric effects. The current FLM can be reduced to that for analyzing FG piezoelectric macroplates by setting the material length scale parameter at zero. Implementing the current FLM reveals that its solutions converge rapidly and are in excellent agreement with those obtained using the exact 3D models. The effects of piezoelectricity, flexoelectricity, and the material length scale parameter on the static bending behavior of FG piezoelectric microplates are significant. [ABSTRACT FROM AUTHOR]

Functionally graded (FG) materials have shown excellent thermoelastic and creep performance, being considered as excellent materials for cylindrical shells subjected to thermo-mechanical loads. This review provides a detailed account of thermoelastic and creep properties of FG cylindrical shells. A review of governing equations on properties of FG materials as well as thermoelastic response of materials is provided. In depth analysis of the works carried out on the thermoelastic and creep performance of FG cylindrical under different thermal and mechanical loads (such as internal/external pressure, axial loading, etc.) is then conducted. Results obtained so far indicate the superior creep performance of FG cylindrical shells. Although many studies have been carried on thermoelastic response of FG cylindrical shells, their creep properties under different loading is yet to be extended and is a subject of interest for the future researches. [ABSTRACT FROM AUTHOR]

In the present exploration, the unconventional tensors of nonlocal stress and couple stress are incorporated simultaneously in the in-plane nonlinear stability analysis of functionally graded (FG) multilayer shallow micro/nano-arches under thermomechanical loading conditions. For this purpose, the nonlocal couple stress (NCS) mechanics of continuum is implemented into the third-order shear flexible arch theory incorporating the von Karman kinematical nonlinearity. The nanocomposite material of FG multilayer shallow micro/nano-arches is reinforced with graphene nanofillers in accordance with different patterns of FG lamination. The generalized differential quadrature numerical strategy in conjunction with the pseudo arc-length continuation procedure are employed to deduce the roles of unconventional nonlocal and couple stress tensors in the NCS-based nonlinear stability paths of thermomechanical loaded FG multilayer shallow micro/nano-arches. It is found that for all patterns of the lamination, the contributions associated with the nonlocality and couple stress small scale effects on the value of the upper limit as well as the first bifurcation compressive loads are less than those on the lower limit and the second bifurcation ones. Also, it is demonstrated that by combining a temperature rise with the applied compressive lateral load, the upper limit lateral load increases, while the lower limit one decreases. Furthermore, it is seen that by applying a temperature rise, an initial lateral deflection is induced in the shallow micro/nano-arch before applying the compressive lateral load. [ABSTRACT FROM AUTHOR]

The titanium alloys are widely used in aeronautical engineering and medical device materials due to exceptional mechanical properties such as tensile resistance and toughness of fractures. High thermo-mechanical loads occur in metal cutting of Titanium alloy Ti6Al4V, which can decrease life of cutting tool and increase cost of part production. In this paper, the coolant effects on the cutting temperature, surface roughness and tool wear are investigated by using the developed virtual machining system. The cutting forces during turning operations of Ti6Al4V alloy are accurately calculated in order to be used in calculation of cutting temperature and tool wear. The modified Johnson–Cook methodology is utilized to obtain the cutting temperatures along machining paths. Then, the Coupled Eulerian-Lagrangian (CEL) approach is investigated to predict and evaluate the effects of coolants on the cutting temperature in turning operations of Ti6Al4V alloy. The finite element approach is employed to predict tool wear by using the Takeyama–Murata analytical model and modifying the cutting tool geometry during the chip production process. To verify the developed methodology in the study, the results of experiments for the measured cutting temperatures, surface quality and wear rate are compared to the results of virtual machining system obtained by the finite element simulation. Thus, utilizing the proposed virtual machining system in the study, cutting temperatures, surface quality and tool wear during the turning operations of Ti6Al4V alloys with and without coolant can be accurately predicted to enhance the accuracy as well as productivity in the CNC machining operations. [ABSTRACT FROM AUTHOR]

This paper discusses the fracture analysis of FG structures reinforced by CNT exposed to thermo-mechanical load by means of the XIGA framework. The equivalent properties of functionally graded structures reinforced by CNT (SWCNT & MWCNT) are computed using micro-mechanics models. The volume fraction of CNT has an impact on the mechanical and thermal properties. Then, a preexisting crack is considered in the CNT reinforced FG square structure to perform the fracture analysis. The SIFs are calculated by the interaction integral method. It is noted that delaying of the fracture is possible with the increase of CNT content in FG structure. [ABSTRACT FROM AUTHOR]

