Traditionally, the main structural system of tall buildings is designed iteratively to resist extreme wind loads, which provides safe, but typically suboptimal building systems. Topology optimization provides a general approach to obtain optimal material layout to carry the required load within specified design constraints. The wind loading on a structure is typically modeled as an equivalent static

The modern power generation system requires steam turbines operating at flexible operating points, and flow instabilities readily occur in the low-pressure (LP) last stage under low-load conditions, which may cause failure of the last stage moving blades. Some studies have shown that within this operating range, a shift of the operating point may lead to flow instabilities. Numerical simulation has

Current trends in the automotive industry towards engine downsizing means turbocharging now plays a vital role in engine performance. The purpose of turbocharging is to increase the engine inlet air density by utilising, the otherwise wasted energy in the exhaust gas. This energy extraction is commonly accomplished through the use of a radial turbine. Although less commonly used, mixed flow turbines

A theoretical model is developed to study the superior sound absorption performance of ultralight mirco-perforated sandwich panels with double-layer hierarchical honeycomb core. Numerical simulations are performed to validate theoretical model predictions and explore physical mechanisms underlying the sound absorption. Systematic parametric study is implemented to investigate the influence of specific

This paper reports on the production and evaluation of a new class of “Z-axis” composite sandwich panel where the core consists of a dense array of vertically-aligned, 3 mm long E-glass fibre composite “beams”. The E-glass fibre bundles were aligned using electrostatic charging. A procedure was developed to retain the orientation of the short-fibre bundles whilst they were impregnated and cured with

This study collects all of the existent papers in the field of acoustic transmission across multilayered plate constructions. Herewith, a comprehensive source is proposed wherein approximately 410 references are reviewed and described from the first 1949 to 2020. In the first part, in addition to the presentation of a complete explanation about the importance of the acoustic analysis of these structures

To study the influence of dynamic flight attitudes on the splash lubrication performance and churning power losses of the intermediate spiral bevel gearbox in a helicopter, a three-dimensional(3D) simulation model consisting of a spiral bevel gear pair, two bearing caps with oil guide holes and the housing is established, and CFD (Computational Fluid Dynamics) simulations with main flight attitudes

Gas metal arc welding (GMAW)-based additive manufacturing (AM) is a key metal 3D printing technology for the fabrication of near-net shape parts. The thermal history of the multi-layer GMAW-based AM process has a significant influence on part quality and substrate deformations, but it is computationally expensive to accurately calculate it based on numerical method or analytical method. Existing data-driven

Due to the increasing popularity of additive manufacturing with continuous fibers thermoplastic composites (TPC), this paper investigates the process of in situ impregnation of dry fiber tow with molten thermoplastic resin as a means to reduce material cost. To better understand impregnation with high-viscosity polymer melts, a 1D version of Darcy’s Law is derived along with Gebart’s equations for

GLARE® is a composite-metal laminate currently used in the Airbus A380 fuselage due to its excellent impact and fatigue performance. GLARE® undergo extensive drilling for riveting purposes making it prone to thermal effects and increased tool wear. Therefore, using coolants becomes necessary, however, conventional coolants can lead to moisture absorption. An alternative is to use cryogenic coolants

This article investigates the ability of using plasma machining for cutting simultaneously two parallel thin layers at different gap distances. The main aim of this work is to identify whether this technology if mechanized can be more appropriate than using a circular saw to process a three-dimensional structure material such as double layers, box sections or rails. This research is aimed at those

Pulsed laser welding was used to join ultra thin Inconel 718 alloy foils whose thickness was 0.2 mm. A fixture was designed to obtain the edge joint. The joint geometry and hot cracking were both observed on the cross sections. The relationship between the height, width of the joint and the energy density were fitted as linear functions. The effect of heat input on the hot cracking in the edge joint

In this letter, we provide experimental evidence of bandgap tunability with global prestrain in additively-manufactured tensegrity-inspired lattice structures. These lattices are extremely lightweight and designed to exhibit a nonlinear compressive response that mimics that of a tensegrity structure. We fabricate them out of a stiff polymer but, owing to their peculiar design, they are compliant and

At present, magnesium alloys are extensively used in numerous applications due to their light weight and better characteristics. Welding of magnesium alloys is regarded as one of the most complex phenomena in various industries. The friction stir welding of magnesium alloys has encouraged abundant scientific and industrial interest as it has the potency to form a good quality joint. Post welding heat

