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Owing to the challenge of capturing the dynamic behaviour of metal experimentally, high-precision numerical simulations have become essential for analysing dynamic characteristics. In this study, calculation accuracy was improved by analysing the impact of constitutive models using the finite element (FE) model, and the deep learning (DL) model was employed for result analysis. The results showed that FE simulations with these models effectively capture the elastic-plastic response, and the ZA model exhibits the highest accuracy, with a 26.0% accuracy improvement compared with other models at 502 m/s for Hugoniot elastic limit (HEL) stress. The different constitutive models offer diverse descriptions of stress during the elastic-plastic response because of temperature effects. Concurrently, the parameters related to the yield strength at quasi-static influence the propagation speed of elastic waves. Calculation show that the yield strength at quasi-static of 6061 Al adheres to y = ax + b for HEL stress. The R-squared (R2) and mean absolute error (MAE) values of the DL model for HEL stress predictions are 0.998 and 0.0062, respectively. This research provides a reference for selecting constitutive models for simulation under the same conditions.

YAG transparent ceramic has great potential in the applications to transparent armour protection modules. To study the dynamic behaviour and obtain the parameters for the equation of state of YAG under the load of longitudinal stress ranging from 0 to 20 GPa, ramp wave and shock compression experiments were conducted based on the electromagnetic loading test platform. The Hugoniot data, isentropic data, dynamic strength, and elastic limit of YAG were obtained. The results showed that the relationship between the longitudinal wave speed and the particle velocity of YAG was linear when the longitudinal stress was lower than the elastic limit. The quasi-isentropic compression and shock Hugoniot compression curves were coincident when the stress in YAG was below 10 GPa; however, a separation of the two curves occurred when the stress in YAG ranged from 10 GPa to the elastic limit. Moreover, the effect of strain rate on the fracture stress of YAG under a moderate strain rate of 10 5 –10 6 s - 1 was more evident than in other strain rate ranges. The amplitude of the precursor wave decayed with increasing sample thickness.

Measurements of the Hugoniot elastic limit and the spall strength of the eutectic alloy Bi—56.5 mass %, Pb—43.5 mass % were carried out at sample temperatures in the range of 20–109°C based on registration and analysis of the evolution of shock compression pulses of various amplitudes. It is shown that an increase in the temperature of the samples leads to a decrease in the Hugoniot elastic limit by 25%, and the spall strength of the alloy under study—by 30%, regardless of the strain rate. An increase in the strain rate by two orders of magnitude leads to an increase in the spall strength by about three times. Approximation power-law dependences of the decay of the elastic precursor on the thickness of the samples and the spall strength on the strain rate before fracture at normal and elevated temperatures are constructed.

The Hugoniot elastic limit and spall strength of reactor Mn2-Si steel under shock compression were measured by recording and subsequent analysis of the wave profiles. The temperature-rate dependences of the resistance to high- strain rate and fracture of steel at normal and elevated temperatures are determined. The results of measurements of the strength characteristics of steel under spall are supplemented by a metallographic analysis of the fracture zone and compared with data for 15Kh2NMFA reactor steel and Armco iron.