The elastic mechanical behaviour of materials is very important to the design and service safety evaluation of mechanical load components. In order to accurately measure the elastic mechanical behaviour of metal structures with a non-destructive testing way, a dual-mode bulk-wave electromagnetic acoustic transducer (EMAT) is developed for both ultrasonic longitudinal wave and shear wave measurement. The elastic modulus and Poisson's ratio of metals are directly obtained with the velocities of the longitudinal and shear waves. In order to improve the efficiency of electromagnetic acoustic transducer, the electromagnetic acoustic parameters were characterised and optimised by numerical simulation. The results show that the developed dual-mode EMAT can successfully excite and receive longitudinal and shear waves, and the elastic modulus and Poisson's ratio of different materials (copper, aluminium and steel) obtained through experiments using the developed dual-mode EMAT are very close to the reference values. [ABSTRACT FROM AUTHOR]

The adaptation of traditional roads (tRoads) into electrified roads (eRoads) generally requires the inclusion of a charging unit (CU) in the pavement. In this study, the structural behaviour of a conductive eRoad is assessed using 2-D FEM simulations, and compared to the behaviour of a tRoad. Thermal and mechanical loadings representative of field configurations were applied and the relaxation response of the bituminous mixtures was calculated. Resulted strain and stress fields indicated a differential thermomechanical behaviour of the eRoad components. Strain and stress concentrations due to daily temperature fluctuations were pronounced near the interface with the CU. Traditional parameters obtained at the bottom of the bituminous layer were found similar for tRoad and eRoad. It is concluded that the development of new failure criteria is necessary to predict the service life of eRoads, in order to consider the thermally-induced strain and the impact of the volumetric rearrangement of the CU. [ABSTRACT FROM AUTHOR]

The application of liquid nitrogen is being considered nowadays because it is clean and environmentally friendly and improves product quality. The cryogenic cooling can also be useful in hard machining process where workpiece is exposed to high thermo-mechanical loads. Thermal loads are one of the factors affecting residual stresses and microstructural changes in a material. There is no study in literature to evaluate the effect of cryogenic cooling for evaluation of thermo-mechanical loads during the machining of the hardened AISI H13 steel. Therefore, in the present study, to control and investigate the thermal loads, microhardness, white layer thickness, and surface quality in hard machining of AISI H13 steel, the cryogenic cooling system was employed during the process. Results indicated that depth of cut was the most influential item on temperature enhancement of cutting zone, while high feed rates were responsible for enhancement of microhardness surface roughness. Intense and rapid cooling using the liquid nitrogen spraying was found effective strategy to reduce white layer thickness and improve surface quality at the machined surface. [ABSTRACT FROM AUTHOR]

This study included two aspects - an experimental study and a numerical study – to determine which type of composite materials is more efficient in repairing corroded and cracked aluminum plates that have been repaired by the composite material technique. In the numerical study, the adhesive damage area theory was used to analyze the effect of corrosion and inclined crack behavior of Al 2017 A aluminum plate under thermo-mechanical loading. The effects of crack inclination and temperature change were highlighted as well as the effects of patch shape and type. In the experimental study, we prepared corroded sheets, repaired them with several types of composite materials, and then subjected them to tensile strength until wear. The results obtained either through a numerical or experimental study, proved that the boron/epoxy type composite is the most efficient in rust repair compared to the other types used in this study. [ABSTRACT FROM AUTHOR]

This article considers a bidirectional functionally graded (BDFG) beam with various distributions of volume fraction. The impact of these distributions on the buckling and bending response of BDFG beam with general boundary conditions is investigated via a quasi-3D solution. It is assumed that the beam is exposed to a set of in-plane varying compressive loads and there mechanical characteristics change in both directions. Also, the BDFG beam is considered to be exposed different external mechanical loads. Hamilton's principle is employed to derive the governing equations, which are then solved using analytical solution to obtain buckling and bending characteristics. The precision of the current formulation is investigated via a comparison with available data in literature. Some numerical results are presented and discussed to assess the effect of different parameters such type of volume fraction, boundary condition, varying load, and beam geometry on the buckling and bending of BDFG beam. [ABSTRACT FROM AUTHOR]

