Tangential Force Research Articles

МАТЕМАТИЧНЕ МОДЕЛЮВАННЯ РОБОТИ СУДНОВИХ СТЕРН ПРИ РІЗНИХ РЕЖИМАХ МАНЕВРУВАННЯ

The availability of adequate mathematical models of the ship propulsion system is essential for developing effective ship control systems, building high-quality simulators, and studying the ship’s maneuvering behavior. With the advancement of new computing and information technologies, the mathematical models of the ship propulsion system need to meet higher requirements and cover wider applications. This leads to the need for continuous improvement of mathematical models, especially those of non-inertial forces acting on the ship. This work investigates the influence of the ship’s curvilinear movement on the rudder performance. Mathematical models of the forces and moments acting on the rudder at different values of the local drift angle and the rudder angle are derived. The resultant force on the rudder is decomposed into components due to the rudder lift, drag, normal force, and tangential force. Expressions for the coefficients of rudder hydrodynamic quality, reverse quality, and normal force are obtained. The existing mathematical models of the rudder hydrodynamic coefficients are analyzed and their limitations and applicability are discussed. New mathematical models of the rudder lift and drag coefficients are proposed, which take into account the aspect ratio, relative thickness, and angle of attack of the rudder. The proposed models are validated by comparing them with experimental data for NACA series rudders. t is shown how the lift and drag of the rudder, as well as the components of the resulting force, change for the maximum possible range of changes in the local drift angle and the rudder angle, for different values of the rudder aspect ratio and relative thickness. Keywords: mathematical models, ship rudders, curvilinear movement, longitudinal and transverse components of forces, dimensionless hydrodynamic coefficients.

Tool Wear Mechanism and Grinding Performance for Different Cooling-Lubrication Modes in Grinding of Nickel-Based Superalloys.

Tool wear introduced during grinding nickel-based superalloys was identified as a significant factor affecting the production quality of aero-engine industries concerning high service performance and high precision. Moreover, uncertainties derived from the various cooling-lubrication modes used in grinding operations complicated the assessment of grinding preformation. Therefore, this work investigated the tool wear mechanisms in grinding nickel-based superalloys that adopted five cooling-lubrication modes and investigated how the wear behaviors affected grinding performance. Results showed that chip-deposits covered some areas on the tool surface under dry grinding and accelerated the tool failure, which produced the highest values of tangential force, 7.46 N, and normal force, 14.1 N. Wedge-shape fractures induced by indentation fatigue were found to be the predominant wear mechanism when grinding nickel-based superalloys under flood cooling mode. The application of minimum quantity lubrication-palm oil (MQL-PO), MQL-multilayer graphene (MQL-MG), and MQL-Al2O3 nanoparticles (MQL-Al2O3) formed lubricity oil-film on the tool surface, which improved the capacity of lubrication in the tool-workpiece contact zone and provided 37%, 30%, and 52% higher coefficient of friction than dry mode, respectively. The results of this study demonstrate that lubricated oil-film produced by MQL modes reduces the possibility of fractures of cubic boron nitride (CBN) grits to some extent.

Finite element modeling and experimental validation of turning process using bio-mimicked structured tool for outcomes relevant to industry

