Curvature Of Plate Research Articles

Initial framework design of a digital twin mixed-reality-application on human-robot bi-directional collaboration for forming double curvature plate

This paper explores and identifies commonalities among recent Digital Twin (DT) technology definitions. additionally, it introduces a framework for a digital twin of Human-Robot Collaboration (HRC) focusing on English wheel manufacturing as its foundational context. To achieve this, two 3D simulators, namely Grasshopper and Rhino, were employed to faithfully replicate the English wheel process digitally. Subsequently, optimizing these simulators’ performance paved the way for a comprehensive visualization of the English wheel using the Microsoft HoloLens. This visualization integrates digital and physical interactions, resulting in a mixed reality environment. The ultimate goal of this research is to enable a bi-directional collaboration within the digital representation of the English wheel, bridging the gap between the virtual and physical realms.

Rapid identification of the coefficient of moisture expansion of polymer materials by the employment of plates with asymmetric concentration fields

The paper pursues the development of a novel methodology for the rapid identification of the diffuso-mechanical properties of polymer materials based on the employment of plates subject to asymmetric moisture concentration fields. The study is carried out on epoxy plate samples equipped with a thin aluminium foil on a surface exposed to the environment to promote asymmetric moisture absorption. The asymmetric moisture fields promote deformations of the plate. Mass gain and plate curvatures are measured as a function of time during conditioning. By using a weakly coupled diffuso-mechanical model: 1D Fick’s diffusion model and 2D plane stress hygroelastic model the diffuso-mechanical properties of the material can be then identified. Due to the chosen size of the experimental samples the present study allows the identification of the coefficient of moisture expansion of the epoxy material. For the material under study, the following values can be identified for saturation mass gain, water diffusivity and coefficient of moisture expansion respectively: 1.67%, 0.025 mm2.h−1, 0.1628.

Influence of the carbon fiber plate curvature of advanced footwear technology on the running energetic cost and 3000-m performance

This study aimed to explore the effect of two similar commercialized advanced footwear technology models differing mainly in their plate geometry (i.e., low and high curvature plate) on the running energetic cost in both non-fatigued and fatigued states. It also sought to determine their impacts on 3000-m performance. Twelve highly trained male athletes performed four 5-min trials (two advanced technology models, two trials). In each experimental session, athletes completed a 3000-m trial which was followed by a 5-min trial to test the running energetic cost when fatigued. Athletes exhibited a lower running energetic cost when wearing the low curvature plate in a non-fatigued state (P = 0.034; − 1.13 [− 1.92 to − 0.11] %), which persisted with better performance in the 3000-m trial (P = 0.017; − 0.42 [− 0.74 to − 0.09] %). However, in a fatigued state, non-significant differences were reported (P = 0.207). The low curvature plate seems to be more effective than the high curvature plate when running at low intensity in a fresh state as well as in a maximal high-intensity effort. However, non-significant differences between plate geometries were observed when fatigue was increased.

Contact acoustic nonlinearity and damping properties of completely free vibrating curved and delaminated CFRP plates

This study reports an experimental investigation on the effect of plate curvature and circular inter-ply delamination on the completely free vibration properties of carbon fiber reinforced polymer (CFRP) plates. Impact tests on wire suspended plates were performed and variations in measured natural frequencies and modal damping are reported. Delamination clapping type contact acoustic nonlinearity (CAN) was observed in the presence of a series of higher harmonics in the vibration spectrum. These higher harmonics consisted of five to seven equally distanced peaks grouped in a frequency range of around the double of odd mode M (5,0). Modal damping was highly sensitive to delamination which caused a 33% average increase in damping loss factors. Odd mode M (3,0) was the most affected with an average increase of 51% in damping loss factor, explained by the delamination location relative to the wavelength of that mode shape. Natural frequencies were less sensitive to delamination, on average decreasing 1.0% in flat plates and increasing 3.1% in curved plates. The modal frequencies calculated from embedded fiber optic sensor (FOS) or electrical resistance strain gauge signals agreed with finite element modeling (FEM) to within a 3.1% difference for all modes considered. The damping loss factors deducted from suspended plate tests were consistent with complementary results from dynamic mechanical analysis (DMA). The measured delamination clapping CAN and its related influence on damping can serve to enhance structural health monitoring (SHM) methods.

