Hasil untuk "Materials of engineering and construction. Mechanics of materials"

Shuxin Li, Wenfei Shen, Shuhan Guo et al.

Considered a pivotal advancement for commercial applications, blade coating technology for large area photovoltaic devices has emerged as a forefront research area in the field of polymer solar cells (PSCs). Herein, a high-performance PM6:L8-BO device is fabricated with the blade-coating method in ambient air. Meanwhile, Eu3+-induced diblock polymer aggregates (EIPAs) and Tb3+-induced diblock polymer aggregates (TIPAs) with excellent fluorescent properties were synthesized through self-assembly and incorporated as an additive into the PM6:L8-BO system to increase the ultraviolet light absorption and enhance BC-PSC light harvesting. By employing this strategy, the blade-coating device's power conversion efficiency (PCE) was improved from 12.25 % to 13.63 %, and the relative efficiency was enhanced by 11.3 %. In addition to the performance improvement, the stability of the devices was also enhanced by 19 %, indicating the effectiveness of this approach in producing more efficient and durable PSCs.

Aviad Katiyi, Alina Karabchevsky School of Electrical, Computer Engineering et al.

Optical chips for quantum photonics are cutting-edge technology, merging photonics and quantum mechanics to manipulate light at the quantum level. These chips are crucial for advancing quantum computing, secure communication, and precision sensing by integrating photonic components such as waveguides, beam splitters, and detectors to manipulate single photons, the fundamental carriers of quantum information. Key advancements in optical chips include low-loss waveguides, efficient single-photon sources, and high-fidelity quantum gates, all essential for scalable quantum circuits. Integrating these circuits on a chip offers significant advantages in miniaturization, stability, and reproducibility over traditional bulk optics setups. Recent breakthroughs in materials science and nanofabrication have propelled the field forward, enabling the production of chips with higher precision and lower defect rates. Silicon photonics, in particular, has become a prominent platform due to its compatibility with existing semiconductor manufacturing processes, facilitating the integration of quantum photonic circuits with classical electronic systems. Here, we share our vision of the future of optical chips for quantum photonics, which hold promise for various applications. In quantum computing, they enable the development of compact and scalable quantum processors. In communication, they provide the foundation for ultra-secure quantum networks through quantum key distribution. In sensing, they allow for high-precision measurements that surpass classical limits. As research progresses, optical chips are expected to play a critical role in realizing the full potential of quantum technologies.

Yonatan Kurniawan, Mingjian Wen, E. Tadmor et al.

Machine learning interatomic potentials (MLIPs) enable atomistic simulations with near first-principles accuracy at substantially reduced computational cost, making them powerful tools for large-scale materials modeling. The accuracy of MLIPs is typically validated on a held-out dataset of \emph{ab initio} energies and atomic forces. However, accuracy on these small-scale properties does not guarantee reliability for emergent, system-level behavior -- precisely the regime where atomistic simulations are most needed, but for which direct validation is often computationally prohibitive. As a practical heuristic, predictive precision -- quantified as inverse uncertainty -- is commonly used as a proxy for accuracy, but its reliability remains poorly understood, particularly for system-level predictions. In this work, we systematically assess the relationship between predictive precision and accuracy in both in-distribution (ID) and out-of-distribution (OOD) regimes, focusing on ensemble-based uncertainty quantification methods for neural network potentials, including bootstrap, dropout, random initialization, and snapshot ensembles. We use held-out cross-validation for ID assessment and calculate cold curve energies and phonon dispersion relations for OOD testing. These evaluations are performed across various carbon allotropes as representative test systems. We find that uncertainty estimates can behave counterintuitively in OOD settings, often plateauing or even decreasing as predictive errors grow. These results highlight fundamental limitations of current uncertainty quantification approaches and underscore the need for caution when using predictive precision as a stand-in for accuracy in large-scale, extrapolative applications.

Mathieu Calvat, Chris Bean, Dhruv Anjaria et al.