Martensitic stainless steels are extensively used in aerospace, medical, and oil and gas industries because of their superior properties such as high hardness, strength, and corrosion resistance properties. However, the machining of this work material becomes difficult due to its high hardness and low thermal conductivity leading to high cutting force requirements and tool wear. Recently, the application of structured tools is one of the sustainable machining techniques used to enhance the machinability of work materials. Most of the researchers have studied only the influence of conventional structured geometries and have mainly concentrated on experiments. But the conduction of experiments involves bulky and costly experimental setups and also consumes a lot of time. Also, the bio-mimicked geometrical shapes and various geometrical parameters of structured tools on machining characteristics of martensitic AISI 420 steel have not been studied. Therefore finite element (FE) modeling proves to be a beneficial technique as it saves time and effort. In the current investigation, a 3D FE model is developed to examine performance of different geometrical structured tools in improving the machinability of AISI 420 steel. Johnson cook (JC) material model is utilized for modeling workpiece. Initially, the tangential force results obtained through simulation are validated with tangential forces obtained through experiments with an error of 6.65% using conventional tool and 5.57% using bio-mimicked structured tool, indicating the suitability of the machining model. Further, the effect of various structure shapes, mainly bio-mimicked crescent structure, dimple structure, and groove structure, was studied, and it is noticed that crescent-structured tool depicted better performances in lowering cutting force, effective stress, and cutting temperature. After getting superior geometry, i.e., crescent-structured geometry, the influence of variation in crescent structure parameters (radius, edge distance) was examined to study its influence on the above-mentioned machining responses. The variation in structure parameters significantly influences various output responses, indicating that bio-mimicked structured tools have a lot of potential to improve the machining performance of AISI 420 steel.

Correlation between surface integrity characteristics in high-speed grinding of Ti-6Al-4V

The present article establishes a fundamental correlation between surface integrity characteristics of the finished surface with the normal to tangential force ratio (Fn/Ft) in the grinding of Ti-6Al-4V. The subsurface deformation, crystallographic texture, surface redeposition, and residual stress were studied in the surface integrity characteristics. The XRD result indicated deformation-induced texturing of the α-002 basal plane of Ti-6Al-4V. The gradual reduction in texturing along the depth was confirmed by the Gi-XRD investigation. The relative intensity of the 002 peak was utilized as a quantitative indicator of subsurface deformation. The XRD and the metallographic study revealed a considerable amount of subsurface deformation at a higher grinding speed (vs ) and an enhanced material removal rate (MRR). Intense surface redeposition was also observed for higher vs and increased MRR grinding conditions. The surface redeposition was identified as an influencing factor that escalates the subsurface deformation and crystallographic texture. In addition, the residual stress was found to be more compressive at enhanced vs and MRR. Further, a higher force ratio Fn/Ft was noticed for the grinding conditions that revealed significant subsurface deformation, strong crystallographic texture, surface redeposition, and more compressive residual stress. Eventually, a correlation was found between the force ratio Fn/Ft and all these surface integrity characteristics.

Experimental investigation on acoustic emission in fretting friction and wear of bolted joints

Fretting between bolted interfaces may change the dynamic characteristics of structures under vibration loading. The acoustic emission (AE) technique has been successfully used to investigate friction and wear mechanisms between different kinds of contact pairs. This paper experimentally investigates the AE signals of a bolted joint structure during friction and long-time fretting wear to explore the relationship between AE characteristics and interface fretting behaviors. A test apparatus dedicated to the study of fretting behaviors of bolted joints together with an AE acquisition system is used to carry out the experimental tests. Relative displacement, tangential friction force and the related AE waveform features are obtained simultaneously to better relate acoustic emission signals with hysteresis loops. The effects of external excitation amplitude and fretting wear cycles are investigated. The frequency signatures of the individual burst acoustic emission event under different excitation amplitudes and wear stages are analyzed. Results show that AE events mainly occur in the micro-slip and the gross-slip regime, and AE technique is more sensitive to the transition point from micro-slip to gross-slip regime. As the external excitation amplitude increases, the value of most AE parameters is gradually increased. As the fretting wear cycles increase, evolutions of bolt preload, frictional coefficients, and AE parameters first show a significant change and then become asymptotically stable. Furthermore, the frequency intensity and range will increase with the increase of excitation amplitude and decrease with the wear cycles.

