Front Plate Research Articles

Study on Material Model and Pressure Distribution Characteristics of Off-highway Minning Dump Truck Bucket

In view of the existing problems in the calculation method of the external contour of the material accumulation of the off-highway mining dump truck bucket, the reverse engineering technology and the 3D laser scanning method are proposed to accurately obtain the 3D model of the material distribution in the truck bucket. Based on the three-dimensional solid model of the material, the pressure formulas of the front plate, the side plate and the bottom plate of the bucket are derived by the force analysis method based on the thin-layer element method. References for the structure design and performance analysis of dump truck bucket are provided.

Key performance indicators and leg positioning for the kick-start in competitive swimmers

ABSTRACT The aim of the study was to (1) assess the test–retest reliability of a novel performance analysis system for swimming (KiSwim) including an instrumented starting block and optical motion capture system, (2) identify key performance indicators (KPI) for the kick-start, (3) determine the most beneficial position of the strong leg and (4) investigate the effect of acute reversal of leg positioning. During three sessions, kick-starts of 15 competitive swimmers were investigated. Eighteen kinematic and kinetic parameters showed high reliability (ICC>0.75) from which principal component analysis identified seven KPI (i.e., time to 15 m, time on-block, depth at 7.5 m, horizontal take-off velocity, horizontal impulse back plate, horizontal peak force back plate and vertical peak force front plate). For the preferred start position, the back plate showed a higher horizontal peak force (0.71 vs. 0.96 x body mass; p < 0.001) and impulse (0.191 vs. 0.28Ns/BW; p < 0.001) compared to front plate. Acute reversal of the leg position reduced performance (i.e., increased time to 15 m and reduced horizontal take-off velocity). However, plate-specific kinetic analysis revealed a larger horizontal peak force (p < 0.001) and impulse (p < 0.001) for the back compared to the front plate in any start position investigated. Therefore, swimmers are encouraged to position the strong leg in the back.

Influence of a liquid-filled compartment structure on the incoming shaped charge jet stability

Liquid-filled compartment structure consists of a bulk steel plate with matrix blind holes which are filled with liquid and a steel front plate to seal up the liquid with rings and bolts. The liquid-filled compartment structure can resist the shaped charge warhead effectively. This paper presents experimental and theoretical investigations of the penetration ability of the residual shaped charge jet emerging from the liquid-filled compartment structure after the penetration process at different impact angles. On the basis of shock wave propagation theory, the influence of the liquid-filled compartment structure on jet stability is analysed. The interferences of the liquid backflow caused by a reflected shock wave and a back plate on jet stability under different impact angles are also examined. In addition, the range of the disturbed velocity segments of the jet at different impact angles and the penetration ability of the residual jet are obtained. A theoretical model is validated against the experimental penetration depths.

Pressure drop in large volumetric heat storage tank radial plate diffuser

Abstract In this paper a number of numerical simulations were performed to determine the geometry and the process parameters influence on the large volumetric heat storage tank radial plate diffuser pressure drop. The tank is used in district heating systems. To reduce the possibility of a pressure drop in the diffuser below the water saturation pressure, three basic diffuser types were tested sharpe edge joint (SEJ), conical element (COE) and curved element (CUE). The analysis shows the differences and similarities between the diffuser types and their influence on the static and total diffuser pressure drop. The geometric similarity of the hermetic compressor radial valve with heat storage tank radial plate diffuser was used to validate the numerical model. The numerical calculation results were compared with the experimental measurements of the air pressure drop on the radial valves front plate taken from the literature. Good correlation between the calculation results and experimental measurements has been achieved. Along with mentioned, the diffuser model similarity effect is also presented and analyzed. The obtained results showed that, the static pressure drop remains the same for different diffuser sizes, when the geometric similarity of the diffuser is preserved.