Abstract To leverage advancements in machine learning for metallic materials design and property prediction, it is crucial to develop a data-reduced representation of metal microstructures that surpasses the limitations of current physics-based discrete microstructure descriptors. This need is particularly relevant for metallic materials processed through additive manufacturing, which exhibit complex hierarchical microstructures that cannot be adequately described using the conventional metrics typically applied to wrought materials. Furthermore, capturing the spatial heterogeneity of microstructures at the different scales is necessary within such framework to accurately predict their properties. To address these challenges, we propose the physical spatial mapping of metal diffraction latent space features. This approach integrates (i) point diffraction data encoding via variational autoencoders or contrastive learning and (ii) the physical mapping of the encoded values. Together, these steps offer a method to comprehensively describe metal microstructures. We demonstrate this approach on a wrought and additively manufactured alloy, showing that it effectively encodes microstructural information and enables direct identification of microstructural heterogeneity not directly possible by physics-based models. This data-reduced microstructure representation opens the application of machine learning models in accelerating metallic material design and accurately predicting their properties.

Euclid Collaboration W. Gillard, T. Maciaszek, E. Prieto et al.

ESA's Euclid cosmology mission relies on the very sensitive and accurately calibrated spectroscopy channel of the Near-Infrared Spectrometer and Photometer (NISP). With three operational grisms in two wavelength intervals, NISP provides diffraction-limited slitless spectroscopy over a field of 0.57,deg^2. A blue grism covers the wavelength range 926--1366,nm at a spectral resolution ( of $440--900$ for a 0 diameter source with a dispersion of 1.24,nm,px^-1. Two red grisms span 1206 to 1892,nm at mathcal R =550--$740$ and a dispersion of 1.37,nm,px^-1. We describe the construction of the grisms as well as the ground testing of the flight model of the NISP instrument, where these properties were established.

Ying Liu, Francesco Di Stasio, Chenghao Bi et al.

Near-Infrared (NIR) light emitting metal halides are emerging as a new generation of optical materials owing to their appealing features, which include low-cost synthesis, solution processability and adjustable optical properties. NIR emitting perovskite-based light-emitting diodes (LEDs) have reached an external quantum efficiency (EQE) over 20% and a device stability of over 10,000 h. Such results have sparked an interest in exploring new NIR metal halide emitters. In this review, we summarize several different types of NIR-emitting metal halides, including lead/tin bromide/iodide perovskites, lanthanide ions doped/based metal halides, double perovskites, low dimensional hybrid and Bi3+/Sb3+/Cr3+ doped metal halides, and assess their recent advancements. The characteristics and mechanisms of narrow-band or broadband NIR luminescence in all these materials are discussed in detail. We also highlight the various applications of NIR-emitting metal halides and provide an outlook for the field.

F. Addesa, T. Anderson, P. Barria et al.

For the High-Luminosity (HL-LHC) phase, the upgrade of the Compact Muon Solenoid (CMS) experiment at CERN will include a novel MIP Timing Detector (MTD). The central part of MTD, the barrel timing layer (BTL), is designed to provide a measurement of the time of arrival of charged particles with a precision of 30 ps at the beginning of HL-LHC, progressively degrading to 60 ps while operating in an extremely harsh radiation environment for over a decade. In this paper we present a comparative analysis of the time resolution of BTL module prototypes made of LYSO:Ce crystal bars read out by silicon photo-multipliers (SiPMs). The timing performance measured in beam test campaigns is presented for prototypes with different construction and operation parameters, such as different SiPM cell sizes (15, 20, 25 and 30 μm), SiPM manufacturers and crystal bar thicknesses. The evolution of time resolution as a function of the irradiation level has been studied using non-irradiated SiPMs as well as SiPMs exposed up to 2 × 1014 neq/cm2 fluence. The key parameters defining the module time resolution such as SiPM characteristics (gain, photon detection efficiency, radiation induced dark count rate) and crystal properties (light output and dimensions) are discussed. These results have informed the final choice of the MTD barrel sensor configuration and offer a unique starting point for the design of future large-area scintillator-based timing detectors in either low or high radiation environments.

Lihui ZHANG, Shuo XIE, Mingfa LUO et al.