Current research is dedicated to study the influence of angular velocity and gravity field on the thermomechanical interactions in a non-homogeneous, nonlocal, micropolar elastic half-space whose surface is subjected to a mechanical load. The formulation is established in the context of dual-phase-lag model of generalized thermoelasticity. The material is supposed to have non-homogeneous thermoelastic properties in the x-direction. Exact solution of the problem is procured by applying normal mode technique. Numerical computations for nonlocal stresses, displacement components and temperature field are performed for a suitable material and are depicted graphically. Certain special cases of interest have been derived from the current report. [ABSTRACT FROM AUTHOR]

Due to improvements in diesel engine power and performance, the piston in the combustion chamber is subjected increasingly higher thermal and mechanical loads. The cyclic changes in thermal and mechanical stresses seriously affect the piston fatigue life. Therefore, it is necessary to analyze the strength of the piston in the design process. In this paper, the finite element analysis of piston under thermal, mechanical and thermo-mechanical loads coupling is carried out by using the ANSYS software. By analyzing the heat and force distributions on the piston, the stress and strain distributions on the piston can be obtained, so as to determine the maximum stress concentration areas and check whether the piston strength meets the requirements. Results indicate that the highest temperature on the piston appears at the top of the combustion chamber bulge, where the deformations of the piston and combustion chamber are the most serious. There is a large stress concentration in the contact between the piston pin seat, the piston pin hole and the piston. The minimum number of piston cycles is 1.2×106 times, which meets the piston cycle number from starting, running, and to stopping process. Thus the strength of the diesel engine piston meets the requirements. [ABSTRACT FROM AUTHOR]

The current study explores two-dimensional disturbances in a nonlocal photothermoelastic semiconducting medium with two temperatures by implementing the Green Naghdi-II theory. The thermal conductivity of the medium is assumed to be varying with temperature changes. The formulation is subjected to an inclined mechanical load. A lot of research has been carried out in recent years on photothermoelastic medium, but not much attention has been given to study the dynamical interactions in a nonlocal photothermoelastic medium with two temperatures and variable thermal conductivity under the effect of inclined mechanical load. The analytical solutions of physical field variables such as temperatures, stresses, carrier density and displacement are obtained by using the normal mode analysis method. For a specific material, numerical computations are performed to illustrate the results. The results that were obtained through numerical analysis for the physical quantities are displayed graphically. The comparisons are made among the results obtained by taking into account the different values of time, inclination angle, two temperature parameter, nonlocal parameter, variable thermal conductivity and photothermal elastic constants. Some special cases of interest have been inferred from the present study for validation. [ABSTRACT FROM AUTHOR]

Fragility and the presence of a poisonous substance (lead) are the two major issues with traditional piezoceramics and structures that include them. This work suggests an active structure that is lightweight, flexible, and eco-friendly such that a polymeric foam plate is sandwiched between two piezoelectrically activated nanocomposite layers. A combination of a polymer and piezoelectric nanowires (NWs) of zinc oxide (ZnO) is used in the nanocomposite layers. For the proposed active structure, two types of void distributions and functionally graded (FG) distributions of the NWs have been assumed in each corresponding layer. The buckling characterization of the proposed eco-friendly active sandwich plate (EFASP) under biaxial mechanical loads has been conducted using an extended meshless solution based on a third-order theory. An in-depth parametric study on the EFASPs' biaxial buckling resistance revealed that increasing NW content considerably enhances buckling resistance, with this enhancement strongly reliant on the distribution profile of the NWs. Moreover, it was observed that embedding voids in the substrate layer can lead to a large structural weight reduction while only marginally lowering the buckling performance of suggested EFASPs. [ABSTRACT FROM AUTHOR]

Fan vaulting is a magnificent innovation of English Gothic architecture that has been admired since the 14th century. However, how this breathtaking structural form works under mechanical loads (like self-weight and support displacement) is still poorly understood. One of the many interesting open issues is the mechanical role of backfill. This paper studies how the existence and the height of the backfill affect the horizontal and vertical reactions expressed on the fan vault by the tas-de-charge and the lateral longitudinal wall. In order to analyse this, discrete element models are prepared for small-span and large-span fan vaults constructed of jointed masonry, with Voronoi-shaped elements forming the backfill, and then the structures are submitted to self-weight and gradually increasing quasi-static outwards support displacements. The ratio of horizontal versus vertical reactions is applied to quantify how stable these vaults are in the case of different levels of backfill. The effect of shell thickness is also addressed. [ABSTRACT FROM AUTHOR]