Turn-milling is a hybrid machining process which used benefits of interrupted cutting for proceeding of round bars. However, number of controllable parameters in the hybrid process is numerous that makes optimizing the process complicated. In the present study, an optimization work has been proposed to investigate the trade-off between production rate and cutting force in roughing regime as well surface

In this research effort, an innovative magneto-rheological variable stiffness and damping torsional vibration absorber (MR-VSDTVB) is proposed, and independent variable damping control and independent variable stiffness control are adopted to suppress the torsional vibration of the transmission system. MR-VSDTVB, based on semi-active control principle, exhibits a compact structure and integrates with

A stable square-root approach has been recently proposed for the unscented Kalman filter (UKF) and fifth-degree cubature Kalman filter (5D-CKF) as well as for the mixed-type methods consisting of the extended Kalman filter (EKF) time update and the UKF/5D-CKF measurement update steps. The mixed-type estimators provide a good balance in trading between estimation accuracy and computational demand because

In the present paper, an efficient numerical method for solution of infinite horizon fractional optimal control problems is investigated. The fractional derivative in such problems is considered in the Caputo sense. The methodology developed here, is based on utilizing transformed orthogonal functions to approximate the state and control functions directly. Thereby, the original problem is converted

This paper focuses on the problem of robust fuzzy sliding mode synchronization of uncertain nonlinear systems. A relevant fuzzy sliding mode control(FSMC) law is designed to force the state errors onto the specified surface. The prescribed-time boundedness (PTB) of the dynamical error is guaranteed by introducing the partitioning strategy. The chattering phenomenon, which is inherent to a conventional

As the desire for more flexible aircraft structures increases, so does the need to incorporate the intrinsic nonlinearities in their aeroelastic analyses. In that manner, it becomes essential to fully characterize the aeroelastic behavior and to investigate the effects that common external disturbances, such as atmospheric gust turbulence, might induce. In this work, an augmentation of the semi-empirical

This work aims at presenting, in a comprehensive manner, several approaches to model and simulate closed loop topologies using the classical Lagrangian formulation. One of the great advantages of the Lagrangian approach is its simplicity and easiness of obtaining the equations of motion. However, a critical aspect arises when the mechanical systems include closed loop topologies, since the process

The tuned liquid multiple column damper (TLMCD) is a variation of the tuned liquid column damper (TLCD) that includes multiple vertical columns. A new damping system that embeds TLMCDs within reinforced concrete shear wall systems, termed tuned liquid wall damper (TLWD), is proposed, augmenting the traditional structural component with energy dissipation capabilities. The objective of this study is

This study develops a modified elliptic harmonic balance method (EHBM) and uses it to solve the force and displacement transmissibility of a two-stage geometrically nonlinear vibration isolation system. Geometric damping and stiffness nonlinearities are incorporated in both the upper and lower stages of the isolator. After using the relative displacement of the nonlinear isolator, we can numerically

Dynamic response characteristics and antiseismic performance of the structures which were constructed on the super-deep overburden layer are affected obviously by the seismic motion characteristics of the super-deep overburden layer foundation. In this paper, the seismic motion characteristics of horizontally stratified super-deep overburdenIn this paper, the seismic motion characteristics of horizontally

The development of lightweight, impact-resistant, and high energy-consuming materials is of great significance for improving the defense capabilities of military equipment. As a new type of damping material, metal rubber has demonstrated great potential for application in the field of impact protection. In this paper, the dynamic mechanical response of metal rubber under a high strain rate is studied

The instability of extraction structure under the undercut space in the block caving stope presents specific characteristics: rib spalling and floor heave in ore-loading roadway and collapse of major apexes. In order to study the stress and displacement evolution law of extraction structure under undercut space and reveal the instability mechanism of extraction structure, the numerical simulation model

A novel fault diagnosis method of rolling bearing based on deep metric learning and Yu norm is proposed in this paper, which is called a deep metric learning method based on Yu norm (DMN-Yu). In order to solve the misclassification caused by the traditional deep metric learning based on distance metric function, a similarity criterion based on Yu norm is introduced into the traditional deep metric

Under the condition of close-distance double-thick coal seams’ mining, the serious strata behavior occurred in the lower retracement channel, which is affected by the double disturbance with upper coal-pillar static load and mining dynamic pressure. Field investigation, laboratory test, and numerical simulation were used to study the failure characteristics and stress distribution of N0381 retracement

