(2021). Preface. Mechanics Based Design of Structures and Machines. Ahead of Print.

Abstract To improve the drag reduction performance of underwater vehicles, a skin composed of micro floating raft arrays and a bionic compliant wall is proposed. The micro floating raft is a miniaturization of the floating raft system which is widely used in vibration and noise reduction. The drag reduction characteristics of the skin with various structural parameters are simulated with the IB2d software

Abstract The objective of this study was to overcome the shortcomings of the current analysis and calculation methods of the spatial bar system model, plane beam grillage model and solid element model in the design of the box-girder bridge. For example, the spatial bar system model lacks refined analysis of spatial effects, such as the shear lag effect, effective distribution width problem, and eccentric

Abstract In the present work, the vibration response of the porous functionally graded piezoelectric plates with electro-thermal loading using finite element formulations has been studied. A sigmoid law is used for the material property deviation along the thickness direction. The first-order shear deformation theory (FSDT) with von Karman nonlinear strains and Hamilton's principle is used to obtain

Abstract The present study aims to carry out free vibration analysis of functionally graded single-walled carbon nanotube-reinforced composite (FG-CNTRC) beams under hygro-thermal conditions. The study is carried out using the recently proposed C-0 finite element-based higher-order zigzag theory. The study is carried out on five different CNTRC graded beams. Temperature and moisture-dependent material

Abstract Non-linear vibrations in a cracked orthotropic plate with non-uniform thickness as affected by the fiber orientation have been studied analytically. Linear variation in the plate thickness is assumed in one and two directions. The governing equation of the tapered orthotropic plate is derived using the equilibrium principle. The effect of microstructure is incorporated using the modified couple

Abstract In the current study, layerwise theory (LT) was used to calculate thermal stresses in a clamped rectangular composite plate with nano-silver coating subjected to an external voltage. The composite plate was made of four layers of a piezoelectric or a glass layer, nano-silver coating, and two rectangular silver sub-layers. A set of seventeen differential equations was derived by using the energy

Abstract Two different alternatives over conventional leaf spring are developed in this work, such as composite and hybrid composite-based leaf springs. In composite type, carbon-epoxy based multi-leaf springs are used and the combination of metal and carbon fiber material is used to develop hybrid composite leaf springs. The outputs namely deflection, maximum stress, and fatigue tests are determined

Abstract Topology optimization is a promising technique to define holes and links in the material design space to reduce mass and inertial effect and enhance energy efficiency. In this work, topology optimization of the upper and forearm of SCORBOT ER-4U manipulator is performed considering dynamic loading conditions. The optimized topology corresponding to a loading condition may not be sufficient

Abstract The fracture behavior of a cracked functionally graded piezoelectric plane was investigated under in-plane mechanical and electrical loading. The electro-elastic properties of the plane exponentially varied along the y-axis. Employing the Fourier transform, stress analysis containing a Volterra edge dislocation in a functionally graded piezoelectric plane was carried out. These solutions were

Abstract This comment paper aims to show that the paper contains a serious error. In the commented paper, the displacements are incorrect—two of the shape functions they are based on are erroneous, and they do not properly account for the same degree. The correct forms of all shape functions are explained more deeply here.

Abstract Sandwich panels are widely used in various industries, including the aerospace industry, where they have long been regarded because of their light-weight and high energy absorption capacity. This research introduces a novel type of sandwich panel whose raw material is widely used in the automotive industry. The materials used for manufacturing the sandwich panels addressed in this research

Abstract In this study, viscoelastic damped dynamic behaviors of laminated composite shells (LCS) under different dynamic loads were investigated. In order to obtain better numerical stability, the truncated series method was used in the formation of equations governing the system. While deriving the equations governing the system, the z/R terms are usually neglected, whereas only 3 and higher order

Abstract In this paper, a new structural design method based on MATLAB is developed for the configuration design and optimization of real-life planar manipulators in the high-speed press line. To explore planar manipulators with better performance, the developed method provides a suite of analysis procedures including demonstrating structural synthesis in graph theory, building conversion relations

Abstract A finite element model is proposed for a galloping based piezoelectric energy harvester (GPEH) with an inclined square prism. The absence of any numerical model to capture the effects of inclinations of the bluff body on the performance of GPEH system necessitate the present study. The proposed model is solved in MATLAB environment and validated using the available experimental data. Dynamic

Abstract In the present study, by using a higher-order shear deformation plate theory (HSDT) and considering the second model proposed by Frostig and Thomsen, Dynamic instability, static buckling, and free vibration of the Magneto-Rheological (MR) fluid sandwich plates subjected to an axial periodic force is investigated. MR fluids are a group of smart materials whose rheological properties change