Particle movement and hydraulic impact in dense two-phase solid–liquid flow inside a water–iron sand jet

High-pressure and multi-phase jet technology is widely used in applications to reduce energy consumption, especially when cleaning steel strips. The dynamics of jet flow and energy transfer in two-phase solid–liquid flow is intricate, particularly in the presence of dense particles. Constructing mathematical models of such interactions is challenging due to the complexity of particle-to-particle and particle-to-fluid contact. An optimized method based on a dense discrete-phase model is proposed to accurately track the movement of dense particles in this study. We used the proposed approach to investigate the movement of particles, the corresponding mechanism of the flow field, and the characteristics of wear while considering the hydraulic forces acting on the particles by using minimal resources for calculation. The results indicate that this method can be used to accurately count an extremely large number of particles and capture their dynamics. The particles acquired kinetic energy from the high-pressure jet, and most of them moved downstream with the main flow. However, part of them migrated toward the bilateral region, participated in the formation and evolution of the vortex, and washed the bottom of a mixture chamber. The impact of the particles at the bottom of a mixing chamber exhibited time-averaged characteristics in terms of the number of collisions and the average normal and tangential forces. The curve of the rate of average wear includes three stages: single-phase flow (no wear), mixed flow (rapid wear), and stable flow (rapid and stable wear at a rate of 9.29 × 10−4 mm/s).

Simulation of a Power Skiving Gear Cutting Process

Abstract The results of the computer simulation of the cutting process of gears by the power skiving method are presented. Following the kinematics of the process, a method for generating 3D geometric models of undeformed sheared layers were developed, and their parameters were analyzed. The influence of tool geometry and technological parameters on cutting conditions is investigated. The simulation results and calculation of the tangential force and torque on the tool axis and their influence on the error due to angular elastic deformation of the tool are given.

Experimental Study on Freezing Strength of Soil-Concrete Lining Interface in Cold Regions

The lining of water conveyance canals in cold regions is usually subjected to serious damage, such as spalling, bulging, and fracture, due to the harsh natural environment. The main causes of these types of damage are the normal frost-heaving force and tangential frost-heaving force (adfreeze force) acting on the liner plate. In this study, the adfreeze forces between the foundation soil and liner plate were studied using the direct shear test, considering the effects of the initial water content, test temperature, and compactness. The results show that the increase of the water content, the increase of the temperature, and the decrease of the compactness increased the interfacial peak shear displacement, and they all varied in the range of 0.3–1.6 mm. With the decrease of the initial water content of the soil sample, the increase of the test temperature, and the decrease of the compactness, the peak shear stress decreased significantly with the amplitude between 51 and 87%. The interfacial cohesion decreased significantly with the increase of the initial water content, the increase of the temperature, and the decrease of the compactness. The interfacial friction angle had no apparent variation pattern. At room temperature, the interfacial friction angle decreased significantly with the increase of the water content. When the water content was 30%, the interfacial friction angle was almost lost completely, which can easily lead to the sliding loss of the foundation soil and further damage, such as the instability of the lining.

Controlling solar radiation forces with graphene in plasmonic metasurface

Controlling and harvesting solar radiation pressure is a significant challenge, however, there are a few potential solutions, which are suitable for several key applications. In this study, an electrically tunable plasmonic metasurface is designed for the visible spectrum. Moreover, the normal and the tangential optical forces acting on the metasurface are calculated. Whilst presenting high efficiency in the anomalous reflection, the designed active metasurface provides tunability of optical forces acting on the metasurface. The metasurface is composed of tapered silver cells embedded on top of the graphene layer with 20 layers of graphene sheets. Hence, the transferred momentum to the metasurface can be controlled by tuning the Fermi level of graphene sheets. Our results can provide a suitable platform for optical force control desired in tunable radiation pressure harvesting, micro vehicles, solar sailing, and optical tweezers.

A study on high-shear and low-pressure grinding with body-armour-like abrasive tool (BAAT) for Inconel 718 superalloys

A novel body-armour-like abrasive tool (BAAT) was developed for the high-shear and low-pressure grinding of super alloys with an aim to reduce the ratio of normal force to tangential force. A composite process model was developed based on finite element method (FEM) method whereby. Shear thickening fluid (STF) inside the BAAT was set as variable viscosity through TABULAR approach. An experimental platform was established to explore the effects of high-shear and low-pressure grinding process on Inconel 718 specimens. The surface roughness and surface morphology of Inconel 718 specimens were examined. The experimental results were validated against the developed process model outcomes to demonstrate the efficacy. It was determined that the force ratio increased from 0.12 to 0.48 with the computational model while the force ratio experimentally enhanced from 0.298 to 0.577. The results from the computational model was consistent with the experimental outcomes which signifies the effectiveness of developed process model. Even from experimental results, it was evaluated that the surface roughness (Ra) reduced from 0.744 μm to 0.201 μm after removal of horizontal scratches and elimination of vertical processing texture. Inconel 718 specimens exhibited fine surface quality which represented that BAAT acquired desirable characteristics of processing under high-shear and low-pressure environment with excellent grinding performance.