Influence of the main parameters of laser impact forming on the bending of plates

Laser impact forming (LIF), in which a shock wave deforms a thin plate, is studied. The LIF process is simulated using the finite element method. It is established that the maximum bending curvature of the plate can be obtained by adjusting the overlap coefficient of laser spots, the number of repeated laser pulses, and the power density of the laser beam. Keywords:laser impact forming, finite element method, residual stresses, bending, plate curvature sakhvadze@mail.ru

Are TomoFix Locking Plates Really Anatomical for Indian Population?

The use of a TomoFix plate can be a challenge in Asian population who inherently have smaller tibial bones. This study aims to find out the normal proximal tibial morphometric measurements in Indian population and to compare the Medial Anterior Radius of Curvature (MAROC) of proximal tibia with the Proximal Part Radius of Curvature (PPROC) of the available TomoFix plates, to estimate conformity of the fit between them. Retrospective Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) based proximal tibial measurements were performed on 824 knees, 664 females and 160 males (604 patients). The mean MAROC, mean MAROC in males and mean MAROC in females were compared to the PPROC of TomoFix plates. The radiological measurements revealed a mean AP length of 45.22 ± 3.79mm, mean ML width of 69.04 ± 5.01mm and mean MAROC of 21.88 ± 2.11mm. The mean MAROC in males was 24.07 ± 2.1mm, whereas in females it was 21.35 ± 1.75mm. The mean MAROC, mean MAROC in males and mean MAROC in females when compared to the PPROC of Standard TomoFix plate (38mm), Small TomoFix and Anatomical TomoFix plates (30mm) showed a significant difference (p < 0.01), indicating that the radius of curvature of the plate does not match the radius of curvature of the anteromedial tibial plateau. The TomoFix plates, including Small (Asian Version) and Anatomical plates, are relatively large for the Indian population. Our study may help the implant to designers develop a plate that will better suit the Indian population, improving results and reducing hardware-related complications of MOWHTO.

Controls on Bending‐Related Faulting Offshore of the Alaska Peninsula

AbstractOceanic plates experience extensive normal faulting as they bend and subduct, enabling fracturing of the incoming lithosphere. Debate remains about the relative importance of pre‐existing faults, plate curvature and other factors controlling the extent and style of bending‐related faulting. The subduction zone off the Alaska Peninsula is an ideal place to investigate controls on bending faulting as the orientation of the abyssal‐hill fabric with respect to the trench and plate curvature vary along the margin. Here, we characterize faulting between longitudes 161°W and 155°W using newly collected multibeam bathymetry data. We also use a compilation of seismic reflection data to constrain patterns of sediment thickness on the incoming plate. Although sediment thickness increases over 1 km from 156°W to 160°W, most sediments were deposited prior to the onset of bending faulting and thus should have limited impact on the expression of bend‐related fault strikes and throws in bathymetry data. Where magnetic anomalies trend subparallel to the trench (&lt;30°) west of ∼156°W, bending faults parallel magnetic anomalies, implying that bending faults reactivate pre‐existing structures. Where magnetic anomalies are highly oblique (&gt;30°) to the trench east of 156°W, no bending faults are observed. Summed fault throws increase to the west, including where pre‐existing structure orientations are constant (between 157 and 161°W), suggesting that another factor such as the increase in slab curvature must influence bending faulting. However, the westward increase in summed fault throws is more abrupt than expected for gradual changes in slab bending alone, suggesting potential feedbacks between pre‐existing structures, slab dip, and faulting.

Ultrasound clinical references of the healthy toenail unit.

The toenail unit, commonly called the nail, is one of the most frequently examined and treated structures in clinical podiatry. Ultrasound is a standard clinical technique because it is a noninvasive, painless, and rapid diagnostic tool. The main objective of this study was to obtain morphometric data of the healthy toenail unit by ultrasound for clinical application. The nails of 76 participants (152 hallux nails; 38 men, 38 women, average age 26.83 ± 12.20) were examined using a VINNO E35 ultrasound system and an X6-16L linear probe with a frequency of 18 MHz. Five ultrasound measures of the healthy toenail unit were obtained, of which only the distance from the center of the distal phalange to the nail plate varied with age, sex, weight, and foot (p-values ≤ 0.050). The other four parameters were less influenced by the variables analyzed, except sex, which influenced nearly all (p-values ≤ 0.050). In one of these variables, indications of significance were observed (p-values = 0.060), with greater distances in the men than in the women, except for nail plate curvature, which showed a higher value. The other variables studied did not influence the parameters analyzed. High-frequency ultrasound can be used to examine the healthy toenail unit and define anthropometric reference measurements that can be used for more accurate and comparative diagnosis.