Objectives: Bone tissue grinding is one of the common and basic applications in orthopedic surgery clinics. The grinding process is energy-intensive and generates a lot of grinding heat. The accumulation of this heat may cause thermal damage to biological tissues. This paper presents experimental research to investigate the bone-grinding heat and the cooling method. Methods: The combined influence of nozzle position and feed direction on the cooling effect of bone grinding under cryogenic spray cooling conditions is experimentally investigated. A bone grinding platform with three-dimensional motion, as well as a cryogenic spray generation device, is designed and constructed. A spherical diamond grinding head with a diameter of 4 mm and a grit size of #150 is utilized. Fresh bovine cortical bone is used as the processing sample. The temperature at the nozzle outlet is 13 ℃, and the flow rate valve regulates the coolant flow rate to 400 mL/h. A three-dimensional force transducer (DJSW-40, China) is connected to a data acquisition system, which captures the forces applied to the bone sample along the X, Y, and Z directions at a frequency of 100 Hz. Simultaneously, a 0.1 mm diameter type K thermocouple (Omega Inc., TT-K-36) is embedded inside the bone sample to measure the grinding temperature in real-time. Three different nozzle arrangements were designed: above, in front of, and to the side of the abrasive tool, with the nozzles 10 mm away from the spray surface. Six sets of experiments (3×2) were designed using three nozzle orientations and two feeding directions. Each set of experiments was repeated three times to study the cooling effect of the spray under the combined influence of nozzle orientation and feed direction. Results: (1) During bone grinding, the abrasive tool is subjected to three orthogonal directional forces, namely FX (the tangential grinding force used for removing material), FY (the axial grinding force, representing the resistance of the abrasive tool during its feed), and FZ (the normal grinding force, which serves as the support force of the workpiece on the abrasive tool). For forward feed, the average values of the individual forces are: FX = 0.37 N, FY = -0.72 N, FZ = 1.38 N. For backward feed, FX = 0.46 N, FY = 0.78 N, FZ = 1.67 N. Since the grinding tool remains in the same rotational direction, the tangential force FX is consistently positive. For forward/backward feed, the axial force FY is in the -Y and +Y directions respectively, thus the sign of the FY value changes. When feeding forward/backward, the tangential force (FX) is 0.37 N and 0.46 N, respectively, which are relatively similar to each other, in accordance with the grinding theory. The power consumed for grinding is approximately 1.6 W and 1.9 W for forward and backward feed, respectively. (2) The nerve tissue is more heat-sensitive than bone tissue. Taking the human body's 37 ℃ as the base temperature, the threshold for the occurrence of thermal injury is 43 ℃, so the temperature rise threshold for thermal injury of nerve tissue is 6 ℃. In our experiment, the maximum temperature rise of bone under low-temperature spray cooling was lower than 4 ℃, indicating that the cooling method is effective. The effect of the nozzle arrangement was investigated under a fixed forward or backward feeding direction. When the abrasive tool is fed forward, the cooling of the thermocouple under the front nozzle is obvious. This is because, in addition to the contact arc area between the abrasive tool and the bone sample, a portion of the coolant from the front nozzle is sprayed onto the bone sample surface, resulting in a pre-cooling effect within the bone. When the abrasive tool is fed backward, the grinding temperature is lowest when the nozzle is placed above. For the different nozzle orientations, the side nozzles are in a perpendicular plane to the feed direction (Y-direction) of the grinding tool, so the feed direction has the least influence on the grinding temperature. The upper and front nozzles are in the same plane as the feed direction of the abrasive tool, so the influence of the feed direction is more significant. Conclusions: (1) The average tangential grinding force is 0.42 N, axial grinding force is 0.75 N, normal grinding force is 1.53 N, and the average power consumed by grinding is approximately 1.75 W when bone grinding is performed at a depth of 0.5 mm using a spherical diamond abrasive tool with a diameter of 4 mm. (2) Under the cooling effect of the cryogenic spray, the maximum temperature rise of grinding is less than 4 ℃, which can effectively prevent the occurrence of thermal damage in biological tissues. The temperatures of the two thermocouples in the same set of experiments were more consistent when the nozzle was placed above or side, while there was a significant difference in the temperatures of the two thermocouples when the nozzle was placed in front. This indicates that the cooling effect is more uniform when the nozzle is placed above and to the side. (3) The coupling of the nozzle arrangement and the feeding mode has a greater impact on the grinding temperature. When the nozzle is placed on top, it is favorable to backward feeding; when the nozzle is placed in front, it is conducive to forward feeding; and when the nozzle is placed on the side, there is no significant difference in the temperature between forward and backward feeding.

