A method is developed for propagation of model parameter uncertainties into frequency response functions based on a modal representation of the equations of motion. Individual local surrogate models of the eigenfrequencies and residue matrix elements for each mode are trained to build a global surrogate model. The computational cost of the global surrogate model is reduced in three steps. First, modes

In order to improve the finishing efficiency of the Magnetic Abrasive Finishing process, we proposed a new MAF process with renewable abrasive particles using compound magnetic finishing fluid circulatory system in this paper. This new finishing process has a circulating system that uses a conveyor belt to renew the mixed abrasive particles. This not only maintains the stability of the finishing but

Food waste caused by processing is serious, brown rice over-milling has caused mass nutrients loss and waste. Brown rice milling process is mainly friction interaction between brown rice-roller. To better understand brown rice shearing friction behavior under working conditions, a developed friction tester combined with observation is used to obtain in-depth working principles under working conditions

This work presents the investigation results of a journal bearing lubricated with magnetorheological fluid that is activated by a local constant magnetic field to vary both the local flow resistance and pressure. The bearing performance is assessed via Finite Element Modelling (FEM) and results are corroborated by experiments. The FEM model uses the Bingham model to describe the fluid film. A dedicated

This paper proposed an acoustic model of ultrasonic transmission with the dry tribological interface considering the geometric dispersion effect and the boundary effect. Poisson's ratio is introduced into the Hamiltonian expression, which establishes the energy propagation characteristics of tribological interface. Based on microwave theory, the boundary effect of ultrasonic propagation is analyzed

Hastelloy-X is a nickel-based superalloy predominantly using in engine combustion zone parts of gas turbines. Micro-holes are drilling to the surface of these parts for air-cooling passageways to improve part-life by reducing thermal fatigue. Laser, micro-electric discharge machining (µEDM), and micro electrochemical machining (µECM) are the major processes for creating holes in superalloys. Yet, if

Engineering ceramic has been widely used in various fields, especially in bearings, for its excellent characteristics, such as the outstanding tolerance to temperature and wear, good stiffness, high strength, and so on. Surface quality is vital for precision bearings. However, the machining of ceramic materials is difficult due to their high hardness and high brittleness. To investigate the effect

In this work a number of selected, isotropic, invariant-based hyperelastic models are analyzed. The considered constitutive relations of hyperelasticity include the model by Gent (G) and its extension, the so-called generalized Gent model (GG), the exponential-power law model (Exp-PL) and the power law model (PL). The material parameters of the models under study have been identified for eight different

Laser hardening is a very efficient technique for local surface treatment, however, in case of complex and large components robust processing is highly challenging due to limitations in terms of the absolute size of the overall heat-affected zone. As is shown in the present work, an increased in-depth effect can be achieved by tailoring the laser parameters without melting the surface layer. Optimization

For the first time, the novel combination of multi-pass equal channel angular extrusion/pressing (ECAE/P) and selective laser melting (SLM) was investigated. Herein, four passes of ECAP via route Bc at 150 °C were applied as a severe plastic deformation (SPD) technique on the SLM as-built AlSi12 to promote superior mechanical properties. The microstructure and mechanical behavior of AlSi12 fabricated

Residual stress is a severe problem concerning about the service life and the safety of welded structures, which is affected by the assembling and restraint conditions. In this study, the residual stresses of 2219-T8 aluminum alloy butt-welded joints are investigated at different restraint conditions through contour method, which can obtain the 2D map of residual stress on the cross-sectional surface

Micro-holes drilling of titanium alloy using ultrasonic-assisted high-speed drilling (UAHD) has been proven to be effective in improving the height of the exit burr. The height of the exit burr is considered as one of the key output variables to evaluate the machining quality of micro-holes. Investigating the height of the exit burr and its modeling development provides great help to understand the

Machining-induced residual stresses in a part can significantly influence its performance and service time. It is common that the final surface of the part is produced after multiple cuts in the machining process. In multiple cuts, the previous cuts could often generate accumulated strain/stress and temperature on the part surface. These accumulated strain/stress and temperature will be brought to