Numerical Study of the Influence of Different Bending Shapes on the Heat Transfer Characteristics of Annular Cross Wavy Primary Surface Recuperator (CW-PSR)

The cross-wave primary surface recuperator (CW-PSR) is a dependable option as a recuperator for micro gas turbines (MGT). The micro CW-PSR studied in this paper is composed of 171 stacked curved plates, with each plate containing 33 micro heat transfer channels with equivalent diameters of less than 1 mm. In this study, the influence of bending curvature on the thermal performance of CW-PSR plates is investigated through three-dimensional numerical simulation with fluid–solid–thermal coupling. The results indicate that the variation in bending curvature studied can result in a noteworthy 8% difference in the total heat transfer coefficient of CW-PSR plates. A direct correlation between heat transfer capacity and secondary flow strength is derived mathematically, explaining the mechanism by which secondary flow enhances heat transfer. By employing this relationship, a comprehensive analysis of CW-PSR plates with diverse bending curvatures is conducted, effectively showcasing how curvature influences the secondary flow pattern and enhances the channel’s heat transfer capacity. In addition, this paper considers the comprehensive influence of the size parameters of the heat transfer unit and the bending curvature of the heat transfer plate on the heat transfer and flow characteristics of the CW-PSR, and a dominant mathematical expression is obtained, which can be used for the design of similar heat exchangers of the same type.

Finite-Element Modeling of Laser Shock Forming Technology

Laser shock forming is an innovative technology in which a laser shock wave induces a flexural deformation of a thin plate. Naturally, the technology of laser shock forming cannot increase the curvature of the plates indefinitely and its possibilities have limits, especially for thick plates. This article investigates the maximum convex flexural curvature of a plate that can be achieved using the technology of laser shock forming by successively increasing its main characteristics: the laser spot overlap factor, the number of repetitive laser pulses, and the intensity of laser power density. The resulting flexural torque and bending curvature are calculated from the average residual stresses obtained by the finite element method. The proposed method for predicting the plate curvature can effectively predict the flexural behavior of the plate. This allows one to plan the process of laser shock forming properly.

Induced charge electro-osmotic mixing performance of viscoelastic fluids in microchannels with an electrically conductive plate

Micromixers have important applications in lab-on-a-chip, biomanufacturing, and chemical engineering. In this study, a micromixer with a conductive barrier plate based on the induced charge electro-osmosis is proposed. The Oldroyd-B constitutive model was chosen to characterize the flow characteristics of viscoelastic fluids, and the Poisson–Boltzmann model was used to characterize the electrokinetic properties. The effects of the installation of the conductive plate, the concentration of the polymer, and the shape of the conductive plate on the mixing were studied based on the finite volume method. The mixing efficiency of the viscoelastic fluids is 78.3% when a non-conductive plate is placed in the micromixer. However, placing a conductive plate increases the mixing efficiency to 89.8%. As the polymer concentration increases, the mixing efficiency increases, which is attributed to the elastic instability. As the curvature of the conductive plate increases from 0° to 360°, the mixing efficiency of the Newtonian fluid increases by 2.82%, while that of the polyacrylamide solutions at concentrations of 100 and 250 ppm increases by 5.31% and 1.97%, respectively.

