Plate Area Research Articles

Ballistic response of a high-strength steel

Quasi-static compression/tension, dynamic compression/shear mechanical property tests, fracture morphology characterization, dynamic response experiment, numerical simulation, and calculation of the ultimate penetration velocity of the high-strength steel under the impact of large mass low-velocity fragments and small mass high-velocity fragments were carried out to study the ballistic performance of high-strength steel used for armor vehicle protection and clarify its dynamic response under Ballistic impact. The fracture mode of the high-strength steel under dynamic impact compression and shear was shear failure. A large number of fine parabolic shear dimples were formed on the fracture surface. The high-strength steel had an obvious strain rate strengthening effect and adiabatic shear sensitivity. The plug formed under the low-velocity impact of a large mass fragment was a cone shape, and the impact area of the target plate underwent slight bending plastic deformation. The damage of the fragment to the target plate includes both adiabatic shear failure and ordinary shear failure. Under the high-velocity impact of small mass fragments, the fragments were seriously deformed and destroyed, and the damage model of the target plate is adiabatic shear failure.

2D resistivity model around the rupture area of the 2011 Tohoku-oki earthquake (Mw 9.0)

The 2011 Tohoku-oki earthquake (Mw 9.0) was characterized by a huge fault slip on the shallowest part of the plate interface, where fault behavior had been believed to be aseismic. In this study, we modeled the two-dimensional resistivity distribution across the slip area based on ocean-bottom electromagnetic measurements to understand the physical properties around the plate interface controlling fault rupture processes. The optimal 2D resistivity model showed a conductive area around the shallowest plate interface where the huge coseismic slip was observed, whereas the deeper plate interface where the fault rupture was nucleated was relatively more resistive. The shallowest plate interface was interpreted to have a high pore seawater fraction, whereas the deeper interface was interpreted as a dry area. These findings are consistent with the hypothesis that aseismic frictional conditions changed to conditions enhancing fault rupture when the rupture propagated to the wet, clay-rich shallowest plate area. The optimal resistivity model also revealed a conductive area under the outer-rise area of the Pacific Plate. This finding supports the existence of a hydrated oceanic crust that supplied aqueous water to the subduction zone, including to the huge fault slip area.Graphical

Influences of arbitrary-distributed Kerr foundation on free vibration and nonlinear transient response of functionally graded plate in thermal environment

For the first time, a novel theoretical model is presented for analyzing the effects of the arbitrary-distributed Kerr foundation on the free vibration and transient responses of the functionally graded material (FGM) plate in a thermal environment. According to the power law distribution, the mechanical characteristics of FGM plates are assumed to vary with plate thickness. The three-parameter Kerr model is founded on the independence of the upper and lower elastic layers with respect to the shear layer. The shape and location of the elastic foundation can be determined arbitrarily using mathematical functions. In the area of the FGM plate, the distribution of the elastic foundation is assumed to be either centralized or decentralized. The Reddy’s third-order shear deformation theory is utilized to express the governing equations. Then, the dynamical characteristics of the FGM plate are obtained by using the Galerkin’s method. To validate the accuracy of the current computational model, the achieved results are compared to those derived from published literature. In addition, graphical representations of the effects of stiffness, distributions, and geometrical parameters of elastic foundation, geometrical parameters of plate, material properties, and thermal environment on the vibrational characteristics of the plates are provided.

Электронно-микроскопическое исследование зрительного нерва с токсическим невритом в эксперименте