In this study, mixed-mode stress intensity factor (MMSIF) and crack growth analysis in functionally graded materials (FGMs) with discontinuities (crack, inclusion and void) are presented. The extended finite element method (XFEM) based study with the partition of unity method is utilized under thermo-mechanical loadings. The effect of mechanical and thermal loadings acting individually and combined on cracked FGM plate with other discontinuities is carried out. In mechanical loading, uniform tensile, shear, combination (tensile and shear), point, uniformly varying, and exponential loading are considered, whereas in thermal loadings, isothermal and adiabatic loadings are utilized. The objective of this present study is to find the MMSIF and crack growth analysis of FGM plate with discontinuities under different thermo-mechanical loadings, where the interaction study of discontinuities and different thermo-mechanical loadings are investigated. The present problem is modeled in MATLAB (R 2015a) environment and the results of the present model are compared with the results from the literature. [ABSTRACT FROM AUTHOR]

Thermo-mechanical buckling analysis of laminated spherical shells bounded with the piezoelectric actuator layers has been presented in this article. Applied loads are a combination of thermal, mechanical and electrical loads. Derivations of equilibrium and stability equations are based on the classical laminated shell theory and Sanders's nonlinear kinematic relations. The analysis employs the Galerkin method to achieve closed-form formulas for the buckling loads of the piezo-laminated spherical shell. Effects of applied actuator voltage, voltage sign, geometrical parameters of the shell (length, diameter, and thickness), material properties, and layout of composite layers on the buckling strength are investigated. Analytical solutions are obtained for three types of thermal loading, and one thermo-mechanical loading condition. The results are validated by the known data in the literature. [ABSTRACT FROM AUTHOR]

In this paper, the mechanics of shear deformable micro beams is investigated via finite element analysis, and a machine learning technique (Deep Learning Neural Network (DLNN)). DLNN is provided for the first time to accurately model and predict this behavior. Using the Finite Element Method (FEM), the obtained coupled equations of motion for shear deformable micro-scale beams are solved using a combination of Timoshenko beam theory and the modified couple stress theory (MCST). The results are compared with literature for each analysis to show the accuracy and the proposed finite element model. After presenting the mechanical model, by using Finite Element Analysis (FEA), a deep learning neural network model is developed for small-scale structures and the capability of this model in predicting different mechanical behavior under thermo-mechanical loading is investigated. It is shown that the presented model has great accuracy in predicting both static and dynamic behavior of small-scale structures with a significant reduction in the computational cost. The application of DLNN for modeling the machines of small- scale structures is a step forward for predicting the behavior of Nano/Micro Electro Mechanical Systems (NEMS/MEMS). [ABSTRACT FROM AUTHOR]

The thermo-electro-mechanical coupling (TEMC) problem of the piezoelectric structure was analyzed. And the stabilized node-based smoothed radial point interpolation method (SNS-RPIM) was utilized during the computation. And the fundamental formulas were derived under thermo-mechanical load and the model of the problem was analyzed with triangular elements. The existence of thermal stress was taken into consideration. The dynamic behaviors for the TEMC problem were investigated by SNS-RPIM and finite element method (FEM) when different kinds of thermo-mechanical loadings were applied. The superiority of the proposed scheme for the TEMC problems was verified. The empirical constant was set to negative. Besides, the temperature rise can make the model softer and thermal load increase, which leads to a decrease of structural stiffness and natural frequency, thus, the displacement increases. [ABSTRACT FROM AUTHOR]

An innovative application of the fiber reinforced engineered cementitious composite (ECC) in thermal insulation wall is presented in this paper. Special focuses are paid for the purpose of eliminating bond failure between the structural layer, thermal insulation layer and surface protective layer, and enhancing cracking resistance of the surface protective layer. ECC with characteristics of low drying shrinkage (LSECC), strain-hardening and multiple cracking was used as surface protective material in the wall. The test results show that uniformly distributed steel wires crossing the thermal insulation layer at an inclination angle to the direction of horizontal direction of the wall and embedded in the structural concrete layer with certain length can provide sufficient bond strength of structural layer, thermal insulation layer and surface protective layer. Tensile test results on LSECC used in the surface protective layer of the wall show that LSECC can provide sufficient tensile strain capacity to adsorb the deformation induced by temperature change, material shrinkage and mechanical loads. Meanwhile, high crack opening control ability and fine crack opening is expected as well during service. [ABSTRACT FROM AUTHOR]

