Plates Of Different Materials Research Articles

Lamb wave phased array imaging based on phase-amplitude compounding algorithm

Aimed at improving the imaging performance of Lamb wave phased array based on Delay-and-Sum (DAS) of signal amplitude, a compounding imaging algorithm integrating amplitude and phase information of signal is proposed in this paper. By applying back propagation dispersion compensation, the pulse echoes caused by defects will be in-phase with the excitation signal, implementing signal focusing. In the proposed imaging algorithm, the amplitude imaging index is calculated by classical total focusing method (TFM) and the phase imaging index is calculated by phase coherence factor (PCF), which establishes the nonlinear mapping between imaging index and phase difference by sigmoid function with variable gradient. The final imaging results are the compound of two imaging indexes. The experimental validation is carried out on plates of different materials and dimensions with multiple types of defects based on uniform linear array. Compared with the imaging results of conventional TFM, the proposed imaging algorithm can effectively improve the signal-to-noise ratio (SNR) of the images and suppress artifacts, implementing threshold-free imaging.

Bryozoans in fouling communities on artificial substrates in Kazachya bay of the Black Sea

Study of the formation of fouling communities on artificial substrates is actual due to the development of mariculture in the Black Sea. Some representatives of macrofoulers are able to influence the process of colonization and development of cultivated organisms. Purpose of work. The main tasks of the study are the revealing the peculiarities of the formation of the fouling community on the experimental plates of the various materials in the environment of the Kazachya bay in the Black Sea and the role of bryozoans in the fouling community. Materials and methods. The experimental plates which were made from the different materials (plastic, aluminum, rubber, galvanized iron) were installed in September 2017 at a depth of 5 m in Kazachya bay (Black Sea). The plates were lifted every month during the year, a total of 480 plates were examined. Results. The peculiarities of the formation of the fouling community on the experimental plates of different materials in the Kazachya bay (Black Sea) were studied. Totally, 22 species were found in the macrofouling community formed on the experimental plates in the Kazachya bay during the year, comprising the following 8 taxa: hydroid polyps - 1, barnacles - 1, sea anemones - 1, bryozoans - 4, polychaetes - 4, bivalve mollusks - 1, tunicates - 2, macrophytes - 8. During the year, the succession of the fouling community of the experimental plates developed through the stage of dominance of microorganisms - barnacle Amphibalanus improvisus , and then - bryozoan Cryptosula pallasiana. Conclusion: the bryozoan Cryptosula pallasiana is the dominant species in the fouling community at four to twelve months old at a depth of five meters.

Effect of backing plate on mechanical and microstructural properties of tungsten inert gas welded AA 6063 butt joints

In the present scenario, ship building industries are frequently associated with welding process to explore the benefits of improved strength over the parent material. Development of new techniques to enhance the processes is of a part of the usual practice in industries. In the present work, as a supportive measure, backing plate was introduced to develop the weldments with enhanced properties. The central composite design array specimens, a widely used aluminum alloy in marine application AA 6063 were prepared by TIG welding process with the help of backing plates of different materials. Effect of backing plate material on the properties such as ultimate tensile strength and microhardness of the weld joints were investigated. A detailed study of microstructure and macrostructure on the weldment was also done. Results exhibit a considerable improvement for the recommendation of using copper backing plates in the welding processes.

Experimental and numerical investigation on the perforation resistance of double-layered metal shields under high-velocity impact of soft-core projectiles

Multi-layered metal shields have been extensively investigated in the past, mainly studying the effect of layering, spacing and order of plates of different materials. However, at present is not feasible to predict the effect of layering and spacing for a particular case but only general pattern can be considered. Some investigations based on numerical simulations showed that the multi-layered configuration made by layers of different metals could be a promising solution in terms of weight reduction of the shield but, different authors obtained contradictory results and comprehensive experimental investigation is still missing. Thus, the scope of this study is to evaluate the perforation resistance of double-layered metal shields constituted by a high-strength steel and an aluminum layer when impacted by a soft-core projectile. It was found that the multi-layered configuration constituted of two layers of different metals, is less efficient than the monolithic configuration. Furthermore, numerical models were developed to increase the understanding of the problem. It was necessary to use an alternative to the commonly used FE method to model extreme deformation occurring in soft-core projectiles in such kinds of scenario. In particular, the SPH method was implemented providing a detailed parametric study of the most relevant numerical parameters. The SPH method was thus exploited to study different configurations of the double-layer target, and it was found that the specific ballistic energy depends on the ratio between the two layers of the target.

Prediction and Measurement of the Damping Ratios of Laminated Polymer Composite Plates.