Рurpose. To identify ultrastructural changes of the optic nerve in the area of the trellis plate in rabbits after exposure to methyl alcohol. Material and methods. A model of experimental optic neuritis with the introduction of methyl alcohol into the retrobulbar space was reproduced on 8 rabbits. The animals were removed from the experiment on the 14th, 30th, 90th and 180th days after the administration of methanol. Pieces of the optic nerve (1–2 mm) were isolated from the enucleated eyeballs in the area of the lattice plate and examined using a transmission electron microscope. Results. On the 14th day after the administration of methanol, signs of pronounced cytoplasmic edema and destruction of intracellular organelles were detected in the ganglion neurons of the rabbit retina in the area of the lattice plate. In individual nerve fibers of the optic nerve, myelin sheaths were stratified and unfolded, axons swelled. Structural changes were detected in astrocytes, especially in the processes around blood vessels. Macrophages of nervous tissue — microgliocytes — became active. Morphological changes indicated a violation of microcirculation and permeability of the hematoneural barrier. The basal membranes around the walls of blood vessels were compacted. Intracellular organelles were destroyed in the cytoplasm of endothelial cells, hemostasis was determined inside the vessels. Subsequently, on the 30–90th day of the experiment, dystrophic and destructive changes in the cytoplasm of ganglion cells and their processes forming the optic nerve, as well as surrounding gliocytes progressed. There were signs of gliofibrosis. Destructive processes and gliofibrosis of the retina and nerve fibers of the optic nerve in the area of the lattice plate increased in degree of expression up to 180th days of the experiment. Conclusion. The results of electron microscopic studies of the intrabulbar part of the optic nerve in experimental animals in dynamics after the introduction of methyl alcohol indicate that the main trigger for the development of visual neuritis may be a violation of microcirculation processes in the retina and optic nerve, which leads to an increase in the permeability of the hematoneural barrier. These events entail dystrophic and destructive changes in the nervous tissue, the progression of which naturally leads, with the assistance of glial cells to gliofibrosis of the optic nerve. Keywords: toxic optic neuritis, methanol, hematoneural barrier, axon demyelination, gliofibrosis

A Self-Growing 3D Porous Sn Protective Layer Enhanced Zn Anode

Aqueous zinc-ion batteries (ZIBs) have received much attention because of their high safety, low pollution, and satisfactory energy density (840 mAh g−1), which is important for the research of new energy storage devices. However, problems such as short cell cycle life and low coulombic efficiency (CE) of zinc (Zn) anodes due to disorderly growth of Zn dendrites and side reactions of hydrogen corrosion have delayed the practical application of ZIBs. In this work, a new “self-growth” method is proposed to build a robust and homogeneous three-dimensional (3D) nanoporous structure of tin (Sn)-coated Zn anodes (ZSN) in just 10 min by a simple and fast reaction, which can largely raise the surface area of the electrode plate. The ZSN not only provides abundant Zn nucleation sites, but also reduces the corrosion current, thus alleviating the self-corrosion of the electrolyte, reducing the occurrence of hydrogen precipitation side reactions, and effectively inhibiting the growth of Zn dendrites during cycling. Thus, a symmetric cell with a ZSN anode can be stabilized with very low voltage hysteresis (30 mV) for 480 h of stable plating/stripping cycles and can operate well for 200 h even at high current densities of 10 mA cm−2. Supercapacitors and button cells were assembled, respectively, to verify the performance of ZSN electrodes in different energy storage tools. The ZSN||AC supercapacitor exhibited superior capacity (75 mAh g−1) and high reversibility (98% coulombic efficiency) at a current density of 2 A g−1. With a MnVO (MVO) electrode as the cathode, the ZSN||MVO full cell presents excellent cycling stability with a capacity retention of 95.4% after 500 cycles at 2 A g−1, which far exceeds that of the bare Zn cell.

Condensation heat transfer of superheated vapour of R1234ze(E) and R134a inside a brazed plate heat exchanger

The recent restrictions on the use of refrigerants with high Global Warming Potential (GWP) have pushed the research to consider alternative solutions, such as the HydroFluoroOlefins, as possible replacements. Even though they are generally mildly flammable, their GWP is significantly lower compared to those of the HydroFluoroCarbons. This paper presents experimental measurements of R1234ze(E) and R134a heat transfer coefficients during condensation inside a brazed plate heat exchanger. Experimental tests during condensation heat transfer have been conducted considering different degrees of superheating, subcooling and outlet vapour quality. The condensation temperature varies between 34.6 °C and 42.3 °C and the refrigerant mass flux is between 9 kg m−2 s−1 and 49 kg m−2 s−1. The results showed that the heat transfer coefficients measured with R134a are between 4% and 8% higher than those of R1234ze(E). Complete condensation experiments showed that an increase in the liquid subcooling degree significantly reduces the thermal performance at low refrigerant mass velocities. In some cases, the plate area occupied by liquid refrigerant reached almost 30% of the overall heat transfer area, thus decreasing by 2.7 times the average heat transfer coefficient when passing from 3 K to 8 K subcooling degree. A comparison with the predictions of some empirical models is also presented to assess which one can better predict the experimental data.