The high temperature environment makes the buckling of composite laminated plate happen earlier. Further weight savings can be achieved once the plate has a favorable postbuckling stiffness. This study aims to address this issue by developing a ROM-driven lamination optimization to maximize the buckling and postbuckling performance of compressed plates under initial temperature field. The reduced-order model(ROM) constructed using the improved Koiter theory is reformulated to be suitable for thermal-mechanical buckling problems. A linear subspace of the force space is represented to be the span of the mechanical load, the thermal load and a set of predefined perturbation loads. The thermal load related to the initial temperature field is constant during the increase of in-plane compressive load. An independently additional degree of freedom corresponding to the thermal load is implemented into the construction of the reduced-order model. The buckling and postbuckling performance can be extracted from the solution of reduced-order model, and then subsequently selected as inputs to achieve the optimal laminate. The main novelty of this work is to achieve the thermal-mechanical buckling and postbuckling optimization, benefitting from the highly efficient single run of thermoelastic geometrically nonlinear analysis. Various numerical examples have been selected to validate the performance of the proposed method, considering the influences of length-to-width ratio, α1/α2, ply number and nonuniform temperature field. [ABSTRACT FROM AUTHOR]

The offshore industry faces continuous challenges as new applications (such as floating wind turbines, wave energy converters, etc.) are being proposed and old applications (such as offshore oil and gas floating units) are being installed in deeper waters. Mooring systems are among those that have faced the greatest evolution, mostly due to the recent successful use of synthetic fibre ropes. The complex mechanical loads to which these systems are subjected during service, in combination with their inherent nonlinear mechanical behaviour, call for the use of numerical techniques for the prediction of their stress and strain response. Although there can be found a considerable amount of proposed models in the specialised literature, it is noted that the great majority of them is developed to be used with very specific materials, or to model few specific phenomenon, such as creep, relaxation, or monotonic load, for instance. With that in mind, the major contribution of the present paper is that it proposes a constitutive framework that accurately predicts the stress-strain response under cyclic load of four of the most used fibres in synthetic mooring ropes, namely, polyester, high modulus polyethylene, polyamide and aramid. A polyester subrope was also modelled, which shows the robustness of the proposed methodology. [ABSTRACT FROM AUTHOR]

Due to importance of exploring novel ways to protect systems from detrimental influences of thermal shock phenomenon, this study aims at analyzing the transient coupled poro/thermoelasticity response of functionally graded CNT reinforced (FG-CNTR) nanocomposite panels surrounded by non-polynomial kind of elastic foundation. In addition to thermal shock, the mentioned nanocomposite structure is subjected to initial mechanical loads in different orientations. As the accuracy of the results is of high prominence to guarantee reliability of the practical designs, the governing equations are developed on the basis of the exact type of elasticity theory known as three-dimensional form. Also, analytical solution is determined by applying Navier approach to solve the governing differential equations for simply-supported boundaries. Energy balance equation is utilized to determine the temperature gradient of the cylindrical panel considering the assumptions that the internal surface is fully isolated and the external one is subjected to thermal shock loading. Modified type of Dunber and Abate's approach is implemented to inverse the Laplace transform in order to map the response of the system from Laplace into time domain. Convergence of the determined deflection, shear stresses, and temperature versus passing time is analyzed and confirmed. The acquired numerical results elucidate the role of different factors such as mid-radius to thickness ratio, volume-fraction, and scattering pattern of CNT in the transient coupled poro/thermoelasticity response of the FG-CNTR nanocomposite cylindrical panel. As a valuable result, it is found that increasing the volume-fraction of CNT applies negative impacts on the variation of the transverse shear stress. [ABSTRACT FROM AUTHOR]