Plate Mill Stand Electric Drive Control in Asymmetrical Rolling Mode of the Strip Plate Head

An urgent problem that arises in rolling flat steel and plates is to form the preset strip plate head skid-shaped curvature. This is implemented by adjusting the ratio (mismatch) between the top and bottom rolls in the rolling mill horizontal stands. The factors influencing the strip plate head curvature at the stand exit are listed. With reference to the 5000 plate mill of PJSC Magnitogorsk Iron and Steel Works, the article analyzes the top and bottom roll speeds in the “skid” formation mode. The main drawback of the existing electric drive control system is that it controls the speeds as a function of the difference between their current (actual) values. This results in that the drive of one roll reaches a limitation with loss of motor controllability and uncontrolled strip plate curvature. To eliminate this drawback, a new control method was developed, according to which the electric drive speeds are adjusted as a function of the difference between the speed setpoint signals at the inputs of speed controllers. The control system structure implementing this method is considered. The results of simulating the gripping modes with the simultaneous “skid” formation are presented, and the similar experimental oscillograms are considered. It is shown that with the new control algorithm, the electric drive speeds are closer to their setpoint values. This results in better curvature formation accuracy at lower preset “skid” values. Recommendations for tuning the control system are given.

Mechanical strength and nature of lithospheric deformation beneath the rifted sedimentary basins of the east India passive margin

The study of gravity signatures corresponding to sediment load over the passive margins is helpful to constrain the mechanical properties of continental rift systems as well as the adjacent ocean basins. Seismic reflection, free-air gravity and well information from the East India Passive Margin (EIPM) are investigated through spectral approach and 2D process-oriented gravity modelling for quantifying effective elastic plate thickness (Te) to understand the rift mechanisms and the sedimentary basins evolution. The characteristics of lithosphere within the major structural domains along the margin are quite variable. A narrow necking zone (40 km) in the southern segment, and approximately a 70 km hyper-thinned and exhumed domains are inferred in the central segment, while a narrow hyper-thinned domain (30–35 km) is observed in the northern segment of the margin. The southern segment of EIPM, adjacent to Southern Granulite Terrain has low Te values ranging from 5 to 10 km. The segment in the central margin, offshore Dharwar Craton has moderate Te values of 15–20 km. And the northern segment adjacent to onshore Eastern Ghats Mobile Belt has relatively high mechanical strength with Te values ranging from 25 to 35 km. The pattern of Te values and extent of major structural domains along the margin indicates that the southern, central and northern segments evolved as three different modes of rifting such as transform, hyperextended and hypoextended, respectively. In the oceanic domain, the lithospheric strength broadly increases with age following the thermal induced cooling plate model (600 °C isotherm). The thick sedimentary basin of the Bay of Bengal had attained the high value of elastic thickness (Te > 45 km) in the last 23 Myrs. The significant rheological strengthening of the oceanic lithosphere may be attribute to the following reasons: 1) increase in shear-wave velocity anomaly at a depth of 150 km and upper mantle density, 2) change in plate curvature caused by excessive deposition of Bengal Fan sediments in the deep ocean basins and subduction of oceanic plate under the Eurasian plate near the Bengal Fan and 3) modification of stress state of the lithosphere as a convergent interaction of the Indian plate with SE Asia.

Numerical Investigation of Distributed Speed Feedback Control of Turbulent Boundary Layer Excitation Curved Plates Radiation Noise

The control of decentralized velocity feedback on curved aircraft plates under turbulent boundary layer excitations is numerically investigated in this paper. Sixteen active control units are set on the plate to reduce the vibration and sound radiation of the plate. The computational results from the two methods are compared to verify the accuracy of the numerical model. The plate kinetic energy and the radiated sound power under turbulent boundary layer and control unit excitations are analyzed. The influences of control unit distribution, plate thickness and curvature on radiated sound are discussed. Unlike a flat plate, the control of the lower-order high radiation modes of a curved plate under TBL excitations is critical since these modes predominate the sound radiations. The control of these modes, however, is sensitive to the ratio of the stiffness associated with the membrane tensions to the stiffness associated with the bending forces. This ratio implies that the plate curvature and the thickness play an important role in the control effect. When the plate is thinner and the radius is smaller, the control is less effective.

Ingrown Finger Nail-A Lesser Known Entity.