At present, the horizontal distance between the surface subsidence boundary and the panel is typically selected as the width of the protection coal pillar with the buried pipeline at the gas–coal integrated mining area (traditional method), which causes abundant coal resources to be unrecoverable. To improve the recovery rate of coal resources, the protective coal pillar of the pipeline is optimally designed. First, the Gaussian function equation of the surface subsidence curve is investigated using the probability integral method (PIM). The elastic deformation limit of the pipeline within the subsidence basin was analysed. Then, the failure probability of the pipeline was calculated by analysing the multifactor indicators that affect it. The elastic deformation limit was modified by considering the time effect of the surface subsidence and the failure probability. Next, by analysing the pipeline deformation in the mining subsidence basins, a novel method for the optimal width of the protective coal pillars with buried pipelines in the thick loose layer undermining is proposed. Meanwhile, the verification method and protection measures for pipeline safety are proposed. Finally, theoretical analysis and engineering examples are used for analysis and verification. The results show that the surface subsidence curve caused by critical mining can be expressed by the Gaussian function when the buried depth/thickness ratio (DTR) of the flat coal seam is greater than 40–60 under thick loose layer. Using Panel 132201 as an example, the prediction method reduced the width of the protected coal pillar by 14 m and increased the panel recovery rate by 3.11% while ensuring the safety of the pipeline. This method effectively promotes coordinated mining between oil–gas and coal resources and provides a reference for the design of pipeline protection coal pillars in gas–coal integrated mining areas. HighlightsA novel method for the optimal width of the protective coal pillars with buried pipelines in the thick loose layer undermining was proposed.Under the premise of considering pipeline safety, this method reduced the width of protective coal pillars and increased the panel recovery rate.The elastic deformation limit was corrected while considering the pipeline failure probability.

Purpose The purpose of this study is to investigate Thermo-mechanical limit elastic speed analysis of functionally graded (FG) rotating disks with the temperature-dependent material properties. Three different material models i.e. power law, sigmoid law and exponential law, along with varying disk profiles, namely, uniform thickness, tapered and exponential disk was considered. Design/methodology/approach The methodology adopted was variational principle wherein the solution was obtained by Galerkin’s error minimization principle. The Young’s modulus, coefficient of thermal expansion and yield stress variation were considered temperature-dependent. Findings The study shows a substantial increase in limit speed as disk profiles change from uniform thickness to exponentially varying thickness. At any radius in a disk, the difference in von Mises stress and yield strength shows the remaining stress-bearing capacity of material at that location. Practical implications Rotating disks are irreplaceable components in machinery and are used widely from power transmission assemblies (for example, gas turbine disks in an aircraft) to energy storage devices. During operations, these structures are mainly subjected to a combination of mechanical and thermal loadings. Originality/value The findings of the present study illustrate the best material models and their grading index, desired for the fabrication of uniform, as well as varying FG disks. Finite element analysis has been performed to validate the present study and good agreement between both the methods is seen.

By recording and analyzing complete wave profiles using the VISAR laser interferometer, measurements of the Hugoniot elastic limit and critical fracture stresses were carried out under the spalling conditions of the heat-resistant Inconel 718 alloy, additively manufactured by direct laser deposition, at shockwave loading up to ~6.5 GPa using a light-gas gun. For comparison, similar experiments were performed with the Inconel 718 alloy made by the traditional method of vacuum induction melting. The process of the delay of an elastic compression wave during its propagation through the sample and the dependence of the spall strength on the strain before fracture in the range 105–106 s−1 were investigated. To identify the anisotropy of the strength properties of the material under study, two series of experiments were carried out on loading additively manufactured samples along and perpendicular to the direction of the deposition. The measurements performed showed that the additively manufactured Inconel 718 alloy demonstrates weak anisotropy of strength properties for both the initial and thermal-treated samples. The thermal treatment leads to a noticeable increase in the Hugoniot elastic limit and the spall strength of the samples at low strain rates. For all types of samples, there is an increase in the spall strength with an increase in the strain rate. The spall strength measured for the cast alloy practically coincides with the strength of the as-received additive alloy and is noticeably lower than the strength of the thermal-treated additive alloy over the entire range of the strain rates. The process of the decay of the elastic precursor in the cast alloy occurs much faster than in the additive one, and the minimum values of the Hugoniot elastic limit are measured for thick samples in the cast alloy.