Abstract In this article, the bending properties of functionally graded material (FGM) sandwich beams are analyzed by using the scaled boundary finite element method (SBFEM) for the first time. The model of FGM sandwhich beams is realized by using high order spectral elements, and only the axial dimension of the beam needs to be discretized. The analytical formula along the thickness direction can

Purpose The purpose of this study is to investigate the effect of aging temperature on the barrel-type solder joint lifetime of electronic devices and to include these effects in the modified prediction model. Design/methodology/approach Several accelerated shear stress tests under different stress amplitudes and aging temperatures were performed. Findings It was found that by aging temperature increasing

This paper proposes an event-triggered adaptive sliding mode control for the steer-by-wire (SbW) system subject to unavailable state, time-varying disturbance, and limited communication resources. Firstly, an adaptive state observer is proposed to estimate the unmeasured state of the SbW system. The uncertain nonlinearity and the time-varying can be estimated by the adaptive fuzzy logic system and

This paper studies a laminar flow over tandem elliptical cylinders at Re = 200. While the aspect ratio (AR) of the upstream cylinder varies from AR = \(a_{1}\)/\(b_{1}\) = 0.25 to 2.00, the aspect ratio of the downstream cylinder is kept constant at AR = 1.00 (e.g., \(a_{2}\)/\(b_{2}\) = 1). This range of AR covers the most important practical cross sections of elliptical cylinders, including normal

A novel method for early looseness state identification of bolted joint beams is proposed in this paper based on generalized variational mode decomposition (GVMD) and a similarity index. In the proposed method vibration signals are decomposed by GVMD, which has the property of the multiscale and fixed-frequency decomposition. To effectively extract the desired modes, the frequency band allocation is

The performances of three types of solar collectors using various nanofluids are theoretically investigated; further, by varying the concentration of binary nanofluids comprising of two highly efficient nanofluids, the performances of the solar collectors are analytically examined. The results obtained demonstrate that MWCNT, CuO, and Fe3O4 nanofluids show a higher efficiency compared with other nanofluids

In the industry, globe valves, which are commonly used to precise control the flow rate along with opening and closing flow in pipes, are technically and economically limited in valve size due to structural instability related to complex internal flow passage. Butterfly valves, on the other hand, have advantages such as low weight and low manufacturing costs, but it is difficult to control the flow

For the firing accuracy problem of the moving tank with different speed and different road level, the modelling and optimization method of the projectile disturbances of the moving tank under the general driving conditions were studied. A high-dimensional multi-objective optimization method for the projectile disturbances of the moving tank considering the different driving conditions was proposed

This paper presents a novel point of view for the performance investigation and optimization of energy absorber devices, which is numerically introduced using the finite element method employing corrugated tubes. The numerical results show that structural or material softening leads to an optimal configuration at which the corrugated or circular tube achieves its peak performance. The performance and

Balancing lateral force is essential to reduce bit vibrations and prolong bit service life. During the process of cutting, the instantaneous cutting situation is governed by the previous blades cutting. This paper introduces a notion called "zoning method" based on the cutting geometry of bit-rock interface, which is dedicated to distinguishing different phases of cutting. Furthermore, a full-phase

The bearing fault signal is a kind of weak signal, so it is easy to be submerged by background noise. As such, signature extraction is facing a great challenge; hence, an effective signature extraction method plays an essential role in bearing fault extraction. In this paper, a new method for bearing fault detection based on an alternative analytic energy operator and sparse Bayesian step-filtering

A general nonlinear complementarity problem (NCP) is formulated as a finite set optimization problem called binary NCP, where design variables are identified by n-bit binary numbers. The binary NCP corresponds to the problem of finding a vertex of an n-dimensional unit cube with zero cost value. Two geometrically intuitive algorithms based on the geometry of the unit cube and another algebraically

A new numerical model combining LaRC failure criterion and extended finite element method (XFEM) is created to describe the failure behavior in fiber-reinforced polymer (FRP) composites. In this model, the onset of intralaminar damages are predicted based on the LaRC failure criterion, and the crack propagation and stiffness degradation are described explicitly by the XFEM. The user subroutine UDMGINI

A study for predicting the creep deformation behavior of a MERT (mixing element radiant tube) type KHR45A steel is carried out. To this end, a modification of the theta projection model is proposed by incorporating a statistical analysis technique especially with a nonlinear mixed-effect model. The model is applied for predicting the creep deformation behavior of a KHR45A steel. Creep curve data used