An effective Xe+–Xe interaction potential for electric propulsion systems

An effective Xe+–Xe interaction potential for electric propulsion systems is proposed based on both spin–orbit free interaction potentials and the screened-Coulomb potential. The model not only conforms with the potential obtained by an ab initio method at large internuclear distances but also matches well with the potential derived from experimental scattering data at short internuclear distances. The scattering angles and differential cross sections computed by the effective potential are in good agreement with those obtained by the Morse potential in low-energy regions and those via two screened-Coulomb potentials (the Ziegler–Biersack–Littmark and Zinoviev potential) in high-energy regions, respectively. To further validate the effective potential, a particle-in-cell method with a Monte Carlo collisions technique, coupled with a direct method for solving the scattering equation, was applied to simulate the collisions of 1500-eV and 7000-eV single-charged xenon ions with background xenon atoms in a test cell. The simulated currents on the inner cylinder, exit plate, exit orifice, and front plate are calculated by different potentials. Results show that the effective potential can give a good prediction of the Xe+–Xe elastic collisions in the wider energy region compared with the Morse, Ziegler–Biersack–Littmark, and Zinoviev potentials.

Determining the optimum anatomical coverage of side plates for the VIRTUS body armour and load carriage system

IntroductionSide plates are worn by UK Armed Forces as part of the VIRTUS body armour and load carriage systems to protect the thorax and abdomen from high-velocity threats. The VIRTUS...

Experimental study on flexural behavior of new type of prestressed reactive powder concrete sound barrier for high‐speed rail

AbstractIn this paper, four‐point bending tests of six prestressed reactive powder concrete (RPC) sound barrier unit panels were performed, the flexural behavior, deflection, and failure modes of both in situ and prefabricated panels were studied. The results show that the major failure modes for in situ panels were bending failure. Prestressing the panels can effectively increase the cracking loads and improve the stiffness of the in situ panels, but it cannot improve the ultimate flexural capacities. The ductility of the in situ panels decreased with the increase of prestressing degree. The stiffness of the prefabricated panels was improved by prestressing. Increasing the thickness of back and front plates, the ductility of the panels decreased accordingly, and the ductility of the prefabricated panels decreased more obviously than that of in situ panels. Based on the test results, considering tensile strength of RPC and prestressing stress, a modified formula for flexural capacity of in situ panels was established. In the meantime, considering the “bridge” effect of steel fiber, the formulae to calculate the crack width and deflection at service limit state were also developed for future design.

Phase change heat transfer in a rectangular enclosure as a function of inclination and fin placement

In this paper, melting of a phase change material (PCM) inside a rectangular enclosure, possibly finned and inclined, is studied numerically. The application of this work is related to the temperature control of a finned PV panel filled with PCM and installed at different tilt angles. The studied system is modeled as a 2D rectangular enclosure filled with PCM (RT25) and packed between two aluminum plates, where the front side is exposed to a constant heat flux of 1000 W/m2 for 2 h. Four geometries were considered including a non-finned PCM enclosure, a PCM enclosure with one centered full-width fin, one half-width fin attached to the front plate, and one half-width fin attached to the back plate. Results have shown that the most efficient thermal management of the PV-PCM panel is obtained when the PCM enclosure is equipped with a full-width fin simultaneously attached to the front and back plates. With such a PV panel design, the PCM melting is dominated by natural convection heat transfer from both sides of the PCM enclosure at an early stage, with added heat losses from the back plate to the external environment. Accordingly, low values of the front and back plates temperatures can be maintained during a stabilization time of 80 min as long as the tilt angle is varied from 0° to 75° from the vertical. The efficient temperature control resulting from the full-width fin geometry is mainly related to the high overall heat transfer coefficient obtained during the whole melting process.

The use of new structural solutions of retaining walls to ensure the stable operation of the “base – engineering structure” system

During the design and operation practice, it is necessary to assess the possibility of deformation of structures located on foundations which are able to precipitate and subside. Only with reliable and accurate determination of the stress-strain state of structures of structures together with soil masses during modeling, it is possible to apply the finite element method in practice. The calculations using the PLAXIS and LIRA programs made it easier to analyze the stress-strain state of the soil mass and the stability of retaining walls: I option is corner retaining wall; II option is retaining wall with a structural surface. With the same soil base (layer geometry and physicomechanical properties), loads and boundary load conditions, it is obvious that for the II option the entire mass of soil is included in the work and the stresses are uniformly distributed over the front and foundation plates (over common stresses), uniform structural deformations are observed and soil base, which, in turn, ensures the stability of the retaining wall (according to the general picture of movements) The validity of the theoretical forecast of the behavior of engineering structures interacting with an unevenly deformed base cannot be obtained on the basis of the regulatory framework. This gap can be filled in when modeling the “base – engineering structure” system using modern calculation programs using the finite element method.

