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Numerous studies have been conducted to minimize material costs and improve efficiency, one of which involves using the genetic algorithm (GA) for material selection. Although the GA provides the best solution, it is computationally intensive. To mitigate this issue, a simple method was proposed. The stiffened plate, a primary component of ship structure, was chosen as the optimization model for this study, with the objective of minimizing material costs using the proposed simple method. Two design variables, plate thickness (t) and plate material type (m), were selected with specific constraints. The simple method was used to determine the appropriate plate material types to reduce material costs. Additionally, size optimization was conducted using stress equations to produce the optimal thickness. The results showed that this method significantly reduced the computational time and material cost of the ship structure.

6063-T4 aluminum alloy plates were friction stir butt and lap welded using three different backing plate materials: mild steel, stainless steel, and asbestos. Effects of backing plate material on macrostructure, peak mid-section temperatures in heat affected and weld nugget zones, and weld mechanical properties were obtained for each of the cases. Effect of backing plate material was seen to be more significant in lap than butt welding. While lap welds obtained even at a low welding speed, for mild steel and stainless steel backing plates, contained multiple weld defects leading to failure in lap shear tests from weld nugget zone, corresponding welds obtained with asbestos backing plate were defect free resulting in failure from base metal region. In butt as well as lap configuration, asbestos backing plate which had the lowest thermal diffusivity was observed to provide the largest process window within which defect free welds could be obtained.

Subduction zones are unique to Earth and fundamental in its evolution, yet we still know little about the causes and mechanisms of their initiation. Numerical models show that far-field forcing may cause subduction initiation at weak pre-existing structures, while inferences from modern subduction zones suggest initiation through spontaneous lithospheric gravitational collapse. For both endmembers, the timing of subduction inception corresponds with initial lower plate burial, whereas coeval or delayed extension in the upper plate are diagnostic of spontaneous or forced subduction initiation, respectively. In modern systems, the earliest extension-related upper plate rocks are found in forearcs, but lower plate rocks that recorded initial burial have been subducted and are inaccessible. Here, we investigate a fossil system, the archetypal Semail Ophiolite of Oman, which exposes both lower and upper plate relics of incipient subduction stages. We show with Lu–Hf and U–Pb geochronology of the lower and upper plate material that initial burial of the lower plate occurred before 104 million years ago, predating upper plate extension and the formation of Semail oceanic crust by at least 8 Myr. Such a time lag reveals far-field forced subduction initiation and provides unequivocal, direct evidence for a subduction initiation mechanism in the geological record.

The requirements for noise control at the boundary of communication substations have been further improved, and it is necessary to meet the Class 2 standard of the Emission Standard for Industrial Enterprise Boundary Environmental Noise (GB12348-2008) . The source control method for the noise of parallel reactors still needs to be further developed. In this context, this paper studies and develops a rubber-based composite damping plate material and completes the noise reduction test of a certain type of parallel reactor with the composite damping plate. The experimental results have verified the effectiveness of this composite damping plate in noise reduction of reactors, with a comprehensive noise reduction of over 8dB (A), providing a new technical solution for noise control of parallel reactors.

The demand for additive manufacturing (AM) of Cu and its alloys shows an increased trend from the energy and heat transfer–related applications. Selective laser melting (SLM) is amongst the key AM processes for metals, providing high geometrical accuracy and design flexibility. The technology is most commonly employed using high-brilliance fibre lasers operating at 1 μm. However, the elevated reflectivity of Cu at this wavelength, combined with its high thermal conductivity, is the cause for a highly unstable process, whereby pore-free products are difficult to obtain. Accordingly, the present work explores the limitations in processing pure Cu powders with a 1-kW single-mode fibre laser providing solutions and different strategies for improving part quality. The process parameters were studied for single and multi-pass melting strategies. The power level requirements, as well as the build plate material, are assessed through an analytical model. The results demonstrate that a correct sequence of multi-pass strategies can improve the part density up to 99.1% ± 0.2% with an industrially acceptable build rate of 12.6 cm 3 /h.