Zhang　Donghai, Pan　Mingxu, Li　Xu, Xu　Yong, Xiong　Hao

The new process of EAF→VOD→LF+VD→ pouring 6 t electrode rod → vacuum consumable remelting （VAR） with lower smelting cost was adopted to produce 15-5PH stainless steel instead of the traditional VIM+VAR process， the causes of point defects were analyzed by scanning electron microscopy and ASPEX detection methods. The results show that calcium aluminate and aluminum spinite exist in the self-consuming electrode， the instability of vacuum consumable remelting process will draw the ingot crown and non-metallic float into the melting pool and remain in the consumable ingot， resulting in point defects after forging.Through process optimization and improvement， the VOD reduction slag is adjusted from 9 kg/t aluminum to 8 kg/t ferrosilicon and 5 kg/t aluminum， the composition of refining slag is adjusted from （mass fraction）CaO 50%-55%， SiO2 10%-15%， Al2O3 20%-25% to CaO 45%-50%， SiO2 5%-10%， Al2O3 33%-38%， vacuum consumable remelting speed is increased from 4.2 kg/min to 6 kg/min， and the melting drop time is increased from 0.23 s to 0.27 s， the cleanliness of consumable electrode has been greatly improved， the melting speed has been controlled steadily， the non-metal floating matter on the liquid surface of the molten pool has been removed， low and high magnification inspection of the finished material have met the standard requirements， and the inspection pass rate has been increased to more than 98%.

Zihan CUI, Bing HAN, Pengcheng WU et al.

Objectives: Femtosecond laser technology has become the primary method for micropore processing due to its high precision and low energy consumption. However, during the process, it is easy to cause microcracks and burrs in the micropores. Additionally, due to the small size, low structural stability and weak wear resistance of the micropores, conventional methods are ineffective in polishing them. To address the challenge of polishing femtosecond laser-processed micropores, the abrasive water jet polishing method is employed. This method leverages the stable removal function and strong adaptability of the abrasive water jet to improve the quality of femtosecond laser-processed micropores. Methods: Computational fluid dynamics (CFD) simulations of the abrasive water jet micropore polishing process under different process parameters were carried out by using Fluent software. A finite element model of abrasive water jet polishing for femtosecond laser-processed micropores was established under various working conditions. The flow field distribution, the erosion rate and the wall shear force under different parameters were analyzed. Corresponding experiments were conducted for each variable discussed in the Fluent simulation, and the variation patterns of micropore inner wall roughness were summarized. Subsequently, optimization experiments were conducted on the three factors, namely jet target distance, jet pressure and abrasive particle size, using the response surface method. The mean square error of shear force on the inner wall of the hole was taken as the response value Y, and the response surface equation was established. The optimal polishing parameter combination was obtained through the response surface equation and experimentally verified. Results: A jet impact angle of 90° is suitable for polishing the inner wall of the micropore, as wall erosion is uniform and the shear force distribution is concentrated at this angle. At a target distance of 4.2 to 6.0 mm, the jet on the end face enters the deceleration stage, and the jet velocity decreases as the target distance increases. The shear force increases with increasing jet pressure. When the jet pressure is 0.80 MPa, the shear force is the smallest, concentrated in the range of 1 500 to 3 500 Pa. At a jet pressure of 1.50 MPa, the shear force is the largest, concentrated in the range of 3 500 to 5 500 Pa. When jet pressure increases from 0.80 to 1.50 MPa, the shear force on the inner wall of the hole increases more than twice. The effects of abrasive particle size and jet pressure on wall shear force are similar. When the abrasive particle size is 1.0 μm, the shear force is the smallest, concentrated in the range of 1 000 to 2 500 Pa. At an abrasive particle size of 30.0 μm, the shear force reaches its maximum, concentrated between 3 000 and 5 500 Pa. Corresponding tests are carried out for each variable discussed in the simulation, and the minimum roughness Ra of the inner wall of the micropore was 0.386 μm. The optimal process parameter combination obtained through response surface analysis is as follows: jet impact angle of 90°, jet target distance of 3.5 mm, jet pressure of 1.10 MPa, and abrasive particle size of 15.0 μm. Under the optimal parameter combination, with an abrasive mass fraction of 5% and a polishing time of 5.0 minutes, the surface roughness Ra of the polished micropore inner wall surface was reduced to 0.354 µm, which is better than the minimum roughness of 0.386 µm observed in the simulation. Polishing efficiency is improved by about 3%, and the quality of the micropore inner wall surface is further enhanced. Conclusions: When the impact angle is constant, the shear force on the inner wall of the hole increases with increasing jet pressure and abrasive particle size. It increases first and then decreases with the increase in jet target distance, with jet pressure having the greatest influence on the wall shear force. Different structural segments of the jet can be applied to different working conditions due to different properties. Additionally, the simulation and experimental results are in good agreement, and the improvement in roughness is significant. This indicates that abrasive water jet polishing significantly enhances the quality of micropore walls, and the data model for response surface prediction has high accuracy.