Air-blast loading on empty metallic beverage can used as sacrificial cladding: Experimental, analytical and numerical study

The aim of this work is to study the response of a sacrificial cladding using metallic beverage can (MBC) as crushable core. A single MBC axially crushed is considered. An adequate experimental set-up is developed to examine the collapse pattern, the mean crush load and the absorption capacity of a single MBC under a blast load. A comparison with low velocity impact is discussed. The effect of both the entrapped gases inside the MBC and the crush velocity are investigated through analytical and numerical studies. A clear loading rate dependency of the mean crush load is observed. It varies from 0.94 kN to 1.35 kN by increasing the front plate velocity from 17 m/s (FP3) to 44 m/s (FP1). The effect of the entrapped gases inside the MBC structure increases the mean crush load, and, then, the transmitted load to the main structure. In addition to the dynamic material properties, the entrapped gases are considered for an accurate prediction of the mean crush load. Good correlation with the experimental results is observed.

Evaluations of acoustic damping performances of double-layer in-duct perforated plates at low Mach and Helmholtz number.

In this work, acoustic damping performances of double-layer in-duct perforated plates are studied at low Mach (Ma) and Helmholtz number (He) to evaluate the effects of (1) Ma, (2) the porosities (i.e., open-area ratio) σ1 and σ2 of the front and back plates, and (3) the axial distance Lc between these two plates. The orifices' damping is characterized by sound absorption coefficient α denoting the fraction of incident sound energy being absorbed. For this, a quasi-steady acoustic model is developed first and experiments are then conducted. When Ma = 0, α is experimentally found to oscillate with He, whatever the porosities of σ1 and σ2 are set. However, when Ma is increased to and above 0.037, the power absorption troughs, i.e., local αmin of the double-layer plates with σ1,2 ≤ 9% are more separated and shallower. Furthermore, when σ1= 9% or σ2 = 9%, the damping performances are quite different in terms of the local αmax peaks and their number. In addition, increasing Lc with respect to the downstream pipe length Ld gives rise to an increase of αmin and αmax by 10%. Finally, the double-layer plates are shown to involve a larger α than that of single-layer one over a broader He range.

Study on Flow Field and Rotor Safety Characteristics of MSPs Based on Flow Thermo-Coupling

In order to obtain the structural intensity under the operation conditions of MSP (molten salt pump), the rotor component of MSP is taken as the research object. In this paper, the influence of material properties change on the structural performance of MSP at different temperatures is analyzed. The stress distribution and strain distribution of MSP rotor components under different loads are investigated, and the intensity calculation of MSP rotor system is carried out to explore whether it meets the intensity requirements under high temperature operation, which lays a foundation for the high temperature test of MSP. The results show that the maximum deformation position of the blade working face appears at the outer edge of the impeller. When the fluid-structure coupling is applied, the blade strain law and the strain law during thermo-coupling are similar. The effect of the temperature field on the degree of blade deformation is not significant, provided that other factors remain the same. The position where the impeller equivalent stress is the largest is mainly concentrated in the area where the blade is in contact with the front and rear cover plates at the outlet of the impeller. Different degrees of stress concentration occur in the area where the blade is in contact with the impeller hub. The distribution law of the equivalent stress on the surface of the impeller cover plate is that the equivalent stress value changes periodically along the circumferential direction of the impeller, and the number of change cycles is equal to the number of impeller blades. This study can provide a reference for the structural design of MSPs.