Laminated composites materials are mostly used in dynamically loaded structures. The design of these structures with finite element packages is focused on vibrations, elastic deformations and failure control. Damping is often neglected because of its assumed secondary importance and also because of dearth of information on relevant material properties. This trend is prone to change as it is now realised that damping plays an increasingly important role in vibration comfort, noise radiation and crash simulations. This paper shows in a first step how to identify the orthotropic elastic and damping properties of single layer fibre-reinforced composite material sheets using a new extended version of the Resonalyser procedure. The procedure is based on the elastic-viscoelastic correspondence principle and uses a mixed numerical experimental method. In a subsequent step, the complex laminate stiffness values are computed using the identified single layer material properties. To validate this approach, the modal damping ratios of arbitrary laminated plates of different materials at several resonance frequencies are predicted and experimentally verified.

A study on fracture of metal plate under the detonation wave interaction

In this paper, the response of metal plates under the interaction of detonation wave is studied experimentally and numerically. Detonation wave interaction experiments were carried out on metal plates of different materials and thicknesses, and different results such as incision, partial fracture and complete fracture were obtained. ALE algorithm and fluid−solid coupling mode were used to simulate the conditions similar to experiments, and the fracture process and pressure distribution of the metal plate were analyzed. The experimental results were in good agreement with the simulation results. Finally, based on the micro-element fracture theory, the theoretical analysis of the fracture law of the metal plate was carried out, and the fracture criterion based on the threshold impulsive velocity was concluded. It has been verified that this criterion is in good agreement with the simulation and experimental results. It can be used as a basis for estimating the fracture problem of metal plates under explosive load.

Volar PEEK plate for distal radius fracture: analysis of adverse events.

The aim of the present retrospective study was to evaluate complications following carbon-fiber-reinforced polyetheretherketon (CFR-PEEK) volar plating in distal radius fracture in a large cohort of patients. As an alternative to conventional metallic devices, CFR-PEEK plates have been introduced over the last few years. We performed a retrospective study including all patients who were treated for distal radius fracture using a volar fixed-angle plate DiPHOS-RM (Lima Corporate, Udine, Italy). All CFR-PEEK plates implanted were reviewed between May 2012 and December 2017. Plate removal, second surgery and adverse events were collected by reviewing medical records. A total of 110 patients were included with a mean follow-up of 4years. Adverse side effects were observed in 9 cases (8%), developed during or after treatment. The most frequent complication was represented by intraoperative plate rupture (4%). Infection was reported in one case. The rate of complications of PEEK volar plates seems to be similar to those occurring with plates of different materials. Advantages of PEEK plates are the absence of the cold-welding phenomenon and the absence of exuberant bone callus on the plate, ensuring an easy hardware removal. Intraoperative rupture remains the main complication correlated with PEEK material. These complications can be reduced with an accurate surgical technique, especially at the beginning of the learning curve. Therapeutic IV.

Super-achromatic Quarter-wave Phase Retarder for Visible, Near Infrared and Short Wave Infrared Region Applications-=SUP=-*-=/SUP=-

Phase retarders are essential components in optical system design as they can control the phase shifts associated with the vector components of incoming light waves and hence, decide the state of polarization. Different optical systems are designed to work at different wavelength spectrums. Most of these developments focus on the different wavelength regions between visible to infrared, of which the near infrared and short-wave infrared ranges are popular domains for defense and remote sensing applications. In this present communication, a super achromatic quarter-wave phase retarder consisting of four birefringent plates of different materials, i. e. KDP, crystalline quartz, ADP and ZnS has been proposed, to cover the visible, near infrared and short wave infrared regions from 400-2100 nm. As circularly polarized light is less affected by atmospheric conditions the use of an achromatic broadband quarter-wave phase retarder as proposed is quite useful. The proposed system shows acceptable performance over the intended range of wavelengths. Keywords: Wave plates, Super achromatic, Retarder, SWIR.

The influence of the period switching frequency on the heat exchange of a regenerative air heater

A laboratory stand with a regenerative air heater, an automated system for control and measurement of air flow parameters and a nozzle designed to study the heat transfer of a package of parallel plates under non-stationary conditions for different periods are described. The technique of measuring the transient temperature of cold and hot coolant flows taking into account the inertia of thermocouples and the method of measuring the heat transfer coefficient of plates are presented. The time variations of the Nusselt number and the heat power transmitted by the nozzle for individual periods are shown. Values of the average Nusselt number for the period obtained in experiments with the packages of plates of different materials and thicknesses are generalized by a criterial equation convenient for engineering calculations of regenerative air heaters with sheet packing of various types.