Abstract In this paper, the phenomenon of impact-contact in a closed-loop robotic chain has been dynamically modeled. The motion of this system, which comprises rigid links and ideal joints, has two phases. In the flight phase, the system is suspended in the air and moves only under the effect of Earth’s gravity. And in the impact phase, the mentioned robotic mechanism collides with a rough surface

Abstract When the ground motion is input into a Spring-Viscous damping-Coulomb friction plane isolation system with XY shear keys along a certain inclined angle, XY shear keys will be sheared asynchronously, which will lead to the structural violent curvilinear movement in the plane, resulting in the plane friction coupling effect. In this paper, the influence of the plane friction coupling on the

Abstract Continuum damage mechanics (CDM) studies the deterioration of mechanical properties in materials that leads to material failure. The Lemaitre’s ductile damage model is known as a suitable criterion for damage growth in ductile materials. The standard Lemaitre’s model cannot accurately predict the damage growth in most of bulk metal forming processes with a combination of tension and compression

Abstract Because of the current rapid technological progress, in addition to achieving increased speed and momentum in machine, transmitting more power in a low-noise, lightweight, safe, and economical manner and saving material in gears is crucial. For this purpose, modified bevel gears are common. Therefore, this study investigates bevel gear profile modifications focusing on strength and raw material

Abstract Assessment of dynamic behavior of the gantry cranes by using mathematical modeling and shaking table tests is the subject of this study. In this context, the study was carried out in two stages through theoretical and experimental studies. In the theoretical study, a four degrees-of-freedom nonlinear mathematical model which represents the seismic behavior of gantry cranes was developed. In

Abstract A new curvature, called the squircle, is proposed as a punch profile to provide superior contact performance for bulk elastic materials. Plane contact problems of a rigid squircle-shaped punch pressed onto an elastic half-plane are treated via an integral equation (IE) approach which is evidently substantiated by a finite element (FE) approach. Compared to the piecewise-defines curvatures

Abstract In this study, an equivalent multi-body dynamics model of a rotary compressor for a household air-conditioner is established to predict its vibration responses when eccentric masses on the crankshaft, cyclic gas loads, torque ripple of the motor, connections with rubber washers, and the intake tube and exhaust tube are considered. Practical experiments for measuring the vibration acceleration

Abstract The coupling vibration of a blade-disk-shaft unit is generally studied on the assumption that all the blades are identical. However, the mistuning feature always occurs due to manufacturing tolerances and other reasons in engineering practice. Therefore, a shaft-disk-blades coupling model with the random mistuning feature is derived based on our previous work. Then the statistical analysis

Abstract When a penstock serves a water supply purpose for multiple hydrogenerators in a hydroelectric power plant (HPP), a bifurcation structure should be installed between the main pipe and the branch pipes. This study focuses on a rib-strengthened steel bifurcation structure (RSSBS) with an emphasis on its hydraulic load-bearing mechanism. The finite element method is used with the contact and material

Abstract The complex and changeable environment and the different degrees of toxic hot smoke and unknown danger at fire scenes can seriously affect the fire personnel’s reconnaissance, fighting, and life safety. To address these challenges, in this study, we developed a small wheel-foot hybrid firefighting robot based on an infrared vision fire recognition system. The robot mainly involves a mechanical

Abstract The strong flow field in a hoistway will cause a significant piston effect during the operation of high-speed/ultra-high-speed elevator. Thus, studying the airflow in the hoistway and the reasonable opening of ventilation holes is important. First, a three-dimensional geometric model of the ventilation holes (VHs) and elevator car was established. Based on this model, a multi-region dynamic

Abstract In the present work, the effect of different parameters of friction stir processing (FSP) on microstructure and mechanical properties of pure copper were investigated numerically and experimentally. Three different tool rotation speed (900, 1200 and 1500 rpm) and a constant traverse speed (60 mm/min) were used as FSP parameters. To model the microstructure of stir zone (SZ) which undergos

Abstract This article is presented to investigate the influence of several discontinuity like interfacial-crack, void and inclusion in the bimaterial plate, to analyze the normalized mixed-mode stress intensity factor (NMMSIFs) using XFEM under the uniaxial tensile load with considering the several numerical problems. It is investigated the normalized stress intensity factors (NSIFs) for an isotropic

Abstract In this article, nonlinear free/forced vibrations of a plate undergoing large deflection and moderate rotation have been investigated based on Jacobi elliptic functions. The formulation has been established using a generalized von-Karman’s strain in which nonlinear terms of deflection and rotations are simultaneously included. The governing equations have been derived with the use of extended