Development of a high-speed small-angle infrared thermography system in EAST.

A high-speed infrared small-angle infrared thermography system (SATS) has been developed and installed on the Experimental Advanced Superconducting Tokamak (EAST) for measuring the surface temperature of the divertor target to calculate the high heat flux induced by Edge Localized Modes (ELMs) and providing observation means for the further physical study of some key parameters, such as power decay length λq and the characteristic time of different types of ELMs. An endoscopic optical system is applied to realize the SATS for clear imaging of the divertor plate area and protection from the harm of impurity deposition and latent tungsten ablation during discharge. The field of view (FOV) of the endoscopic optical system is designed to be 13° in the horizontal direction and 9° in the vertical direction. As a consequence, ∼35° of coverage of the lower-outer divertor and a small part of the lower-inner divertor in toroidal are covered by the FOV with a spatial resolution of around 2 mm/pixel. This paper presents a detailed description of the new SATS and the preliminary experimental diagnostic results. The radial distribution of heat flux induced by an ELM crash was demonstrated.

Thermal-hydraulic performance analysis of a liquid-jet-cooled heat sink with a macroscopic porous flow diverter

In this work, a liquid-jet-cooled heat sink having a microporous flow diverter plate is proposed for the reduction of the maximum operating chip temperature, while simultaneously achieving uniform cooling rates. Different diverter opening ratios (ratio of the macroporous openings to the total diverter plate area) were considered, and the results indicate that the smaller opening ratios create a visible tradeoff between hydraulic and thermal performance. The contrast between thermal and hydraulic performance was assessed using the PPTR overall performance parameter. The heat sinks with smaller opening ratio diverters had better thermal performance and achieved more uniform temperatures than heat sinks with larger opening ratios. The results show that small opening ratio diverters produce higher flow velocities through the nozzles, thus increasing the pressure loss of the heat sinks. The results indicate that heat sinks with small opening ratios yield the lowest thermal resistance at the same pumping power input. In order to eliminate the recirculation zone of the flow chamber, three parametric structures were proposed. The parameterization of the flow chamber eliminated the recirculation regions, but pressure drop reductions of approximately 2.4% to 3.4% were obtained. It was concluded that the recirculation zone of the flow chamber had little effect on pressure drop, while more attention should be put into the openings of the diverter plate.

Investigation of a distillation desalination system driven by solar and ocean thermal energy

Ocean thermal energy is a stable and abundant marine renewable energy that can be adopted for sustainable desalination in remote islands. However, its relatively low available temperature difference restricts its application. Therefore, to manipulate ocean thermal energy while overcoming its unique small thermocline temperature gradient, a dual-energy-driven distillation desalination system driven by solar and ocean thermal energy is put forward. The merits of this system include resolving the nightly failure of solar desalination systems and higher productivity. To quantify the system potential, a numerical model is developed and thermodynamic analysis is conducted. A comparison between dual-energy-driven system and single-energy-driven systems is conducted. The results indicate that the yield can be significantly improved by simultaneously using solar and ocean thermal energy. A single ocean thermal energy-driven desalination can achieve the minimum freshwater productivity of 0.07 kg·h−1, while coupled solar thermal energy can improve freshwater yield to 1.21 kg·h−1, which is 30.1 % higher than that of a single solar desalination. The system power consumption is only 1.77 kW·h/ton. Furthermore, based on the actual meteorological data in Haikou, China, an annual freshwater productivity of 3524 kg (for a 1 m2 absorber plate area) can be obtained, corresponding to a gain output ratio of 0.44.

Reduction of wave load on monopile-supported offshore wind turbine by a gear-type plate

This study investigates the wave diffraction problem of a vertical cylinder with a gear-type plate by using the linear wave theory and the method of eigenfunction expansion. The present model is demonstrated to be accurate, through a comparison with the numerical results of the boundary element method. The horizontal wave force acting on the cylinder can be reduced considerably by the gear-type plate. Meanwhile, the variation in bending moment at the bottom of the cylinder depends on the wave conditions and geometry parameters. A low value of the ratio between water depth and cylinder radius (d/r0) can result in an increase in the bending moment on the cylinder, rather than a decrease, due to the additional loads exerted by the gear-type plate. The bending moment on the cylinder can be reduced significantly by the gear-type plate as d/r0 increases. Within d/r0∈[4,10] of the present monopile-supported wind turbines, the wave loads on the monopile foundation can be reduced significantly by the proposed gear-type plate. Compared with a ring-type plate, a gear-type plate exhibits superior reduction effects over an equal plate area. The loads on the structures are insensitive to the wave exposure angle when the teeth number increases beyond three.