This paper proposes a method of hip and knee joints coordination control planning based on virtual force. Firstly, the kinematic model of biped robot is established according to the physiological structure of human body. Secondly, the kinematics equation is established based on the jumping motion characteristics of the hip and knee joints, and the motion angles and angular velocities of the hip and

The aims were to characterize MoS2/CoFe2O4 nanocomposite and investigate its thermal therapy efficiency on cancerous (MCF-7) and normal (MCF-10A) human breast cells. Magnetic nanocomposites (MNCs) characterized by scanning/transmission electron microscopy (SEM/TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and vibrating sample magnetometer (VSM) techniques. TEM and SEM

Nonlinear bending analysis was performed of magnetoelectroelastic (MEE) composite plates under a mechanical and magnetoelectric (ME) load by using von Karman’s nonlinear geometric equation and the higher order shear deformation theory (HSDT). Nonlinear higher order partial differential equations for MEE plates were derived by using Hamiltonian equilibrium equation. The MEE plate is considered to have

Sub-10 nm nanostructures have received broad interest for their intriguing nano-optical phenomena, such as extreme field localization and enhancement, quantum tunneling effect, and strong coupling. The range of cutting-edge applications based on single-digit-nanometer scale structures has expanded with the development of nanofabrication technologies. However, challenges still remain in overcoming fabrication

The natural gas (NG) jet characteristics of NG/diesel dual-fuel injection under different NG injection pressures and dual-fuel injection intervals were studied in a constant volume chamber. The schlieren images showed that the development of NG jet was restricted in both axial and radial directions by diesel spray under dual-fuel injection conditions. Consistently, dual-fuel injection reduced NG jet

The paper aims to analyze the InfiniteFocus system for the capability to measure macrogeometry of tooth models manufactured using two material extrusion techniques, i.e. MEM and FFF, and analyze the accuracy of manufacturing the said models. To achieve the goals it was needed to carry out two studies. The first one focused on estimating the measurement error of the microscope in the course of digitalizing

Here, a distinct procedure was adopted to optimize the shape of the NACA 0012 airfoil profile for Reynolds number, Mach number, and angle of attack equal to 2e6, 0.15, and 10.24 deg, respectively. The airfoil shape was appropriately parameterized, and mesh morphing tools were used to bypass the remeshing process. Computational fluid dynamic (CFD) simulations were carried out for all combinations of

The worn status of wheel/rail profiles could change the wheel-rail contact and influence the wear rates of the wheel and rail. Worn wheel profiles of a Chinese intercity train and the worn rail profile of curved tracks were taken into account in this work. According to the dynamics model of the vehicle, teh wheel-rail three-dimensional steady-state rolling contact model, and the Archard wear model

Gas protective walls are safety elements that can withstand the pressure of fires or explosions caused by gas leaks, thus preventing the spread of explosion damage to other facilities or operators. However, in the new construction or expansion of gas facility rooms in existing buildings, the barrier must often be built even if it does not satisfy the legal standards regarding the accepted construction

Failure simulation of 7075-T6 Al alloy is very important due to its relatively low ductility compared to conventional steel. A hybrid numerical-experimental method was developed to determine plastic strains at fracture as a function of triaxiality. The uniaxial tension tests were performed by using the specimens including pure shear, 45° shear, smooth, R5 notch and R15 notch. The fracture locus was

Object detection techniques that achieve state-of-the-art detection accuracy employ convolutional neural networks, implemented to have lower latency in graphics processing units. Some hardware systems, such as mobile robots, operate under constrained hardware situations, but still benefit from object detection capabilities. Multiple network models have been proposed, achieving comparable accuracy with

A significant ongoing issue in realistic humanoid robotics (RHRs) is inaccurate speech to mouth synchronisation. Even the most advanced robotic systems cannot authentically emulate the natural movements of the human jaw, lips and tongue during verbal communication. These visual and functional irregularities have the potential to propagate the Uncanny Valley Effect (UVE) and reduce speech understanding

Metal products are susceptible to factors such as cutting force, clamping force and heat in the machining process, resulting in product quality problems, such as geometric deformation and surface defects. The real-time observation and control of product quality are integral to optimizing machining process. Digital twin technologies can be used to monitor and control the quality of products via multi-scale