Leaflet damage has been documented to occur while deploying a transcatheter aortic valve (TAV) due to mechanical loads during the crimping procedures. In this study, the impact of compressive stress on folded leaflets was measured to investigate the mechanism of traumatic leaflet tissue damage. Numerical simulation of TAV crimping procedure was adapted to calculate stress magnitude and distribution of leaflets. A 20 mm balloon expanding short stent TAV with 0.25 mm thickness leaflets was used in the simulation. Then the calculated stresses were applied on leaflet material (bovine pericardium) samples by loading experiments. Mechanical properties evaluation combined with histological and microscopy observation were used to investigate the tissue damage. The elastic modulus and the tensile strength of the tissue began to decrease significantly at 2 MPa stress and 2.5 MPa stress, respectively. No significant differences were observed at 0–1.5 MPa stress. When the TAV was crimped to 14 Fr and 12 Fr, the 2 MPa greater areas on leaflets increased from 18.17% to 76.96%. 2 MPa compressive stress might be the threshold value for leaflet damage. The TAV crimping size should be paid attention to avoid the compressive stress higher than 2 MPa. [ABSTRACT FROM AUTHOR]

During service, residual stresses are generated as a result of plastic deformation induced by mechanical loads, thermal loads, or variations in the applied welding. Despite extensive research on welding processes, there remains a significant gap in understanding the combined effects of different welding parameters on the residual stresses and hardness of welded 316 stainless steel pipes. This study addresses this gap by systematically examining parameters of welding currents (90, 100, 110, 120, 140, and 160A), metal wire types (6010, 6013, and 7018), and wire diameters (3.2 and 2.25 mm), to provide a comprehensive analysis of their impact on mechanical properties. As part of the experimental work, arc welding, hardness tests, and X-ray diffraction tests were conducted. In different welding conditions, residual stresses increase as the hardness decreases, according to theoretical calculations based on X-ray diffraction analysis. It is observed that as residual stresses increase, hardness levels decrease, providing valuable insight into the relationship between these factors. In this systematic investigation, existing knowledge is extended. [ABSTRACT FROM AUTHOR]

The aim of this paper is to study the T-stress and its effect on crack propagation in FGM materials with adiabatic cracks subjected to thermo-mechanical loading based on the J-integral formulation and the extended finite element method (XFEM). Path-independent J-integral responses of T-stress for adiabatic cracks and the effects of incompatible terms for FGMs are discussed. Having examined the T-stress parameter, the effect of fracture characteristic/process length on crack propagation angle in adiabatic cracks is studied. The results show that the initial crack propagation angle deviates from the standard propagation angle by increasing the size of the fracture process zone. [ABSTRACT FROM AUTHOR]

The displacement and temperature discontinuity method is extended to the coating structure of a two-dimensional decagonal quasicrystal–crystal system, where the behavior of interfacial cracks is studied under a thermo-mechanical load. The fundamental solution of unit-point displacement and temperature discontinuity is derived on a crack surface. Based on superposition principle and finite part integrals, the boundary integral–differential equation is obtained. The algebraic equations for solving displacement and temperature discontinuities on line elements are constructed for numerical simulation. Stress intensity factors and energy release rate at crack tips are represented by the discontinuities. Influences of many factors on fracture are discussed. [ABSTRACT FROM AUTHOR]

In this article, geometric and material nonlinear analyses of planar and space trusses subjected to thermo-mechanical loads are performed using the Total Lagrangian formulation. The material properties are Thermally InDependent (TID). By obtaining the equilibrium path of these structures, their buckling and post-buckling behaviors are predicted under thermal and mechanical loads. To consider material nonlinearity, a mixed isotropic–kinematic hardening criterion is developed in this formulation. The behavior of material is assumed to be bilinear. To solve nonlinear equations iteratively, the Generalized Displacement Control Method (GDCM) is used. The authors' scheme is general and can be employed for different types of planar and spatial truss structures having complicated geometries and behaviors. Several popular benchmarks are considered to show the accuracy and correctness of the proposed formulation. Corresponding equilibrium paths and stress–strain curves are reported for each problem. [ABSTRACT FROM AUTHOR]