Source of organic detritus and bivalve biomass influences nitrogen cycling and extracellular enzyme activity in estuary sediments

In aquatic ecosystems, natural processes that remove nitrogen from the biologically available pool (e.g. denitrification) have been intensively studied as an ecosystem function that reduces eutrophication. The quantity of sediment organic matter is a key driver of denitrification with percent organic content positively related to rates of nitrogen removal; however, few studies have investigated the influence of the quality of organic matter on nitrogen cycling in estuarine sediments despite shifts in primary producers with eutrophication. This laboratory study using intact benthic communities investigates the influence of various organic detritus sources, which vary in their C:N ratio, on nitrogen gas (N2) and solute fluxes and extracellular enzyme activity in estuarine sediments. A custom-built tank with a removable front plate was used with a planar optode film to image sediment oxygenation. Mangrove leaf detritus significantly increased the net N2 production in sediments, while the deposition of other detrital sources and control sediments produced net N2 consumption. Sulfatase activity was significantly reduced in the mangrove leaves and seagrass treatments, suggesting alteration of heterotrophic microbial activity with reducing oxygen conditions. Leucine aminopeptidase activity, indicating nitrogen cycling, was reduced in all treatments, suggesting the organic detritus provided a nitrogen supplement or reduced the activity of extracellular enzymes producing microbes. Bivalve biomass increased net nitrogen gas fluxes in some treatments. Our results indicate different detrital sources may have varying impacts on the removal of bioavailable nitrogen through denitrification and show that feedbacks in biogeochemical cycles may occur with changes in organic detrital source pools.

Experiment and numerical study on dynamic response of liquid cabin under internal blast loading

Abstract Liquid cabin has promising prospects in improving the blast protection of the ship structures under internal blast loading. In this paper, the dynamic response of the liquid cabin was studied through a combination of experimental and numerical methods. First, physical response of the liquid cabin to the internal blast loading was experimentally investigated, and typical deformation modes of liquid cabin plates were obtained. Then, a fluid-solid coupled model was developed to simulate the blast process, and the model was validated by comparing with the data gathered from the tests. Based on that, the pressure characteristics, deformation mechanisms of the front and rear plates and the energy changes of the liquid cabin were numerically analysed. Finally, the influence of the liquid level and the thickness of the liquid cabin on the response characteristics of the liquid cabin was discussed, and the empirical formula was presented.

Influence of sealing gasket distortion on diesel engine injection pump mounting

Currently, the common-rail injection system is composed from a high-pressure pump, injectors, an electronic control unit and a common rail. Over time, the common-rail system has been simplified and optimized, but it remains that the high-pressure pump can still be affected by distortion which occurs during the pump assembly process and in turn has an effect in mounting the pump to the engine. The main assemblies of the diesel pump are the front plate, housing, driveshaft and hydraulic head. Our paper presents a solution for minimizing the distortion and also any external leaks that may occur due to a change in design of the sealing gasket between the body and front plate. This modification realizes the connection interface with the engine block and facilitates the pump mounting. The tests analysis is performed on high pressure pumps to determine where and when the distortion occurs.

Determination of Swarm Front Plate’s Effective Cross Section From Kinetic Simulations

The front plates and embedded particle sensor shells that are part of the electric field instrument (EFI) on the Swarm satellites have recently been used as planar Langmuir probes, as an additional diagnostic tool to infer environment parameters. The interpretation of measured currents in terms of the plasma density or incoming flow speed, however, requires a knowledge of the front plate effective cross section $A_{\textrm {eff}}$ . Measurements made under various space plasma conditions have led to the conclusion that this cross section is generally larger than the known geometrical cross section $A_{\textrm {geo}}$ . Interpretations of measurements have thus been made using fixed relative enhancements of $A_{\textrm {geo}}$ ranging from 8% to 17%. In this paper, results from kinetic simulations are presented, from which the effective cross section can be determined over a range of plasma parameters. These are used to shed light on the physical mechanisms responsible for this enhancement and construct an empirical fit to the relative enhancement $\delta $ , where $A_{\textrm {eff}} = A_{\textrm {geo}}(1 + \delta)$ , and, in turn, enable improvements in the accuracy of inferred plasma parameters.