INFLUENCE OF THE SWITCHING PERIODS FREQUENCY ON THE THERMAL EMISSIVITY OF A REGENERATIVE AIR PREHEATER

A laboratory stand with a regenerative air preheater, an automated control system and measurement of airflow parameters and a nozzle designed to study the heat transfer of a packet of parallel plates under non-stationary conditions for different periods is described. The technique of measuring the unsteady temperature of cold and hot coolant flows adjusted for inertia of the thermocouples and the method of measuring the heat transfer co efficient of plates. The time variations of the Nusselt number and the heat load transmitted by the nozzle for individual periods are shown. Obtained in experiments with the packages of plates of different materials and thickness values of the average Nusselt number for the period criterial generalized equation for convenient engineering calculations RAPH with leaf nozzles of various types.

A quantitative study on the influence of compressive stress on crack-tip opening displacement

To fill the research gap of estimating crack-tip opening displacement (CTOD) under compressive portion within a cyclic loading, a numerical study is conducted in this paper to quantify the influence of compressive stress on CTOD, and a calculation model of CTOD is established for center-cracked plates under tension-compression loading. The residual CTOD and the variable quantity of CTOD are introduced. Based on a series of finite element analyses, a simple relationship between the variable quantity of CTOD and compressive stress is obtained, which considers the influences of plate width, crack length, stress level (the maximum tensile and compressive stresses) and material property (yield stress, elastic modulus and material hardening). Finally, an example is given and the method in this paper is validated. The proposed calculation model of CTOD has a wide application range and is applicable for finite plates of different materials under tension-compression cyclic loading.

Performance of Monolithic Plate and Layered Plates Under Blast Load

Various critical equipments are used in nuclear, defence and aerospace industries. These equipments which are used in these industries need to be strong and light in weight. Steel, aluminium and magnesium are widely used as structural material in these equipments. With increase in global terrorism it is important that these equipments are safe under blast. Hence, it is imperative to study the behaviour of these plates when subjected to blast loading.Explicit finite element technique using Abaqus@ is used to study the effect of blast load on these plates. Elastic plastic model is used for the materials and Conwep model is used to model the blast load. Numerical simulations are carried out for monolithic plates and layered plates of different materials of equivalent weight. Various combinations of plates for equivalent weight are also studied. The paper discusses the performance of these monolithic and layered plates under blast load.

Response of CMT Welded Aluminum AA5086-H111 to AA6061-T6 Plate with AA4043 Filler for Ballistic

Cold Metal Transfer (CMT) is a proven type of welding method using Metal Inert Gas (MIG). It is a welding technique which can be employed for marine fabrications too. Plates of AA5086-H111 and AA6061-T6 with AA4043 filler is welded by CMT. Parameters like current, voltage, arc length, shield gas pressure etc. are varied to obtain a continuous weld without any crack. Welded thin plates are subjected to a tensile test as per American Welding Society (AWS B4.0:2007) and thereafter impact loads are applied. The plates subjected to impact loads in the range of sub-ordinance level velocities, the feasibility of ordinance and ultra-ordinance can be scaled and compared. Responses and terminal ballistics limit are determined for plate thickness of 1.2mm and 3mm. Present work consists of simulation using Abaqus Software and experiments using Laboratory prepared gun. It was observed that, there was petaling in very thin plates and in some plates it was perforated by plugging for lower ballistic loads and thinner plates. The work gives new insights into the application of CMT in joining plates of different materials with varied thickness values. The material property of plates joined by this welding method was found to be new resource information to the permanent literature of material technology.

Perception of the weight of a falling ball

Among perceived qualities, perceived weight is connected with the feeling of luxury. Many studies of methods for controlling the perception of weight have been reported; most concern visual and haptic effects, but auditory effects have not been considered. This presentation reports analysis of how the perception of weight changes with changes of visual and auditory stimuli in videos in which a falling ball strikes a flat plate. We made 6 balls and 4 plates of different materials with the same size but different weights. We made 24 sets (6 balls × 4 plates) and recorded scenes in which each ball struck each plate. Eleven subjects evaluated the perception of the weight of the ball on a scale of 1 to 7 in all 552 pairs of video comparisons (24 × 23). Scheffe’s paired comparison test revealed that not only visual stimulus but also auditory stimulus can affect the perception of weight.

Improvement of material removal rate of single-crystal diamond by polishing using H2O2 solution

In this study, we investigated the possibility of improving the material removal rate (MRR) of a single-crystal diamond (100) substrate by a polishing technique that utilizes a chemical reaction with H2O2 solution. To demonstrate the feasibility of improving the MRR of the diamond substrate, we investigated the polishing characteristics of the substrate when employing polishing plates of different materials, such as Fe, Cu, Ni, and SUS304, in H2O2 solution. We found that the MRR was highest (33.3nm/h) when using the Ni polishing plate. We also examined the removal characteristics of the diamond substrate in the case of polishing with and without feeding of H2O2 solution to the polishing plate under atmospheric conditions at room temperature. The results showed that polishing with feeding of H2O2 solution to the polishing plate dramatically improved the MRR to 216.7nm/h and also maintained a low surface microroughness of less than 1nm p-v and 0.1nm rms.