Experimental Study on the Flexural Behavior of Connected Precast Concrete Square Piles

Part of deep foundation pit support engineering needs to select connected precast concrete square piles (CPCSPs). Under the premise that the quality of precast concrete square piles (PCSPs) meets engineering requirements, the quality of CPCSPs becomes the key factor to ensure the safety of foundation pit support structures. This paper puts forward a new connection technology of CPCSPs and carries out the flexural behavior experiment of unconnected precast concrete square piles (UPCSPs) and CPCSPs. The distribution of crack and strain on different surfaces of UPCSPs and CPCSPs are measured by carbon fiber composite strain sense optical cables, glass fiber composite strain sense optical cables, and fixed-point polyurethane strain sense optical cables. The anti-crack load, ultimate load, bending moment, and flexural deformation of UPCSPs and CPCSPs are measured. The experimental results of UPCSPs and CPCSPs are compared. The results show that the anti-crack strength of CPCSPs is greatly increased while the flexural deformation of CPCSPs is decreased before the occurrence of crack. With the development of crack (failure stage), the outside areas of hoop steel plate exhibit cracks. At this moment, the strength of CPCSPs is no longer controlled by the strength of middle areas. The ultimate strength of CPCSPs is basically equivalent to that of UPCSPs. The ultimate bending moment of CPCSPs is higher than its design value (about 66%∼76%). The selection of CPCSPs in the design of foundation pit support has good reliability.

Theoretical calculation method for critical buckling load of locally stiffened U-shaped steel sheet pile using the dynamic coordination coefficient method

In order to solve the problem that U-shaped steel sheet piles (USSSPs) are prone to buckling when inserted, we propose a local stiffened U-shaped steel sheet pile destabilization critical load calculation method, namely ‘dynamic alignment coefficient method’, and analyze the influence of stiffening area, stiffening position and number of stiffening plates on the stiffening effect.The study shows that when the total stiffening area is certain, there is a scheme of stiffening plate arrangement to maximize the critical load value of USSSPs with determined length,and reveals the law of local instability caused by the small width of single stiffening plate when the number of blocks is too large. The critical load value of the member can be increased by 13.55% with the variation of the single stiffener plate arrangement position for 10 m long USSSPs, and the optimized theoretical scheme of stiffener plate arrangement for 10 m and 30 m long USSSPs with different total stiffener area is obtained.

Limits of the Protective Ability of Zinc Coating on Steel

One of the most effective means of protecting metalwork equipment premises from corrosion is currently zinc-plating. Zinc-plating increases the service life of the equipment by 2-3 times, i.e. up to 20 years, which makes this method economically justified.We measured the electrode potentials and corrosion current between two plates – steel and zinc, depending on the size of the zinc plate. Modeling of the corrosion process with a decrease in the zinc coating was carried out by reducing the area of the zinc plate. At the same time, the area of the steel plate was constant. The protective ability of the zinc coating is maintained as long as it occupies at least 10% of the surface area of the steel product. Reducing the area of the zinc coating leads to catastrophic corrosion failure of the coating.

Investigation of the Cold Flow Field in a Flow Reversal Reactor through Computational Fluid Dynamics Models

AbstractTo optimize the flow field in a tubular reactor, new flow deflectors were added by using flow reversal technology. Two optimization structures, namely asterisk plate and composite plate, were designed. Numerical simulation was combined with physical experiments to verify the effectiveness of the flow field optimization. The results showed that the flow field uniformity of the reactor could be greatly improved by single plate and double plate. The uniformity index of the velocity in the axial section is greater than 0.95 within 15 cm, and the physical simulation results conform to the overall trend of the numerical simulation. However, the length of the optimized area of the single plate is about 5 cm shorter than that of the double plate, and it has better stability in the physical model.