Dear Editor, Ingrown toenails are a common problem encountered in dermatology practice. They are caused by three major factors—excessive transverse curvature of the nail plate, maceration of the gutter and external pressure over the toe nail. In addition, the hard hyperkeratotic transversely over-curved nail plate exerts pressure and its spicule causes penetrative injury to the nail gutter under the influence of external pressure caused by running, tight fitting shoes, standing on toes etc., making the condition worsen.[1] All these factors make toes more vulnerable to having ingrown nails as compared to fingers nails. However, we have been seen few cases of ingrown fingernails in our dermatology out patient department.[2] There is a lack of scientific data on the incidence of ingrown nails on fingers. As per a recent report, finger ingrown nails were more commonly found in patients receiving epidermal growth factor receptor inhibitors (which leads to epidermolysis and easy maceration of the nail gutter).[3,4] In addition, there are some others drugs which may cause paronychia, excessive nail fold granulation tissue (pseudopyogenic granuloma)and eventually ingrown nail development, for example, cyclosporine, docetaxel, doxorubin, oral antifungals, lamivudine, indinavir, ritonavir, azidothymidine, vandetanib, capecitabine, cetuximab, giftinib, and retinoids. The main predisposing causes of ingrown finger nails may be occupation related, such as external pressure of the nail plate on its gutter during writing with the middle and ring finger, stitching, sewing, opening and shutting sliding windows, typing, vegetable cutting etc. It has been observed that ingrown finger nails are more common in the ring and middle fingers than in the index finger, which may be due to the fact that the ring and middle finger nails are more curved as compared to the index finger. Many patients diagnosed with finger nail paronychia on the distal lateral end may have ingrown nails, which might have been overlooked in the initial stage [Figure 1]. So, a careful examination of the finger nail is a must in all cases of distal end paronychia of the finger nail [Figure 2]. A change in the way fingers are used and avoiding repeated trauma in day-to-day activities are necessary for remission in such cases.Figure 1:: Ingrown finger nail in the initial stage is cut and removed from the gutterFigure 2:: Ingrown finger nail with pseudopyogenic granulomaAcknowledgment None. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.

An Effect of a Porous Structure, Slip Velocity and Rosensweig’s Viscosity on the Ferrofluid Based Squeeze Film in Porous Curved Annular Plates

An endeavor has been made to analyze porous squeeze film performance in curved annular plates considering slip velocity, Kozeny-Carman’s porous structure and Rosensweig’s viscosity in Shliomis model-based magnetic fluid lubrication. The globular sphere model of Kozeny-Carman for porous facing is adopted here. An extension of the Einstein’s viscosity for ferrofluid proposed by Rosensweig is considered here to improve the viscosity of ferrofluid for the Shliomis model, while Beavers and Joseph’s slip model is used for evaluating the slip effect. The pressure and load lifting capacity in dimensionless form is obtained by modifying the Reynolds equation incorporating the Rosensweig’s viscosity, Kozeny-Carman’s model-based porosity, slip and Shliomis model-based ferofluid lubrication. The graphical representation reveals that load carrying capacity (LCC) can be increased by increasing the curvature of upper plates, volume concentration and magnetization parameter but decrease with the slip velocity, porous structure parameter and porosity parameter. This study indicates that the load-bearing capacity remains higher as compared to the case of Einstein’s viscosity model. However, this investigation conclusively establishes that the Shliomis model goes ahead of the other two magnetic fluid flow models in overall improvement of bearing performance characteristics. Interestingly, even considerable amount of slip may not pose a serious problem when Kozeny-Carman’s model is resorted to. This investigation reveals that this type of bearing system sustains good amount of load even in the absence of flow which does not happen in the case of conventional bearing system.

Trajectories of principal stresses after plastic deformation

Improving research efficiency of mechanical stresses in metals can be achieved by studying and taking into account the fields of the trajectories of the main stresses (isostats), which qualitatively characterize the stress state. The purpose of the work was to determine the possibility of detecting the isostates in a St3 steel sample, following its plastic deformation. The methodology is based on the magnetoelastic method, manifested by the dependence of magnetic permeability of ferromagnetic materials upon mechanical stresses, acting in them. The method is implemented using the IMN-4M monophase magnetoelastic meter of mechanical stress: the base of the device gage is 5 mm, the angle meter error is ± 2°. The sample is a plate with dimensions of 150 x 150 x 4 mm. Coordinate grids with 10 x 10 mm cells were applied to its front and back surfaces. Using the IMN-4M device, we measured the values of tilt angles for tangents to principal stress trajectories in all nodes, then we created isostates by consecutive adjustment of the direction and radius of curvature for a raised curve. The plastic deformation of a plate was performed by shooting small lead pellets with kinetic energy of 1916 J. The maximum plate curvature in the impact zone of main charge equaled 7 mm. After a shot, the measurements were repeated in the same nodes of coordinate grids, and the isostates were plotted again. The experiment has shown that: the magnetoelastic method makes it possible to detect the isostates even after plastic deformation; the trajectories are present both on front and back surfaces of the deformed plate; isotropic points and parallel isostates are available in fields, formed by the shot. Izotropic zones were formed on front and back surfaces, in which isostates can not be plotted due to random orientation of tangents. The "disturbances" of fields with disruption of regular trajectory flows were detected. The results of the work may be useful for researchers and technical engineers, engaged in the study of elastic and plastic deformations.