Nozzle Jet Deviation from Bucket Pitch Circle’s Effect on the Stability and Efficiency of Pelton Turbine

During the operation of a Pelton turbine, the centerline of the nozzle jet may deviate from the bucket pitch circle due to the low installation and maintenance accuracy, which will reduce the operating efficiency and the stability of the turbine and even cause severe vibrations and damages. Based on the VOF (Volume of Fluid) two-phase flow model and the SST k-ω turbulence model, the flow characteristics of a Pelton turbine were simulated with the nozzle jet deviating from the bucket pitch circle. The pressure pulsation inside the bucket and the force distribution of the runner were obtained, the turbine oscillation and efficiency were measured before and after the jet deviation, and the effects of the radial and axial deviations on the stability and efficiency of the Pelton turbine were analyzed. The results show that both the radial and axial deviations of the jet cause a significant increase in the axial force and the pressure pulsation amplitude of the turbine; the radial and tangential forces on the runner are slightly reduced; the maximum axial force on the runner is increased by 4 times and 2 times, respectively, after the axial and radial deviations within the maximum value allowed by the industry standard; and the efficiency of the turbine is reduced by 0.4% and 0.3%, respectively. The maximum relative amplitude of pressure pulsation in the radial offset case appears in the center of the bucket blade, while the axial offset case causes uneven pressure distribution on both sides of the diverter blade, uneven force on the bucket blade of the runner, and fatigue damage. By comparing the operation of the runner under the two offset cases, we can find that the axial offset of the jet has a greater impact on the stability of the runner than the radial offset, and the unit is more prone to vibration, increasing the risk of the unit lifting.

Effect of casting modification materials on cutting forces of an Al12Si alloy used in aircraft technology

Abstract In this study, the effect of modification Al-12Si (Etial 140) casting alloy with Al10Sr, CuSn5, and Al10Sr + CuSn5 master alloys has been investigated with respect to the cutting forces. In order to characterize the morphology of materials used in this study, metallography, hardness, density tests, and chemical analysis were performed. An optical microscope was used to examine the microstructure of the samples. Machinability tests were performed with the turning method by using a titanium diboride-coated cementite carbide cutting tool. All experiments were carried out under dry machining conditions with three different cutting speeds and feed rates with a constant cut depth. After the turning test, scanning electron microscope (SEM) images were used to examine the build-up edge (BUE) formation on the cutting tool. It was determined that the modification process has a positive effect on increasing the density and hardness. According to the results, it was observed that cutting (Fc), feed (Ff), and tangential (Fr) forces decreased for all material groups with increasing cutting speed V. Furthermore, Fc, Ff, and Fr forces increased for all material groups with increasing feed rate f. Finally, the highest cutting forces were observed on the Etial 140 c + Al10Sr master alloy.

An approach of micro-slip modeling based on asymmetric contact pressure distribution and its application in nonlinear boundary beam system

A novel micro-slip friction modeling approach based on the Iwan model is presented here. The normal load and tangential stiffness are reassigned reasonably to obtain the tangential force–displacement expression, and the relationship between the asymmetry of contact pressure distribution and the Iwan density function is established. The micro-slip model depends on the distribution of contact pressure, and has the ability to degenerate into a macro-slip model. Based on the model, a simplified non-linear dynamics model of a rotating blade with a dovetail joint is developed, and its effectiveness is verified by comparing it with a relevant reference. The first-order bending vibration of the blade under distributed excitation is analyzed. The results indicate that the pressure distribution of the contact interface has a significant effect on the amplitude–frequency response of the blade and the contact behavior on the joint interface. Compared with the proposed micro-slip model, the single point contact model overestimates the response amplitude. The amplitude–frequency curve obtained by this model is obviously different from the macro-slip model. It is proved that the micro-slip model can more accurately simulate the nonlinear vibration characteristics of tenoned blades, which provides new insights for the study of the vibration characteristics of tenoned blades.