Microscopic defects formation and dynamic mechanical response analysis of Q345 steel plate subjected to explosive load

As the basic protective element, steel plate had attracted world-wide attention because of frequent threats of explosive loads. This paper reports the relationships between microscopic defects of Q345 steel plate under the explosive load and its macroscopic dynamics simulation. Firstly, the defect characteristics of the steel plate were investigated by stereoscopic microscope (SM) and scanning electron microscope (SEM). At the macroscopic level, the defect was the formation of cave which was concentrated in the range of 0–3.0 cm from the explosion center, while at the microscopic level, the cavity and void formation were the typical damage characteristics. It also explains that the difference in defect morphology at different positions was the combining results of high temperature and high pressure. Secondly, the variation rules of mechanical properties of steel plate under explosive load were studied. The Arbitrary Lagrange-Euler (ALE) algorithm and multi-material fluid-structure coupling method were used to simulate the explosion process of steel plate. The accuracy of the method was verified by comparing the deformation of the simulation results with the experimental results, the pressure and stress at different positions on the surface of the steel plate were obtained. The simulation results indicated that the critical pressure causing the plate defects may be approximately 2.01 GPa. On this basis, it was found that the variation rules of surface pressure and microscopic defect area of the Q345 steel plate were strikingly similar, and the corresponding mathematical relationship between them was established. Compared with Monomolecular growth fitting models (MGFM) and Logistic fitting models (LFM), the relationship can be better expressed by cubic polynomial fitting model (CPFM). This paper illustrated that the explosive defect characteristics of metal plate at the microscopic level can be explored by analyzing its macroscopic dynamic mechanical response.

Experimental and theoretical study on flexural behavior of steel–concrete composite beams strengthened by CFRP plates with unbonded retrofit systems

In this paper, the flexural behaviors of steel-concrete composite beams strengthened by prestressed carbon fiber-reinforced polymer (CFRP) plate with unbonded retrofit systems were investigated via four-point bending experiments. Three composite beams were strengthened by two groups of CFRP plate with thickness of 2mm or 3mm and prestress level of 10% or 15%, while one un-strengthened composite beam played a role as reference specimen. CFRP plate was transversely stretched by two scissors-type jacks and fixed on the tension flange of steel girder by an independently designed mechanical anchorage system. The experimental results reveal that the application of prestressed CFRP plate efficiently increased the yielding load and ultimate load of steel-concrete composite beams, but the ultimate deflection of mid-span was little affected. The increase of cross-sectional area of CFRP plates contributes more to stiffness of beams than that of prestress level. The CFRP strength utilization ratios of strengthened beams BS-1 and BS-3 at failure are 80%, under the condition of proper anchorage. Moreover, the prestress loss of CFRP plate was monitored for about 100h before test, which was less than 3%. Furthermore, a theoretical model was proposed to calculate the ultimate flexural resistance of strengthened steel-concrete composite beams with unbonded retrofit systems, which was validated with the experimental results.

Performance of small- and wide-angle x-ray scattering beamline at Indus-2 synchrotron

A Small- and Wide-Angle X-ray Scattering (SWAXS) beamline (BL-18) is installed and commissioned at a 1.5 T bending magnet port (5°) of Indus-2 synchrotron at RRCAT, Indore, India. The ∼40-m-long beamline has tunable x-ray energy in the range of 5–20 keV by using a double crystal monochromator. A 1.5-m-long toroidal mirror is used to focus the x-ray beam at the detector position. The beamline is equipped with a 6-m-long movable detector stage to access different wave-vector transfer ranges. At present, an online image plate area detector and a linear position-sensitive gas detector are installed for Small-Angle X-ray Scattering (SAXS) and Wide-Angle X-ray Scattering (WAXS) measurements, respectively. The beamline is operational in simultaneous SAXS/WAXS mode to probe the mesoscopic as well as molecular level structure over a wide range of wave-vector transfer. The specification of the beamline and its performance are reported here. A few recent experimental results, as obtained from BL-18, are also described in brief.