Inertia friction welding (IFW) is attracting considerable attention in recent years for dissimilar metals joining such as aluminum (Al) alloy to stainless steel due to its ease to control heat input accurately. As a result of thermo-mechanical conditions, the microstructure at the friction interface, especially the brittle IMCs, is usually considered to be non-uniformly distributed. In the present

Small chain resistance butt welding often has unstable welding quality due to high production frequency and short welding time. However, there is still a lack of research on online monitoring of resistance upset butt welding. This study proposes to collect the state information in the welding process and combine with the unsupervised learning method to predict the final welding quality. The collected

Buckle propagation in offshore pipelines is a catastrophic mode of failure critical to the design and operation of such structures. The collapse of a locally weakened section in the pipeline can initiate a buckle that travels at high velocity, flattening long sections of the structure. The propagating buckle velocity increases with the ambient pressure and, as the collapse pressure of the pipe is approached

We investigated the effective surface tension of liquid eutectic gallium indium (EGaIn) with oxide skin. Our visualization of the EGaIn interface during extension and compression indicated the compression causes the wrinkles on the oxide skin, which is then partially smoothed out by extension. We found that the creation of the interface was the combined result of tearing of the oxide skin and the unfolding

Ground reaction force (GRF) plays an integral role in legged robots to control interaction with the ground. However, most techniques in whole-body controller for quadrupedal robots do not explicitly take into account actual torque or force in their control loops and instead use feed-forward force to generate joint torque at every time step. In this paper, we present a closed-loop whole-body controller

This paper addresses the issue of cooperative control concerning the output synchronization of the linear time-invariant multi-input multi-output multi-agent system i.e., multi-unmanned aerial vehicle (a swarm of the drone), by designing observer-based consensus protocol with directed communication topology. Considering the leader following consensus tracking problem, an observer-based protocol is

This paper presents a novel light-weighted Unmanned Aerial Vehicle (UAV), an over-actuated tilt-rotor quadrotor with an innovative control allocation technique, named as Fast Control Allocation (FCA). In this arrangement, every motor has its own independent tilting command angle. By using this novel approach, the aircraft enhances its yawing capability and increases one more actuation domain: forward/backward

The unmanned robotic excavator system has recently become one solution for rescue at the disaster site. Almost all of the solutions about excavator automation have used the electric valve controller and pressure sensor through the mechanical modifications since they are essential. However, some problems might occur because of unpredictable cost and time consumption in modifying the hydraulic drive

The spectral kurtosis (SK) is a useful tool for locating the non-stationary component in the single source signal. It has been verified by the mechanical fault diagnosis. The fast kurtogram (FK) is an improvement method based on the SK. However, for the signals with lower signal noise ratio (SNR), FK is not able to locate the chatter. In this paper, an on-line chatter monitoring using the FK and the

In phase-field models the damage evolution problem is considered as a minimisation problem of a Griffith-like energy functional, governed by the principles of irreversibility, stability and energy balance. Herein, we consider phase-field models characterised by different degradation and energy dissipation functions. With a proper choice for the characteristic functions in phase-field models, it is

A frictional receding contact problem of an infinitely long layer pressed by different finite pressure distributions onto a half-plane of the same linear elastic material is solved with the distributed dislocation technique. Solutions are obtained for when the layer is subject to three different pressure distributions: finite patch of constant pressure, square-root bounded (Hertzian) pressure and square-root

In this work, an innovative two-dimensional (2D) hybrid auxetic elastic metamaterial (MODEL I) with reentrant triangular and chiral structures is proposed to open the broaden bandgap for vibration attenuation. Furthermore, the hybrid reentrant-chiral lattice with embedded resonators (MODEL II) shows multiple bandgaps at ultra-low frequency. Based on theoretical lumped mass-in-mass method and finite

Abstract This article presents an experimental study of colloidal solutions with a focus on the surface properties of colloidal solutions in view of their further application in pulsating heat pipes. Using a tensiometer and the Welhelmi plate method, we carried out a series of measurements of surface tension for various concentrations and temperatures of colloidal solutions with three promising surfactants:

Abstract The paper presents results of an experimental study of the structure of gas-liquid flow in a slit microchannel with a cross section of \(200\times 1205\) \(\mu\)m and an aspect ratio of 1:6. The liquids used were ethanol and distilled water, and the gas was nitrogen; a cross-junction mixer performed the mixing. In the wide ranges of gas and liquid flow rates J\(_\mathrm{liq}=0.02\)–0.1 m/s

Abstract It is shown that theoretical models elaborated for polymer microcomposites are not capable to describe variation of the melt viscosity of polypropylene/globular carbon nanocomposites at change in the nanofiller contents. Then a fractal model of viscosity is proposed, which takes into account the sizes of nanofiller aggregates and their surface structure. This model shows a good agreement with

Abstract Climate change concerns have made the engineering community care more about environmentally friendly working fluids. Currently, the fluid R134a, which has a high global warming potential, is widely used in chiller applications. In this study, several low GWP working fluids, R450A, R513A, R1224yd(Z), and R1234ze(E), are investigated numerically as alternatives to R134a for comparison of their

Abstract Miniature fiber optic sensors were used for detection of initial boiling-up of uniformly superheated liquid in the capillary of a bubble chamber. The possibility of local boiling-up activation by a laser pulse at a single-mode fiber end with a diameter of 9 \(\mu\)m was shown. The object of the study was \(n\)-pentane superheated at 82 K with respect to the liquid-vapor equilibrium temperature

Abstract We scrutinize a steady incompressible natural-convection flow between vertical walls. The modelling equations are solved analytically. Basing on plotted graphs, we discuss the impacts of the chemical reaction, Hall current, and radiation on the fluid velocity, induced magnetic field, current density, temperature field, and concentration. Both the radiation parameter and heat source parameter

Abstract The article presents measurements and calculations of selected gas phase parameters in a liquid metal-gas flow in a magnetic field. The gas phase were argon bubbles, while the liquid metal was the GaInSn eutectic. The flow velocities of the gas bubbles, their equivalent diameter, and drag coefficient values were calculated for different argon inlet nozzles. The boundaries between the rise

Abstract This paper reviews counterflows, double counterflows, and circulation cells in vortex motion and argues that all these seemingly paradoxical phenomena can be caused by a common swirl-decay mechanism (SDM). It is shown that the SDM explains (a) the counterflow of water and oil in hydrocyclones, (b) the elongated counterflow of hot and cold air in vortex tubes, (c) the double counterflow occurring

Abstract This paper presents experimental results on heat transfer efficiency on a flat circular heat-release surface modified using additive technology. A porous plate 500 \(\mu\)m thick, 3D-printed from copper spherical granules with an average diameter of 50 \(\mu\)m, was fixed by means of resistance soldering on a heat-release brass surface of 20 mm in diameter. The heat transfer was investigated

Abstract The article outlines the relevance of production of dried products using a mobile solar dryer plant with mobile shelving. For intensification of the drying process, the convection of the drying agent flow in the proposed design of drying chamber was studied via numerical solution of the Navier–Stokes equations. As a result, a graphical interpretation of isolines of moving stream of drying

Abstract Accurate prediction of the temperature and various species concentrations at combustor exhaust is very important. This work presents numerical investigations of a can-type combustor used in industrial gas turbines for power generation. The methane-air combustion process is investigated using models based on Reynolds-averaged Navier–Stokes (RANS) equations. Enhancement of the mixing of air

Abstract This article is devoted to adhesion forces of polymers modified with silica nanoparticles, as well as studying changes in the surface relief of polymers modified with nanopowders of silicon dioxide, using the atomic force microscope. Enhancement of adhesion forces of nanocomposite samples of polymers containing 1 and 3% of silica nanoparticles was observed despite the non-modified nature of

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

This paper presents a new magnetic levitation system, MagTable, which provides six-degrees-of-freedom (6-DOF) and completely contactless operation of a magnetized object. The MagTable consists of a planar array of square coils and a permanent magnet type carrier. The maximum levitation height of the carrier is 30mm within a 400mm × 200mm horizontal translation range. The novelty of this research lies