Hao Cui, Yu-Yue Zhao, Qiong Wu et al.

The clinical application of cancer immunotherapy is unsatisfied due to low response rates and systemic immune-related adverse events. Microwave hyperthermia can be used as a synergistic immunotherapy to amplify the antitumor effect. Herein, we designed a Gd-based metal-organic framework (Gd-MOF) nanosystem for MRI-guided thermotherapy and synergistic immunotherapy, which featured high performance in drug loading and tumor tissue penetration. The PD-1 inhibitor (aPD-1) was initially loaded in the porous Gd-MOF (Gd/M) nanosystem. Then, the phase change material (PCM) and the cancer cell membrane were further sequentially modified on the surface of Gd/MP to obtain Gd-MOF@aPD-1@CM (Gd/MPC). When entering the tumor microenvironment (TME), Gd/MPC induces immunogenic death of tumor cells through microwave thermal responsiveness, improves tumor suppressive immune microenvironment and further enhances anti-tumor ability of T cells by releasing aPD-1. Meanwhile, Gd/MPC can be used for contrast-enhanced MRI. Transcriptomics data revealed that the downregulation of MSK2 in cancer cells leads to the downregulation of c-fos and c-jun, and ultimately leads to the apoptosis of cancer cells after treatment. In general, Gd/MPC nanosystem not only solves the problem of system side effect, but also achieves the controlled drug release via PCM, providing a promising theranostic nanoplatform for development of cancer combination immunotherapy.

Zhenrong Ma, Xia Wang, Tao Wang et al.

Abstract The measurement of phase velocity (PV) in concrete systems is critically important for civil engineers as it provides essential insights into the material properties and structural integrity of concrete. PV, which refers to the speed at which a wave phase propagates through a medium, is directly related to the stiffness and density of the material. By accurately measuring PV, civil engineers can assess the quality and homogeneity of concrete, detect potential flaws, and predict the material’s behavior under various load conditions. This information is crucial for ensuring the safety and durability of concrete structures, from bridges and buildings to pavements and dams. Moreover, understanding PV helps in the optimization of mix designs and the development of new, advanced concrete materials, ultimately leading to more resilient and cost-effective construction practices. For this issue, in this work, for the first time, the measurement of PV in the concrete doubly curved panel reinforced by graphene oxide powders (GOPs) via improved higher-order shear deformation theory is presented. Hamilton’s principle and analytical method are used for extracting and solving the higher-order equations. Finally, some recommendations for improving the efficiency and stability of the concrete structures are presented for related engineering industries. The findings underscore the potential of combining state-of-the-art theoretical models with cutting-edge material reinforcements to push the boundaries of structural engineering and material performance.