Deep Transfer Learning Approach for Localization of Damage Area in Composite Laminates Using Acoustic Emission Signal

Intelligent composite structures with self-aware functions are preferable for future aircrafts. The real-time location of damaged areas of composites is a key step. In this study, deep transfer learning was used to achieve the real-time location of damaged areas. The sensor network obtained acoustic emission signals from different damaged areas of the aluminum alloy plate. The acoustic emission time-domain signal is transformed into the input image by continuous wavelet transform. The convolutional neural network-based model automatically localized the damaged area by extracting features from the input image. A small amount of composite acoustic emission data was used to fine-tune some network parameters of the basic model through transfer learning. This enabled the model to classify the damaged area of composites. The accuracy of the transfer learning model trained with 900 samples is 96.38%, which is comparable to the accuracy of the model trained directly with 1800 samples; the training time of the former is only 17.68% of that of the latter. The proposed method can be easily adapted to new composite structures using transfer learning and a small dataset, providing a new idea for structural health monitoring.

EVALUATION ANALYSIS OF THE RUNNING SYSTEM SOIL INTERACTION OF WHEELED AGRICULTURAL TRACTORS

The article provides an evaluative analysis of the wheeled agricultural tractor’s running systems soil interaction. A sample of more than 600 MFWD tractors of the world's leading manufacturers was subject to analysis. To determine the parameters of the maximum soil pressure, the value of the footprint gross flat plate area is applied, assuming that the tires are operated under conditions characterized by the speed index A6 with a significant torque for a long time. It is obtained the calculated function of the probability distribution of the maximum pressure on the soil of a sample of modern wheeled tractors with a fixed location of the centre of gravity (weight distribution). The designed arrangement of the centre of gravity of tractors by groups with the corresponding rolling circumference indexes difference ΔRCI =4...9 was analysed. It was established that for general and universal purpose tractors with ΔRCI = 4...6 the most common weight distribution coefficient is 0.40 or 0.44. For special (utility) tractors with ΔRCI = 7...9, the most common weight distribution coefficient is 0.45...0.46. An analysis of the maximum soil pressure in a wide range of the traction force of the tractor while maintaining a constant optimal weight distribution, which depends on the ratio of the footprint gross flat plate area of the front and rear tires, was carried out. The analysis showed that maintaining a constant optimal weight distribution during traction operations makes it possible to reduce the maximum pressure on the soil by 8...40 kPa. This makes it possible to increase the part of the territory of Ukraine, where modern wheeled tractors with single tires can be operated without violating agro-ecological requirements, by 14%.

Study on the phase structure of the interface zone of Cu–Al composite plate in cast-rolling state and different heat treatment temperatures based on EBSD

The phase structure in the interface zone of Cu–Al composite plate was studied by EBSD after casting and rolling and different heat treatment temperatures. The grain sizes of the matrix and intermetallic compounds in the interface zone were analyzed statistically. The spatial distribution characteristics of the transverse, rolled, normal and various phases were characterized by inverse pole diagram. The results show that with the increase of heat treatment temperature, the phase of the interfacial area of the composite plate is rearranged, the residual stress can be released, and the zero resolution decreases. The interface zone of cast-rolled Cu–Al composite plate is composed of a layer of intermetallic compound, which is Al2Cu; Two layers of intermetallic compounds, both Al, were formed in the interfacial area after heat treatment at 300 °C and 400 °C Al2Cu and Al4Cu9;After heat treatment at 450 °C, the interface region is composed of three layers of intermetallic compounds, which is Al2Cu, AlCu, Al4Cu9;The grain size of copper matrix is obviously larger than that of aluminum matrix. Matrix aluminum, matrix copper, Al2Cu.The average grains of Cu are mostly large Angle grain boundaries, and the orientation difference of adjacent grains in aluminum layer is much smaller than that in copper layer. After heat treatment at 300 °C for 1 h, the recrystallization degree of the interface zone of Cu–Al composite plate is low. After heat treatment at 400 °C for 1 h, the recrystallization in the interfacial zone of Cu–Al composite plate is not complete; After annealing at 450 °C for 1 h, the subgrain boundaries in the aluminum layer grow up, and LAGB is basically converted to HAGB. The distribution characteristics of the characteristic appearance direction in the crystal space of each phase were characterized under the conditions of casting and rolling and different heat treatment temperatures. At the same time, the research results provide theoretical basis and scientific title for optimizing the preparation process and high-end application of Cu–Al composite plate.