Development and perspectives of rolling of rib stiffened plate

Thin-wide aluminium rib stiffened plate structure reduces the weight and provides high stiffness, which makes it in high demand in transportation vehicles, marine, and structural applications for energy saving and CO2 emission reduction. In this study, the applicability of rolling in manufacturing an integral rib stiffened plate is reviewed through analysis of different rolling processes. The effect of rolling parameters and rib geometry on the formation and quality of ribs are analysed. The analysis provides an important basis to advance the understanding of metal flow, viscoplastic deformation and roll shape design during rolling, significantly helping the design of an innovative rolling process for rib stiffened plate. In addition, geometry and rolling parameters, plate curvature, and roll pass design (RPD), that highly affect the rolling process design are discussed. This paper presents the limitations and improvements of specific shape rolling processes and preliminarily concludes that rolling could be a potential method to produce high quality thin-wide panels with high stiffeners.

A simple force balance model of subduction initiation

SUMMARY The initiation and development of subduction zones are associated with substantial stress changes both within plates and at plate boundaries. We formulate a simple analytical model based on the force balance equation of a subduction zone, and validate it with numerical calculations of highly non-linear, coupled thermomechanical system. With two kinds of boundary conditions with either fixed velocity or fixed force in the far-field, we quantitatively analyse the role of each component in the force balance equation, including slab pull, interplate friction, plate bending and basal traction, on the kinematics and stress state of a subducting plate. Based on the numerical and analytical models, we discuss the evolution of plate curvature, the role of plastic yielding and elasticity, and how different factors affect the timing of subduction initiation. We demonstrate with the presence of plastic yielding for a plate of thickness, H, that the bending force is proportional to H2, instead of H3 as previously thought. Although elasticity increases the force required to start nucleating subduction it does not substantially change the total work required to initiate a subduction zone when the yielding stress is small. The analytical model provides an excellent fit to the total work and time to initiate subduction and the force and velocity as a function of convergence and time. Plate convergence and weakening rate during nucleation are the dominant factors influencing the force balance of the plate, and 200 km of plate convergence is typically required to bring a nascent subduction zone into a self-sustaining state. The closed-form solution now provides a framework to better interpret even more complex, time-dependent systems in three dimensions.

Deformation Evolution Law of Surfacing Welding on Thin Bending Plates Based on the Three-Dimensional Thermal Digital Image Correlation Method

Surfacing on the surface of thin metal bending plates will cause significant deformation, and current numerical simulation and experimental methods cannot fully and truly reflect the deformation state of the bending plate. In this paper, a non-contact detection method based on the three-dimensional (3D) thermal digital image correlation (DIC) method is proposed. The proposed method can be used for the 3D full-field dynamic measurement of metal thin bending plate surfaces. In addition, the evolution law of in-plane and out-of-plane deformation of thin bending plates during surfacing welding and cooling was studied. Moreover, the influence of curvature on the shrinkage deformation of thin bending plate weld was explored, and the correlation between the curvature of thin bending plates and the weld shrinkage was established. Results show that the proposed detection method based on the 3D thermal DIC method can rapidly and accurately detect bending deformation online. The out-of-plane deformation of the surfacing welding of the thin bending plate transits from the disk to the saddle. Furthermore, the curvature of the thin bending plate is inversely proportional to the transverse shrinkage of the weld bead. After the curvature reaches a certain value, it has little effect on the longitudinal shrinkage of the weld bead. This detection method solves the problem of welding deformation simulation verification, truly clarifies the law of welding dynamic deformation, and provides a theoretical basis for welding lightweight manufacturing.