In this study, Mg was alloyed with Zn and Ca to produce six different Mg–Zn–Ca alloys (designated as ZX alloys) by the gravity die casting method. Zn contents of the alloys were 1 wt., 3 wt., and 5 wt.% and Ca contents of the alloys were 0.2 wt. and 1.8 wt.%. Homogenization heat treatment was applied to all cast alloys. After that, a part of each homogenization heat-treated alloys was hot-rolled. Microstructure, mechanical properties, electrochemical and immersion corrosion behaviors at simulated physiological conditions of the heat-treated and hot-rolled alloys were compared. Increasing the amount of alloying elements (Zn and Ca) in Mg reduces grain size and improves the hardness. It was seen that the microstructure consisted of α-Mg as a matrix phase and intermetallic phases: Mg2Ca phase for the alloy having Zn/Ca = 0.37 (ZX12) and Ca2Mg6Zn3 phase for the other alloys. When the mechanical properties and corrosion rates of homogenized and hot-rolled alloys were compared, it was seen that hot-rolled ZX10-h (Mg-0.94Zn-0.16Ca) alloy can be considered as a fracture bone fixation plate material with its acceptable properties: 121 ± 2.1 MPa yield strength, 226 ± 3.7 MPa tensile strength, % 4.1 ± 0.2 elongation, and 0.062 mm/year immersion corrosion rate.

Impact testing is an important means of evaluating an object’s ability to withstand impacts at specific peak accelerations. Currently, commonly used high-g impact testing devices, such as the Mach hammer and air cannon test devices, generally provide overloads ranging from 10, 000g to 30, 000 g, with a maximum of 50, 000 g. To meet the demand for high-overload impact collisions, this paper designs and studies a high-g long pulse width rotary impact test device with a detachable impact head. A finite element simulation model of the impact process was established by using finite element analysis software, and the dynamic response of the device was studied by changing the initial rotation speed and the target plate material. The results show that the overload of this rotary impact test device can reach more than 70, 000 g, and increasing the speed and hardness of the target plate material can improve the overload magnitude. This device and research method can provide theoretical support for high-overload impact testing.

With the rapid development of high - power appliances, the demand for higher power density lithium - ion batteries has soared. Benefitting from its large theoretical capacity and high working voltage, vanadium oxide is considered to be a promising candidate for the next generation of cathode materials for lithium - ion batteries. Among them, orthorhombic V 2 O 5 , with characteristics of easy synthesis and high safety, is prominent and gaining much attention. However, the cycling performance of V 2 O 5 , affected by low electrical conductivity and easy solubility in the electrolyte, is not satisfactory and this has become a stumbling block on the way to its development. This work reports the V 4+  doped V 2 O 5 nanoplate material prepared by the hydrothermal method that has excellent electrochemical properties giving the credit to the increased conductivity and expanded interlayer spacing caused by V 4+ . After doping with V 4+ , the specific capacity of the V - V 2 O 5 electrode is as high as 301.1 mAh g −1 at a current density of 100 mA g −1 , and even more surprisingly, the capacity of the V - V 2 O 5 electrode is still as high as 158.9 mAh g −1 at an ultra-high current density of 4 A g −1 , showing excellent rate performance. This study provides sufficient theoretical support and reference for further exploration of self - doped materials in lithium - ion battery field.

A nonlinear analytical model for the transverse vibration of cracked magneto-electro-elastic (MEE) thin plate is presented using the classical plate theory (CPT). The MEE plate material selected is fiber-reinforced BaTiO 3 – CoFe 2 O 4 composite, which contains a partial crack at the center. The CPT and the simplified line spring model for crack terms are modified to accommodate the effect of electric and magnetic field rigidities. The analysis considers in-plane forces for the MEE plate, which makes the model nonlinear. The derived governing equation is solved by expressing the transverse displacement in terms of modal coordinates. An approximate solution for forced vibration of cracked MEE plate is also obtained using a perturbation technique. The effect of part-through crack, volume fraction of the composite on the vibration frequencies and structure response is investigated. The frequency response curves presented shows the phenomenon of hard or soft spring. Furthermore, the devised model is extended to the case of cracked MEE plate submerged in fluid. Velocity potential function and Bernoulli’s equation are used to incorporate the inertia effect of surrounding fluid. Both partially and totally submerged plate configurations are considered. The validation of the present results is carried out for intact submerged plate as to the best of the author’s knowledge the literature lacks in results for submerged-cracked plates. New results for cracked MEE plate show that the vibration characteristics are affected by volume fraction, crack length, fluid level and depth of immersion.

This study develops a vibration model for functionally graded material (FGM) plates with embedded planar cracks. Based on thin plate theory and von Kármán-type geometric nonlinear strain assumptions, the kinetic and potential energies of each region are derived. Displacement field trial functions are constructed according to boundary conditions, and the Ritz method is employed to determine natural frequencies and vibration modes under small deformation conditions. The investigation focuses on how crack parameters and material gradient coefficients affect vibration characteristics in exponentially graded FGM plates. The results show that natural frequencies decrease with increasing crack length, while crack presence alters nodal line patterns and mode symmetry. During free vibration, the upper and lower surfaces of the crack region exhibit relative displacement. Material gradient effects induce thickness–direction asymmetry, causing non-uniform displacements between the plate’s upper and lower sections.