V. Yanin, O. Petruchenko

The article updates the most significant information about the outstanding scientist-mechanic and railwayman of the first third of the 20th century Academician of the All-Ukrainian Academy of Sciences Petro Mykhaylovych Suprunenko (1893–1938). It is proven that his activities in the field of railway development are a significant contribution to the development of world science and technology. The main scientific works of the scientist and engineer are devoted to important problems of transport mechanics. He paid special attention to locomotive and wagon construction (he was a wagon designer). Wagons were built on the basis of a large amount of experimental material, which at one time received significant public resonance and scientific and technical recognition. It is emphasized that P. M. Suprunenko was one of the first railway engineers who proposed a scientific analysis of the interaction of the track with the rolling stock of railways. The article notes that today P. M. Suprunenko is mentioned very little, only fragments of his biography are described, only some of his scientific works are characterized. In the Institute of Transport Mechanics of the All-Ukrainian Academy of Sciences headed by him, the following research was successfully developed under his leadership: methodological problems of transport mechanics were highlighted in order to comprehensively solve the tasks of modernization of the railway industry; research of non-stationary dynamic processes of interaction of rolling stock (train) with the track system (especially the study of the resonance phenomenon); research of the theory of calculations of locomotive traction on railway tracks in order to optimize elements of transport mechanics and increase their efficiency, etc. The article describes in detail each of these areas of research by P. M. Suprunenko. In general, his research focused on problems of railway transport. In the field of train traction theory, P. M. Suprunenko created a number of new methods for graphical integration of differential equations of train motion, paid significant attention to improving existing ones and creating new devices designed to measure the characteristics of various processes occurring in rolling stock and tracks. The scientist's achievements in the initial period of railway transport construction in Ukraine, especially on the South-Western Railways, are confirmed. The article shows that the role of P. M. Suprunenko was in his scientific work as an "idea generator" and a leading theorist in combination with engineering activities.

A. Abanda, Odi Thierry, Bahel Benjamin et al.

Pavements are complex structures composed of multiple layers, designed to withstand various types of stress, including mechanical, organic, and climatic. The pavement is constantly subjected to cyclic, dynamic-mechanical actions caused by road traffic and different axle loads. Classified as engineering structures, the standard theoretical durability of this type of construction is generally estimated to be around one hundred years. However, this objective may not be achieved if the designer does not take into account certain specific factors that are endogenous and exogenous to the structure. Therefore, the durability of a road can be achieved through an optimized design that meets the needs defined by the public authorities and the context of its socio-economic framework. This passage discusses the factors that affect the performance of pavements, including soil type, machinery used, users, and climatic conditions. Exceeding axle loads, which form the basis of pavement design calculations, is also a disruptive factor from a civic perspective. A pavement consists of multiple layers, each made up of materials that must meet strict quality criteria and respect the anthropological, economic, social, and natural environment. It is important to consider all of these factors when constructing a pavement to ensure its longevity and avoid any negative impacts on the surrounding area. Additionally, it is crucial to maintain the pavement to prevent any loss of economic or infrastructural development opportunities. Several road infrastructures in urban and inter-urban areas experience issues that result from a combination of causes, each with varying degrees of impact. Douala is one such city where civil engineering projects are subject to an environment that is not conducive to the longevity of infrastructure, especially road infrastructure. The city is situated on a surface layer covered by a predominantly sandy-clay soil. This study aims to propose a proportional mixture of clay and sand soil fractions to create an anvil effect during compaction. The objective is to create a hybrid backfill material that can achieve a high compaction rate. Good compaction is crucial for achieving optimal pavement layer performance. The thickness of the material to be laid is greatly affected by this characteristic, which in turn affects the volume of equipment depreciation and user comfort. This has a significant impact on a wide range of socio-economic benefits. Based on soil mechanics and geotechnical tests, a new material is proposed to combat the early onset of disorders such as potholes, ruts, erosion, or pavement collapse in bad weather or heavy traffic.

S. Abdurasulov, Nuriddin Zayniddinov, A. Yusufov et al.

A. Yusufov, Khamidov Otabek, S. Abdurasulov et al.

Adam M. Krajewski

The true power of computational research typically can lay in either what it accomplishes or what it enables others to accomplish. In this work, both avenues are simultaneously embraced across several distinct efforts existing at three general scales of abstractions of what a material is - atomistic, physical, and design. At each, an efficient materials informatics infrastructure is being built from the ground up based on (1) the fundamental understanding of the underlying prior knowledge, including the data, (2) deployment routes that take advantage of it, and (3) pathways to extend it in an autonomous or semi-autonomous fashion, while heavily relying on artificial intelligence (AI) to guide well-established DFT-based ab initio and CALPHAD-based thermodynamic methods. The resulting multi-level discovery infrastructure is highly generalizable as it focuses on encoding problems to solve them easily rather than looking for an existing solution. To showcase it, this dissertation discusses the design of multi-alloy functionally graded materials (FGMs) incorporating ultra-high temperature refractory high entropy alloys (RHEAs) towards gas turbine and jet engine efficiency increase reducing CO2 emissions, as well as hypersonic vehicles. It leverages a new graph representation of underlying mathematical space using a newly developed algorithm based on combinatorics, not subject to many problems troubling the community. Underneath, property models and phase relations are learned from optimized samplings of the largest and highest quality dataset of HEA in the world, called ULTERA. At the atomistic level, a data ecosystem optimized for machine learning (ML) from over 4.5 million relaxed structures, called MPDD, is used to inform experimental observations and improve thermodynamic models by providing stability data enabled by a new efficient featurization framework.