Modeling and analysis of tangential force in robot abrasive belt grinding of nickel-based superalloy

Modeling and analysis of tangential force in robot abrasive belt grinding of nickel-based superalloy

Forced Wetting Properties of Bacteria-Laden Droplets Experiencing Initial Evaporation.

Microbial adhesion and spreading on surfaces are crucial aspects in environmental and industrial settings being also the early stage of complex surface-attached microbial communities known as biofilms. In this work, Pseudomonas fluorescens-laden droplets on hydrophilic substrates (glass coupons) are allowed to partially evaporate before running wetting measurements, to study the effect of evaporation on their interfacial behavior during spillover or splashing. Forced wetting is investigated by imposing controlled centrifugal forces, using a novel rotatory device (Kerberos). At a defined evaporation time, results for the critical tangential force required for the inception of sliding are presented. Microbe-laden droplets exhibit different wetting/spreading properties as a function of the imposed evaporation times. It is found that evaporation is slowed down in bacterial droplets with respect to nutrient medium ones. After sufficient drying times, bacteria accumulate at droplet edges, affecting the droplet shape and thus depinning during forced wetting tests. Droplet rear part does not pin during the rotation test, while only the front part advances and spreads along the force direction. Quantitative results obtained from the well-known Furmidge's equation reveal that force for sliding inception increases as evaporation time increases. This study can be of support for control of biofilm contamination and removal and possible design of antimicrobial/antibiofouling surfaces.

Transient and Steady-State Performance Improvement of IM Drives Based on Dual-Torque Model

Transient response performance and steady-state operation performance are the two most important performance indicators of a motor drive system. In order to solve these two problems, this study proposes a new induction motor (IM) model, and then designs a new simplified linearization controller method. First, the tangential force that determines the transient process of the motor is represented by electromagnetic torque, and the radial force is represented by reactive torque. Then, the dual-torque model of IM is derived, which not only accurately shows the rotating air-gap magnetic field through the amplitude and rotating angular frequency, but also visually demonstrates the physical essence of the transient process of IM. Then, this study proposes a simplified feedback linearization method without the analysis of zero dynamic. In addition, a time-scale hierarchical control system is designed to reduce the ripple caused by the coupling of different time-scale variables. The experimental results show that the steady-state torque ripple of the proposed method is 65% lower than that of RFOC, and the torque response speed is 10% higher than that of DTC.

Grinding performance evaluation of SiC ceramic by bird feather-like structure diamond grinding wheel

In recent years, the diamond grinding wheel has become the primary tool to process hard and brittle materials. A promising technology for enhancing grinding performance is surface-structured grinding wheels. A novel laser simulation bird feather-structured bronze bond diamond grinding wheel is suggested in this paper. It provides outstanding drag reduction and diversion effects since it is based on the structure of bird feathers. The bionic swallows' secondary feathers prototype was ablated on the bronze-bonded diamond grinding wheel by the pulse laser. The grinding processing mechanism of silicon carbide ceramics with a feather-like structured grinding wheel (FLSGW) was analyzed. The grinding performance of FLSGW, V-shaped structured grinding wheel (VSSGW), and a traditional grinding wheel (TGW) grinding silicon carbide ceramics were compared. The effect of FLSGW on the grinding force, workpiece surface quality, and wheel wear were investigated. The results show that FLSGW can reduce normal and tangential grinding forces by up to 56.3 % and 47.7 %, respectively, when compared to TGW. Furthermore, FLSGW has a higher workpiece surface quality than TGW and VSSGW. The FLSGW has significantly less abrasive wear than the of VSSGW and TGW.