On the Cosmical Zero Point Energy Density

The frequency spectrum of the cosmical Zero Point Energy (ZPE) and its total density are so far unknown in their details. In the present complementary investigation, a revised theory forms the basis for studies of this concept in two respects. It first applies to the observable universe considered as an entity, as well as to included subregions such as the galaxies with supermassive black holes. Second, experiments are proposed on the maximum Casimir force arising between two metal plates of different materials and with a vanishing air gap in their spacing. This serves the purpose of making an indirect determination of the ZPE energy density in the laboratory, i.e. at the Earth’s orbit. The ZPE energy density is interpreted as dark matter density and its pressure gradient as dark energy force density.

Biomechanical analysis of acromioclavicular joint dislocation treated with clavicle hook plates in different lengths.

Clavicle hook plates are frequently used in clinical orthopaedics to treat acromioclavicular joint dislocation. However, patients often exhibit acromion osteolysis and per-implant fracture after undergoing hook plate fixation. With the intent of avoiding future complications or fixation failure after clavicle hook plate fixation, we used finite element analysis (FEA) to investigate the biomechanics of clavicle hook plates of different materials and sizes when used in treating acromioclavicular joint dislocation. Using finite element analysis, this study constructed a model comprising four parts: clavicle, acromion, clavicle hook plate and screws, and used the model to simulate implanting different types of clavicle hook plates in patients with acromioclavicular joint dislocation. Then, the biomechanics of stainless steel and titanium alloy clavicle hook plates containing either six or eight screw holes were investigated. The results indicated that using a longer clavicle hook plate decreased the stress value in the clavicle, and mitigated the force that clavicle hook plates exert on the acromion. Using a clavicle hook plate material characterized by a smaller Young's modulus caused a slight increase in the stress on the clavicle. However, the external force the material imposed on the acromion was less than the force exerted on the clavicle. The findings of this study can serve as a reference to help orthopaedic surgeons select clavicle hook plates.

Detonation initiation in shielded thin layers of explosives by shaped-charge jets

The main features of detonation initiation in shielded thin layers of an explosive impacted by high-velocity metal shaped-charge jets are presented. It has been shown experimentally that the exclusion of the initial shock-wave stage of loading of the explosive by shielding the explosive layer by a compressible light material significantly reduces the initiating ability of the shaped-charge jet. The critical conditions of detonation initiation in thin layers of explosives placed between metal plates impacted by shaped-charge jets normally and at an angle of 30° have been experimentally determined; maximum thicknesses of the shielding plates of different materials have been determined above which detonation in the explosive does not occur even upon exposure to the high-velocity head element of a shaped-charge jet.

Analysis of Thermal-Mechanical Coupling of Automotive Disc Brake Based on Numerical Simulation Method

The background and necessity of application of numerical simulation method in research on friction materials of automotive brake are analyzed. The numerical analysis methods of conversion of braking energy, distribution of friction heat, transfer of friction heat and thermal mechanical coupling, are discussed. The dynamic temperature field and thermal stress field of the same brake disc and two kinds of friction plates of different materials, which are the composite materials based on resin and the powder metallurgy based on copper, are simulated and analyzed respectively under emergency braking. The effect of friction materials’ performance on friction temperature and thermal stress distribution is obtained. The results show that the friction performance of composite materials based on resin is better than the powder metallurgy based on copper. The results are consistent with the experimental results. The numerical simulation methods proposed have a good predictive effect on the typical characteristics of friction materials in the process of braking, which provides effective references for preparation and optimization design of friction materials of brake.

Phase equilibrium and mechanisms of crystallization in liquid–liquid phase separating system

The influence of liquid–liquid phase separation (LLPS) in a crystallizing system is examined, and the liquid–liquid tie lines are determined in the ternary system of butyl paraben, water and ethanol. Crystallization by evaporation in droplets (solution of butyl paraben in ethanol and water mixtures) of homogeneous solution and two-phase liquid mixtures on plates of different materials: glass, plastic, steel, and tin were investigated by microscopy. Different crystallization and liquid–liquid phase separation behaviour are observed depending on initial droplet composition and the surface material. This work reveals that crystallization in the LLPS solution of butyl paraben in ethanol–water mixtures starts in the butyl paraben rich phase as can be explained by a higher butyl paraben concentration, and a lower solid–liquid interfacial energy.