Up to now, no researches have been yet presented to investigate the static analysis of the carbon nanotube reinforced composite (CNTRC) doubly-curved nanoshells with considering the effect of thickness stretching in thermal environment. In this paper, deflection analysis of the CNTRC doubly-curved nanoshells subjected to thermo-mechanical loading based on nonlocal strain gradient theory is investigated. The temperature variation vary through the thickness linearly. Five different types of distributions of CNTRC including UD, FGX, FGV, FGO and FGA are considered to investigate their effects on the mechanical behavior of the doubly-curved nanoshells. All of the mechanical properties of the nanoshell are considered as temperature dependent. Hamilton's principle is applied to derive the governing equations of motion, where Navier method is used to obtain the deflection of the nanoshells with simply-supported boundary conditions. The obtained results demonstrate that the effect of thickness stretching has vital role on the deflection of the CNTRC doubly-curved nanoshells. [ABSTRACT FROM AUTHOR]

Present investigation deals with the snap-through phenomenon in a thermally pre-buckled or post-buckled reinforced composites beam. Composite laminated beam is reinforced with graphene platelets (GPLs) where the weight fraction of GPLs may vary in each layer. The governing equations of the beam are obtained by means of the first order shear deformation beam theory and the von-Kármán type of kinematic assumptions. The conventional Ritz method with Chebyshev polynomials is used to discretize the governing equations and establish a set of non-linear equations dealing with the response of a beam under the action of thermal and mechanical loads. Furthermore, the case of uniform temperature elevation in the beam and uniform lateral pressure is considered. At first, the response of the beam under uniform temperature elevation is obtained. Depending on the magnitude of temperature rise, beam may remain flat or undergo thermal post-buckling. Using the displacement control strategy, the non-linear eigenvalue problem is solved. After that the response of the pre-buckled or post-buckled beam subjected to uniform lateral pressure in large deflection is evaluated. Due to the possibility of snap-through phenomenon, the cylindrical arch-length technique is employed. At first, two comparison studies are provided to assure the validity and efficiency of the developed formulation. After that, novel numerical results are given to discuss the effects of temperature change, weight fraction of GPLs, distribution pattern of GPLs and boundary conditions. It is shown that the limit loads of the snapping phenomenon and the intensity of the snap-through phenomenon are highly dependent to the mentioned factors. [ABSTRACT FROM AUTHOR]

508III steel is widely used to manufacture the key components of water chamber head of nuclear island evaporator because of its excellent performance. Due to the large milling parameters and their high strength, hardness, and adhesion, cemented carbide tools are subjected to large cyclic mechanical load. Serious tool wear and low service life have become more prominent problems in the cutting process. Therefore, the research on the dynamic cutting force and wear mechanism of cemented carbide tools for milling 508III steel is attracting more and more attention. In this study, based on the theory of cutting mechanics and the force balance condition of circular tool cutting unit, the cutting force model under ideal condition was established. On this basis, the tool dynamic cutting force model considering flank wear was constructed. The tool wear experiment of milling 508III steel was carried out under different cutting parameters, and the change curve of tool wear life and the actual dynamic cutting force at different cutting time were obtained. And the accuracy of the established dynamic cutting force model was verified. Scanning electron microscopy and energy dispersive X-ray spectroscopy were used to analyze the wear morphology and mechanism of cemented carbide tools. The research findings can are of great significance for revealing the tool failure mechanism of milling water chamber head, reasonably selecting machining parameters, and improving the machining quality and efficiency of nuclear power parts. [ABSTRACT FROM AUTHOR]

In this work, a FGM thick wall tube under both thermal and mechanical loadings is studied by referring to the Mori-Tanaka method. The studied FGM tube is assumed to be made of two distinct linear elastically deformable materials equipped with unique volume fractions. Specially, its material parameters are firstly evaluated in the scheme of the Mori-Tanaka method which can more accurately depict the effective material properties of FGMs composites. Later, we derive the ordinary differential equation (ODE) of the displacement along radial direction, based on which we determine the approximate analytical results of displacement and later derive explicit forms of stress components along all the radial, axial and circumferential directions. After comparison, we found that the derived analytical results agree well with that obtained through numerical method. Moreover, for the same researching problem we found the Mori-Tanaka method could outperform the Voigt method. Further, the results are valid for materials with different Poisson's ratios rather than constant Poisson's ratios usually used in the existing references. Finally, parametric studies are also conducted by exploring the variations of the displacement and stress components affected by different volume fractions and distinct thermal conductivities and expansion coefficients. [ABSTRACT FROM AUTHOR]