Parameter Study on Force Curves of Assembled Electronic Components on Foils during Injection Overmolding Using Simulation.

The integration of assembled foils in injection-molded parts is a challenging step. Such assembled foils typically comprise a plastic foil on which a circuit board is printed and electronic components are mounted. Those components can detach during overmolding when high pressures and shear stresses prevail due to the injected viscous thermoplastic melt. Hence, the molding settings significantly impact such parts' successful, damage-free manufacturing. In this paper, a virtual parameter study was performed using injection molding software in which 1206-sized components were overmolded in a plate mold using polycarbonate (PC). In addition, experimental injection molding tests of that design and shear and peel tests were made. The simulated forces increased with decreasing mold thickness and melt temperature and increasing injection speed. The calculated tangential forces in the initial stage of overmolding ranged from 1.3 N to 7.3 N, depending on the setting used. However, the experimental at room temperature-obtained shear forces at break were at least 22 N. Yet, detached components were present in most of the experimentally overmolded foils. Hence, the shear tests performed at room temperature can only provide limited information. In addition, there might be a peel-like load case during overmolding where the flexible foil might bend during overmolding.

Three-dimensional force-tactile sensors based on embedded fiber Bragg gratings in anisotropic materials.

Three-dimensional force-tactile sensors have attracted much attention for their great potential in the applications of human-computer interaction and bionic intelligent robotics. Herein, a flexible haptic sensor based on dual fiber Bragg gratings (FBGs) embedded in a bionic anisotropic material is proposed for the detection of 3D forces. To achieve the discrimination of normal and tangential force angles and magnitudes, FBGs were orthogonally embedded in a flexible silicone cylinder for force determination. Fe3O4 nanoparticles were used as a modifying agent to induce anisotropic elasticity of the silicone structure to improve the angle detection resolution. The results show that the flexible tactile sensor can detect the angle and magnitude of the 3D force.

MOREL-LAVALLÉE LESION INDUCED BY DYNAMIC HIP SCREW (DHS) CUT OUT: A CASE REPORT AND LITERATURE REVIEW

A Morel-Lavallee lesion (MLL) is a benign cystic lesion that occurs due to injury to the soft-tissue envelope's perforating vascular and lymphatic systems, resulting in a distinctive hemolymphatic fluid accumulation between the tissue layers. The MLL has the potential to make a significant impact on the treatment of orthopaedic injuries.A 79-year-old male patient community ambulatory with assisting aid (cane) known case of Diabetes mellitus, hypertension, bronchial asthma and ischemic heart disease. He was brought to the Emergency, complaining of right hip discomfort and burning sensation for the last 5 days with no history of recent trauma at all. Patient had history of right trochanteric femur fracture 3 years ago, treated with DHS in a privet service. Clinical and Radiological assessment showed that the patient mostly has acute MLL due to lag screw cut out. We offered the patient the surgical intervention, but he refused despite explaining the risks of complications if not treated and preferred to receive the conservative treatment. Compression therapy management explained to him including biker's shorts (instructed to be worn full-time a day) and regular follow up in clinic. Symptom's improvement was reported by the patient in the subsequent visits.In the polytrauma patient, a delayed diagnosis of these lesions is conceivable due to the presence of more visible injuries. It's located over the greater trochanter more commonly, but sometimes in other areas such as the lower lumbar region, the thigh, or the calf. Incorrect or delayed diagnosis and care can have unfavorable outcomes such as infection, pseudocyst development, and cosmetologically deformity. Magnetic resonance imaging (MRI) and ultrasound will aid in MLL diagnosis. However, the effectiveness of MLL therapy remains debatable.We strongly believe that the MLL caused due to tangential shear forces applied to the soft tissue leads to accumulation of the blood and/or lymph between the subcutaneous and overlying fascia and it often misdiagnosed due to other distracting injuries. Nontheless, in our case we reported MLL occur due to internal pressure on the fascia caused by cut out of DHS lag screw.