Offshore installations e.g.marine transportation, oil platforms, etc., are strongly dependent on sea conditions. To increase the workable time of carrying out these operations, a Stewart platform is installed on a ship to serve as a motion compensation base, and equipment on the base can have the same precision with those on the land-fixed base. Herein, movements of the Stewart platform are influenced

In robotic 3D inspection systems, it is essential to obtain precise measurement results by covering the entire surface area of the target objects. To this end, various view planning methods have been proposed to guarantee complete coverage in order to ensure precise measurements of the target object. However, for precise inspection, in addition to the coverage of the object, globally consistent registration

The hollow polymer microchannels with different shapes and dimensions have been fabricated by the MIMIC method and the heating process for the first time. The smallest cross-sectional dimensions of hollow polymer microchannels were about 2.6 μm in the vertical direction and 3.5 μm in the horizontal direction. The length of hollow polymer microchannels increased parabolically with the heating temperature

Industrial robots can perform delicate operations, and they have good stability and durability. However, robots adapt with difficulty to changes in tasks and environments, and they basically can only perform operations in a fixed logic sequence. In contrast, humans can adapt to changes in the environment at any time due to their strong hand–eye coordination. Humans can quickly adjust their limbs to

Trajectory planning with consideration of surrounding vehicles and decision-making in the middle of complicated manoeuvres are some of the most important challenges regarding the implementation of automated driving. Since transient dynamic traffic conditions was limited to the start of the manoeuvre in previous research, no solution was provided for the surrounding vehicles’ transient changes during

Polyether ether ketone (PEEK) has been widely used in the medical engineering due to its high strength to weight ratio, creep and wear-resistance, and anti-allergically properties. Grinding is generally used to produce PEEK parts with high accuracy and surface quality requirements. In this research, the tool loading and the effect of cryogenic cooling in the grinding of PEEK are studied for the first

The effects of strain rate, size (height × width), and pre-existing crack length on the mechanical response of polycaprolactone electrospun membranes were investigated by tension tests conducted at room temperature. In particular, tensile tests were performed with three different strain rates for strain rate effect tests, seven different geometries for elucidating the size effect, and three different

The present paper introduces an accurate numerical procedure to assess the internal thermal energy generation in an annular porous-finned heat sink from the sole assessment of surface temperature profile using the golden section search technique. All possible heat transfer modes and temperature dependence of all thermal parameters are accounted for in the present nonlinear model. At first, the direct

Accurate posture control of hydraulic roof supports, which use pressurized water as their fluid power source, is an important part and research direction of intelligent fully mechanized mining face. At present, the large flow on/off directional valve used on the hydraulic roof support cannot meet the requirement of precise posture control of the roof support. To overcome the conundrum, a novel two-position

The present work discloses the magnetohydrodynamic pulsating flow of blood-carrying nanoparticles in a channel with the viscous dissipation and Joule heating effects. Couple stress fluid is treated as blood which is the base fluid. The Maxwell Garnett model for thermal conductivity of nanofluid is considered. The thermal radiation and heat source/sink impacts are taken into account. Analytical expressions

A double-end lower limb rehabilitation robot is introduced in the paper, which can realize the rehabilitation training of the abduction and abduction, internal rotation and external rotation of human lower limb. The kinematics and dynamics of the robot are analyzed. Based on the motion trajectory planning of the lower limb rehabilitation robot, the motion state and dynamic state of the cable are analyzed

Current studies on intelligent bearing fault diagnosis based on transfer learning have been fruitful. However, these methods mainly focus on transfer fault diagnosis of bearings under different working conditions. In engineering practice, it is often difficult or even impossible to obtain a large amount of labeled data from some machines, and an intelligent diagnostic method trained by labeled data

Purpose The purpose of this paper is to provide a “Q&A interview” conducted by Joanne Pransky of Industrial Robot Journal as a method to impart the combined technological, business and personal experience of a prominent, industry engineer-turned entrepreneur regarding his pioneering efforts in bringing a robotic invention to market. This paper aims to discuss these issues. Design/methodology/approach