The present study aimed to provide new insights into the behavior of high-strength low-alloy steel under dynamic compression and to promote its use in high-stress applications. The dynamic compression response of a Cr-Ni-Mo-V steel under shock stresses ranging from 3.54 GPa to 19.76 GPa was investigated using loading technology. The free surface velocity of the specimen was measured using a displacement interferometer system with the range of 166–945 m/s. The Hugoniot elastic limit (HEL), spalling fracture, and microstructure evolution of specimens under different shock stresses were determined. The results showed that an α→ε phase transition occurred in the material at an impact stress of 15.63 GPa, leading to a change in particle velocity. The relationship between the shock wave velocity and particle velocity was found to be linear. The HEL of the steel was found to be consistent at 2.28 GPa, while the spall strength showed a more complex relationship with the increasing shock stress. Initially, the spall strength increased and then decreased with increasing shock stress before increasing again after the phase transformation. The fracture mode of the steel shifted from brittle fracture to ductile fracture with the increasing impact stresses, which is related to the previous plastic deformation under different impact loads.

This study addresses the imperative need for efficient hand-held agricultural tools, particularly in challenging contexts like hillside agriculture, by focusing on the redesign and evaluation of a manual tillage tool. The objective is to comprehensively assess the stress and fatigue life of a redesigned tool, considering different manufacturing materials such as steels (AISI/SAE 4140, 4130, 1060), A356 aluminum, and nodular cast irons. Employing finite element method simulations and the Von Mises equation, this research confirms an optimal performance within elastic limits for all materials, mitigating the risks of plastic deformation or breakage during normal operation, with Von Mises stresses ranging from 8.39 to 16.30 MPa. All the tools yielded optimal results, meeting the critical requirements for soil penetration resistance, reporting no fatigue failures, and exhibiting useful life values over 1.75 x 1013 years. In terms of ergonomics, A356 aluminum stands out, as it is less heavy and implies a lower effort by the operator, promoting efficient tillage without compromising comfort. This research provides nuanced insights for the design of agricultural tools, emphasizing the harmonious balance between efficiency, longevity, and operator comfort in sustainable practices. Este estudio aborda la imperiosa necesidad de herramientas agrícolas manuales que sean eficientes, especialmente en ámbitos desafiantes como la agricultura en laderas, centrándose en el rediseño y evaluación de una herramienta de labranza manual. El objetivo es evaluar exhaustivamente la tensión y la vida útil ante la fatiga de una herramienta rediseñada considerando diferentes materiales de fabricación como aceros (AISI/SAE 4140, 4130, 1060), aluminio A356 y hierros fundidos nodulares. Empleando simulaciones del método de elementos finitos y la ecuación de Von Mises, esta investigación confirma un rendimiento óptimo dentro de los límites elásticos para todos los materiales, mitigando los riesgos de deformación plástica o rotura durante la operación normal, con tensiones de Von Mises que van de 8.39 a 16.30 MPa. Todas las herramientas presentaron resultados óptimos, cumpliendo con los requisitos críticos de resistencia a la penetración del suelo, sin reportar fallas por fatiga y demostrando valores de vida útil superiores a 1.75 x 1013 años. En términos de ergonomía, el aluminio A356 se destaca por ser menos pesado e implicar un menor esfuerzo por parte del operador, promoviendo una labranza eficiente sin comprometer la comodidad. Esta investigación proporciona percepciones matizadas para el diseño de herramientas agrícolas, enfatizando el equilibrio armonioso entre eficiencia, longevidad y comodidad del operador en prácticas sostenibles.

In this work, the critical fracture stresses during spalling of high-strength steel 09CrNi2MoCu samples obtained by direct laser deposition (DLD) were measured under shock compression of up to ~5.5 GPa. The microstructure and mechanical properties of DLD steel samples in the initial state and after heat treatment were studied and compared to traditional hot rolled one. The microstructural features of steel before and after heat treatment were revealed. The heat treatment modes of the deposit specimens on their strength properties under both static and dynamic loads have been investigated. The spall strength of the deposited specimens is somewhat lower than the strength of steel specimens after hot rolling regardless of their heat treatment. The minimum elastic limit of elasticity is exhibited by the deposit specimens. After heat treatment of the deposit samples, the elastic limit increases and approximately doubles. Subsequent heat treatment in the form of hardening and tempering allows obtaining strength properties under Hugoniot loads in traditional hot-rolled products.