This article deals with the theoretical investigation of deformations in a rotating isotropic functionally graded double porous thermoelastic material (FGDPTM) with voids by means of two temperature Green-Naghdi III (G-N III) model of generalized thermoelasticity. A gravitating magneto-double-poro-thermoelastic two-dimensional substrate is influenced by both thermal shock and inclined mechanical load at the free surface. The normal mode technique is carried out to derive the expressions for displacements, temperatures, volume fractions, and stresses. Numerical values for copper-like material are utilized to execute several graphical implementations representing the variations in the aforementioned variables in the presence and absence of different parameters. Furthermore, comparative studies among FGDPTM, functionally graded porous thermoelastic material (FGPTM), and functionally graded thermoelastic material (FGTM) structures are displayed graphically with and without two temperatures. [ABSTRACT FROM AUTHOR]

Transient stress and deformation analysis of a functionally graded rotating cylinder made of Al-Sic with short length under thermal and mechanical loads is studied in this paper. It is assumed that the cylinder is located on a friction bed and is subjected to an external torque. The material property is assumed to be variable along the radial direction based on volume fraction distribution. Thermal conductivity equation with time parameter is solved to obtain temperature distribution by Finite Difference Method. First-order shear deformation theory is used to derive kinematic relations. The governing equations are derived using minimum total potential energy and Euler relations. These governing equations are solved using the method of Eigenvalue and Eigenvector. The physical and loading boundary conditions are applied to obtain unknown coefficients. As the main result of this paper, it is concluded that the radial displacement is uniform at the middle of a cylindrical shell and is decreased to zero with an increase of axial coordinate. [ABSTRACT FROM AUTHOR]

This study presents a nonlinear controller with a wind speed estimator for a variable speed wind turbine at below-rated wind speed. A nonlinear controller is designed to address the rapid variations in wind and uncertainties in the wind system. The objective of nonlinear controller is to maximize the energy that can be extracted from wind with a reduction on mechanical loads. The synergetic and terminal synergetic controllers are proposed for improving energy capture and load mitigation. Also, the stability of the controllers is analysed by Lyapunov stability. The proposed controllers were validated using the FAST (Fatigue, aerodynamics, structures and turbulence) numerical model. Finally, a comparative study has been made between the controllers for different wind speed profiles. [ABSTRACT FROM AUTHOR]

This paper presents a finite control set model predictive control (FCS-MPC) approach for two induction machines driven by a nine-switch inverter (NSI). In the traditional approach, two separate voltage source inverters are necessary to drive the independent induction motors. In the proposed method, the nine-switch inverter is used to control the separate motors with a reduced number of switching devices compared to traditional method. A robust control strategy that eliminates the interactions between separate mechanical loads is required to achieve a proper independent speed and torque control for two induction machines through the NSI. To ensure the reliability of the machine operation, the indirect-field oriented control-based model predictive control strategy is proposed. The proposed control strategy is experimentally validated across the 3.2 kW SiC-based NSI prototype. The control algorithm is performed on an Altera Cyclone IV Field-programmable gate array. The experimental results demonstrate that the proposed dual-model predictive control method provides a good and robust motor control operation under different loading conditions. Two induction motors are successfully controlled, and the independent speed and torque control are achieved. [ABSTRACT FROM AUTHOR]

In this work, the results of a detailed art technological investigation of the icon Last Supper from the Russian Memorial Church in Leipzig (Germany) are presented. The icons of the iconostasis of the church were made in the workshop of N.S. Emelyanov in Moscow in 1912. The investigation showed that the painter in principle technologically adhered to the traditional way of making icons. The panel is made of boards of lime wood with two crossbars on the reverse. The paint was applied to a chalk ground over a textile layer. The traditional iconographer's palette was expanded by a few contemporary pigments. The binding agent is classic egg tempera. Originally, the layers of paint had an oil varnish (olifa). The main aim of the project VirtEx, introduced in this paper, is to expand existing methods with numerical material and structural models to be able to predict quantitatively the behaviour of wooden artefacts under loads due to climate changes as well as mechanical loads. The detailed art technological investigation provides the required data for the computer models. The numerical data can then be validated with technologically exact copies and replicas. In the introduction to the article, the current state of research on icon painting techniques is also outlined. [ABSTRACT FROM AUTHOR]