Abstract The vibration and damping characteristics of the laminated composite cylindrical sandwich shell with carbon nanotube reinforced magnetorheological elastomer (CNT-MRE) core is presented in this article. Higher order shear deformation theory (HSDT) based on finite element (FE) formulation is employed to derive the governing equations of motion of the laminated composite cylindrical CNT-MRE sandwich

Abstract In the current study, the finite element approach has been used to investigate the effect of compression and tension types of nonlinear edge loads on the vibration and buckling performance of interlaminar hybrid fiber metal laminates (HFMLs) with and without cutouts. The effect of various hybridizations in cross ply, angle ply and quasi isotropic laminate schemes is studied extensively. Toward

Abstract This article deals with the linear and nonlinear buckling behavior of porosity-dependent functionally graded (FG) non-uniform microtubes. The modified couple stress theory is determined to consider small-scale effects on the micro-size tube which is modeled, based on the Euler–Bernoulli beam theory in conjunction with the employment of the conservation energy principle to derive the nonlinear

Abstract An analytical investigation on nonlinear stability of porous functionally graded spherical caps and circular plates under uniform external pressure and elevated temperature, respectively, is presented in this article. Porosities are evenly and unevenly distributed within the structures and the effective properties of functionally graded material (FGM) are determined according to a modified

Abstract In this paper, an improved first order approximate reliability analysis method based on evidence theory is developed to evaluate the uncertain structures reliability. Firstly, the uncertain variables are described by using frame of discernment (FD) and the basic probability assignment (BPA). Secondly, the improved HL-RF (iHL-RF) method and Newton method are used to solve the most possible

Abstract This research presents a new algorithm for the Dynamic Relaxation (DR) method with kinetic damping by utilizing Lagrangian interpolation functions to derive new iterative kinetic DR equations. This procedure leads to an algorithm that, unlike the ubiquitous DR methods, does not require the calculation of nodal velocities, thereby marching forward only through successive nodal displacement

Abstract This paper presents a general and reliable shape optimization scheme for snap-through structures to match a target load-deflection curve. The simulation of the snap-through structures typically requires the Arc Length Control (ALC) method. The adaptive stepping in ALC creates unavoidable discontinuities in the objective function. A discontinuous objective function is often handled by zero-order

Abstract In order to capture the memory-dependent effect and size-dependent effect, present work aims to develop a novel thermo-viscoelastic nonlocal model in micro-scale for the first time to include the simultaneous effects of the fractional order parameter, the viscous damping coefficient, the time-delay factor and the kernel function. Then, the theory is applied to studying the dynamic response

Abstract In this paper, a semi-analytical method is presented for nonlinear vibration analysis of rotating stiffened truncated conical shells with functionally graded materials (FGM) in the thermal environment subjected to harmonic excitation. Considering Coriolis acceleration and the centrifugal force, the governing equations of stiffened rotating FGM truncated conical shells are extracted utilizing

Abstract The nonlinear vibration characteristics of the rotating axially moving circular cylindrical shells in subharmonic regions are investigated in the present paper. The motion equations are carried out based on the Hamilton principle in cylindrical coordinates utilizing Donnell’s nonlinear shell theory. By introducing the suitable airy stress function, three equilibrium equations in the cylindrical

Abstract The cutouts are commonly found in fiber metal laminates to facilitate to pass electrical wires, water/fuel lines and sometime to facilitate easy access and inspection. Sometimes, such cutouts need to be reinforced by providing stiffener around the cutouts to avoid pre-mature failures. This article addresses the effects of reinforced cutouts and non-linearly varying edge loads on the vibration

Abstract This paper is presented to study the free vibration analysis and optimization of CNT/polymer/fiber laminated truncated conical panels. Each layer of the panel is composed of a polymeric matrix reinforced with oriented fibers along with uniformly distributed and randomly oriented agglomerated carbon nanotubes (CNTs). The panel is modeled based on the first-order shear deformation theory (FSDT)

Abstract Determination of sheet metal formability, which is commonly evaluated through a forming limit curve (FLC), is an essential task for part designs in the automotive engineering community. This study provides a coherent comparison among four theoretical FLC criteria including Swift’s instability, Hill’s localized neck, Storen–Rice bifurcation analysis, and Hora’s MMFC. Within these criteria,

Abstract The three-dimensional bending behavior of a viscoelastic functionally graded material (FGM) layer embedded between piezoelectric layers and subjected to an electric field as well as a uniform transverse pressure is studied. An analytical solution is computed for a simply supported viscoelastic smart FGM plate using the state space technique along the thickness direction and a Fourier expansion

Abstract Consideration of standard landing cases from technical guideline document is the traditional design practice followed to ascertain aircraft landing loads. A rationale approach on landing load generation and its impact on flexible airframe dynamic response is explored, considering multi-variate landing conditions for the first time on land-base high performance aircraft. Methodology on nonlinear