Numerical analysis of cladding sandwich panels with tubular cores subjected to uniform blast load

This article presents the results of a numerical study on the response of cladding sandwich panels with tubular cores that can be used as blast mitigators. The core of the cladding sandwich panels consisted of empty thin-walled aluminum circular tubes (38 mm in diameter) riveted laterally between the skin plates in different configurations (varying number of tubes and spacing between the tube). The skin of cladding sandwich panels consisted of a “rigid” DOMEX700 steel front plate which was exposed to the blast load and a back plate made of mild steel. The uniform blast load was achieved by detonating varying charge masses of explosive (ranging from 6 g to 50 g) at a stand-off distance of 200 mm down a square mild steel tube. The numerical model, developed in ANSYS AutoDYN 15.0, was validated for average deflection of the front plate and crush mode of the tubular cores using the experimental results that were presented in a previous paper [1]. The results of the simulations provided insights into the transient response of the cladding panels. The effects of the spacing between the tubular cores which also influenced the interaction between the tubular cores were also investigated. The number of plastic hinges formed was increased whilst the rotation angle of plastic hinges decreased with increasing interaction between the tubular cores.

Different Composite Behaviours under Blast Loading

Landmines and Improvised Explosive Devices are known to be major threats for the coalition armies in operation. In order to protect the soldiers from their effects, armored vehicle manufacturers developed some blast protective solutions. However, these solutions often reduce the vehicles’ mobility and payload capacity because of their shape or weight. Fiber Metal Laminates (FML) look like promising light weight blast protective solutions as they associate low areal densities with good bending rigidity and a high number of impedance mismatches which tend to attenuate the shock wave propagation. In this paper, three FML composed of a back plate of armored steel, a middle composite panel named A, B or C and a thin front plate made of mild steel were subjected to a blast loading. The maximum dynamic deformation of each target was recorded during the blast test. A macroscopic post-mortem analysis exhibits three similar behaviors of the back plates but very different permanent deformation patterns of the composite panels. A CT-scan of each panel was then realized to explain these three patterns and, based on these analysis, some hypothesis were made to improve the blast resistance of the B and C panels.

An investigation of ballistic response of reinforced and sandwich concrete panels using computational techniques

Structural performance of nuclear containment structures and power plant facilities is of critical importance for public safety. The performance of concrete in a high-speed hard projectile impact is a complex problem due to a combination of multiple failure modes including brittle tensile fracture, crushing, and spalling. In this study, reinforced concrete (RC) and steel-concrete-steel sandwich (SCSS) panels are investigated under high-speed hard projectile impact. Two modeling techniques, smoothed particle hydrodynamics (SPH) and conventional finite element (FE) analysis with element erosion are used. Penetration depth and global deformation are compared between doubly RC and SCSS panels in order to identify the advantages of the presence of steel plates over the reinforcement layers. A parametric analysis of the front and rear plate thicknesses of the SCSS configuration showed that the SCSS panel with a thick front plate has the best performance in controlling the hard projectile. While a thick rear plate is effective in the case of a large and soft projectile as the plate reduces the rear deformation. The effects of the impact angle and impact velocity are also considered. It was observed that the impact angle for the flat nose missile is critical and the front steel plate is effective in minimizing penetration depth.

Mechanical performance of an improved semi-rigid joint system under bending and axial forces for aluminum single-layer reticulated shells

In this study, the traditional Temcor joint (TR-Temcor) is modified using a central hollow hexagonal prism and some front bolts. The Finite Element Analysis (FEA) model is established and verified by experiments. Then, a parametric analysis is carried out for the improved Temcor joint (IM-Temcor). To obtain the optimal parameters for the modified joint, the key factors, namely: number and location of the front bolts, bolt-hole deviation, pretension force in bolts, thickness of front plate and heat-affected zone caused by the welding work, are considered in the FEA models. The modified joint, with the optimized factors, is analyzed for different static load conditions, considering axial pressure, axial tension, pure bending, bending with axial force, and eccentric axial forces. The overall mechanical behavior of the joint, including the M-Φ curves, initial stiffness, ultimate strength and deformation capacity, as well as the failure modes are identified. The results from the improved joint are compared with corresponding values from of the traditional Temcor joints. The results show that the central hollow hexagonal prism and front bolts significantly improves the stiffness and ultimate strength of the joint, especially when the joint is subjected to pure bending, bending with shear force, axial force, bending with certain axial force and eccentric force.