Prathamesh Satpute, Saurabh Tiwari, Maneet Gupta et al.

There is a significant potential for coding skills to transition fully to natural language in the future. In this context, large language models (LLMs) have shown impressive natural language processing abilities to generate sophisticated computer code for research tasks in various domains. We report the first study on the applicability of LLMs to perform computer experiments on microstructure pattern formation in model materials. In particular, we exploit LLM's ability to generate code for solving various types of phase-field-based partial differential equations (PDEs) that integrate additional physics to model material microstructures. The results indicate that LLMs have a remarkable capacity to generate multi-physics code and can effectively deal with materials microstructure problems up to a certain complexity. However, for complex multi-physics coupled PDEs for which a detailed understanding of the problem is required, LLMs fail to perform the task efficiently, since much more detailed instructions with many iterations of the same query are required to generate the desired output. Nonetheless, at their current stage of development and potential future advancements, LLMs offer a promising outlook for accelerating materials education and research by supporting beginners and experts in their physics-based methodology. We hope this paper will spur further interest to leverage LLMs as a supporting tool in the integrated computational materials engineering (ICME) approach to materials modeling and design.

Nattapat Thawonjak, S. Aimmanee

Abstract Sandwich structures have been a subject of intense scrutiny and utilization in engineering applications. However, there has been a limited understanding of the mechanical behaviors of novel sandwich structures composed of auxetic metamaterials. This study aims to contribute to the body of knowledge by examining the buckling responses of sandwich beams or wide plates with an orthotropic anti-tetra chiral lattice (ATCL) aluminum cores and symmetric angle-ply carbon-fiber/epoxy face sheets, both of which can exhibit highly negative Poisson’s ratios or extreme auxeticity. The linear stability analysis of the sandwich structures under axial compression is conducted by applying the minimum potential energy principle and solving the eigenvalue problem using a numerical method. To achieve an accurate representation of arbitrary two-dimensional buckling morphologies, the first- and fifth-order shear and normal deformation models are employed to simulate the transverse kinematics of the face sheets and cores, while the finite-element model is utilized to discretize the longitudinal displacement of all constituents. The investigation reveals new insights into the interrelationship between global buckling, facial wrinkling, and shear crimping in conventional sandwich structures. The effects of material auxeticity on buckling responses are analyzed across an extensive range of geometrical configurations for the first time, unveiling five unprecedented buckling mode shapes, sophisticated buckling mode landscapes, and Poisson’s ratio-sensitive buckling criteria. These findings lay a crucial foundation for designing and optimizing auxetic sandwich structures, bringing diverse possibilities in lightweight constructions, acoustic insulation, energy absorption, and dynamic and shock mitigation.

E. Tupikova

One of the promising objects for application in architectural and construction practice are analytically determined structural shapes in the form of thin elastic shells with a median surface in the form of algebraic ruled surfaces on a rhombic plan on the basis of various curves. In particular, this study considers three surfaces with identical framework forming lines of superellipses using framework curves that have the appearance of waterline, midships section, and main buttock lines - lines that have been initially generated and used in shipbuilding. The shapes of structures on a rhombic base were considered. The study contains geometric modeling of such structures, creation of finite element models and their computation. A comparison of the values characterizing the stress-strain state for three different shapes with the same span and lifting arm (variant designing with optimized choice) has been carried out. From the theoretical point of view, the possibility of generating three different surfaces on the same frame seems to be an interesting result. From the viewpoint of strength analysis, one of the three obtained shells was chosen as it has the most uniform stress distribution, which is the most economical in terms of material cost.