Abstract In this study, vibrational behavior of temperature-dependent imperfect functionally graded (IFG) plate lying on an elastic substrate in the thermal environment is investigated. The imperfection effect is considered based upon refined high-order shear deformable plate theory. Thermo-mechanical properties of functionally graded material (FGM) plate are presumed to vary through the thickness

Abstract In this study, dynamic response of functionally graded (FG) nanobeam under a moving load in a thermal environment has been investigated. By considering the size effect, nonlocal Euler–Bernoulli beam theory has been used to model a FG nanobeam. By applying Hamilton’s principle, governing equations of motion and boundary conditions, have been derived. Analytical solution by using Laplace transform

Abstract In this research, control of a passive wire-driven system for the physical support of human beings is discussed. The considered support system does not have any active motor and the required force for steering the system is provided by a human operator. In the cases that the handling point deviates from the desired path, the servo brake units apply force and eliminate the position error. Thus

Abstract In this work, the structural design of a structure-simplified parallel Delta robot is presented, by considering the kinetostatics, kinematic dexterity and workspace. An approach to normalize the dimensionally inhomogeneous Cartesian stiffness matrix is introduced, and a stiffness evaluation index is defined by means of the singular value decomposition of homogenized stiffness matrix, which

Abstract The honeycomb structures, due to minimal density, relative high out-of-plane compression properties, and out-of-plane shear properties, have attracted a lot of attention. Regarding this issue, in the current research, fundamental frequency analysis of the annular plate with two angle-ply multiscale hybrid nanocomposite face sheets and a honeycomb core is investigated. Halpin-Tsai as well as

Abstract The purpose of this study is to investigate the buckling characteristics of a sandwich beam consisting of a porous ceramic core (Alumina), two bottom and upper layers which are gradually changed from ceramic (Alumina) to metal (Aluminum) through the thickness direction. A core with three kinds of porosity patterns is considered. Shear deformation effects are taken into account based on third-order

Abstract This experimental study investigates the behavior of a proposed damper based on austenite Nitinol wires. The damper’s design is so that the wires are always in tension under both tensile and compressive forces. Also, the damper can employ steel wires as a hybrid to enhance the performance of the damper. Steel wires can be employed in parallel with the SMA wires and in the same manner. Therefore

Abstract The aim of this paper is to determine the fatigue damage of structures subject to random vibrations generated by Qualmark chamber. In real life, structures are generally subjected to complex multiaxial random load. To determine their fatigue life, many criteria have been elaborated, mostly in time domain. To minimize the computing time, the fatigue damage analysis should be done in the frequency

Abstract Improving the operating efficiency of piezoelectric tiles is currently a significant subject of scientific study. The current work proposes a viable solution for enhancing the efficiency of existing piezoelectric tiles by incorporating the synergistic effect of various piezoelectric modes of operation with the material grading index. In this article, energy harvesting of the functionally graded

Abstract This paper presents a detailed numerical investigation of behavior of cylindrical tube-shaped textile-reinforced cementitious composites (TRCCs) under monotonic lateral compression loading, and experimental verification. Effects of different thickness and number of layers, different textile materials on behavior of cylindrical tube-shaped TRCCs are investigated numerically. Numerical results

Abstract In scope of this study, forced vibration analysis of viscoelastic helical rods with varying cross-section and functionally graded material are investigated. Differential equations governing the dynamic behavior of helical rods are obtained in Laplace domain by the Timoshenko’s beam theory. Material and section geometry are assumed to be varying functionally along the rod axis. Viscoelasticity

Abstract Many composite structural applications undergo several environmental conditions, so, for the optimal design of the composite structural systems and efficient use of the engineering applications, the accurate vibrational behavior prediction of the composite structures subjected to thermal/hygrothermal environments effect is required. In the current study, vibration response and damping behavior

Abstract The present study includes the free vibration analysis of geometrically imperfect and discontinuous porous functionally graded bi-directional plate (B-FGP) resting on an elastic foundation in a thermal environment. The geometric discontinuity is present in the form of a circular cutout at the center of the plate whereas initial imperfections have been incorporated in terms of geometric as

Abstract Topologically interlocked materials (TIMs) are an emerging class of architectured materials that each of block is supported by their neighboring blocks without any connector, which is inspired by microstructures observed in nature. Therefore, they showed alluring attributes such as resistance to impact, toughness, high flexibility even when using brittle materials, and high crack propagation

Abstract Clearance in ball bearing influences the startup torque and stiffness of bearing and affects the load distribution, load carrying capacity, and life of bearing. The present work is related to deep groove single row ball bearing with their rings groove are in a radial plane and the outer ringway track is made elliptical. During this event clearance along the bearing's circumference, rings are