Articles in press have been peer-reviewed and accepted, which are not yet assigned to volumes/issues, but are citable by Digital Object Identifier (DOI).
Abstract: The high-temperature gas dynamics was originated from significant changes of macroscopic laws of the gas flows due to physical property changes of the gas mediums when its temperature become extremely high, which goes beyond basic assumptions and research scopes of the gas dynamics. The high-temperature gas dynamics was developed as the core technology for the next generation of aerospace industries is ceaselessly explored when human activities greatly are expanding into the space. This discipline is one of the best models of the engineering science and leads to the development and innovation of the gas dynamics which is pushed forward by the mechanism of application-driven-research. Four dominant research areas of the high-temperature gas dynamics are selected in this paper to conduct a general review with discussions, hoping to help more or less the development of high-temperature gas dynamics. The first area is about hypersonic ground test facilities and measurement technologies. Three typical high-enthalpy shock tunnels were introduced and have been applied to generate the flow velocity of 1.5 - 10 km/s at flight altitudes of 20-100 km. The advanced test facilities are very important for the frontier expansion of disciplines and the discovery of new phenomena in fluid flow physics. The progress in the research area also highlights this truth. The second area is about theories and experiments of hypersonic gas flows, which include their physical and mathematical models, computational methods and results of experimental observations and measurements. Among them, the development of gas physical models is much slower than expected since it is still limited to applications and improvements of the early-developed physical models. The computational method has been developed rapidly, so there are more and more flow phenomena that can be simulated. The progress on the experimental research also is promising due to some large test-model experiments that reproduced model-scaled effects of the hypersonic flow experiments, from which the high-temperature gas physics phenomena revealed is well consistent with hypersonic flight tests. The third one is about supersonic combustion and scramjet engines. This is a research field that has been hot for several decades, during which theoretical and technical researches had achieved a great progress and flight tests have also yielded fruitful results. However, the development of scramjet engines still cannot meet engineering needs and the scramjet engine theory still has difficulties to explain the problems encountered. Therefore, the research of the supersonic combustion and the scramjet engines urgently needs theoretical innovation and technological breakthroughs. The last is about detonation physics and oblique detonation engines. The oblique detonation engine was both almost in the same time with the scramjet engine together, and its research has received a renewed attention only from the beginning of this century. There have been innovative breakthroughs in detonation theory and oblique detonation research since then. And also, a great progress has been made in the standing oblique detonation engine and the hypersonic shock tunnel technology. The oblique detonation engine accepts the unique pressure-gain combustion phenomenon in nature, having the fastest combustion speed, the highest thermal efficiency for its thermal cycle and low heat loads so that it would have a great advantage over others. Finally, the theories, technologies and experiments are summarized about the four research areas of the high-temperature gas dynamics, with which it is expected to provide this discipline with some useful enlightenments.
Jiang Z L. Theory and technology of high-temperature gas dynamics research and applications. AdvancesinMechanics, in press. doi: 10.6052/1000-0992-25-023.
Abstract: In this review, we primarily address the present state of the arts and latest progresses in a few frontier issues mostly relevant to free surface/interface in ocean engineering. They include TC (tropical cyclone) induced extreme surface wave, sloshing of LNG (liquefied natural gas), cavitation/bubble dynamics and VIM (vortex-induced motion) and VIV (vortex-induced vibration). In addition to general description, we mainly focus on the recent advances and challenging aspects of above-mentioned topics. Inspired by the achievements in the previous 70 years, mankind starts a new round of ocean exploration activities. Then, we can find obvious trends: the realm of ocean engineering is expanding from sea surface to deep sea, from low and middle latitude to polar region and from fossil to renewable energy in near future.
Li J C, Nie B C, Lin H H trans. A few frontier issues in ocean engineering mechanics. AdvancesinMechanics, in press. doi: 10.6052/1000-0992-25-044.
Abstract: Microgravity science is one of the cornerstones of space science and applications. It represents an emerging focal point in the global science and technology arena and stands as a significant hallmark of national competitiveness in space technology. With the completion of China’s space station and the impending retirement of the International Space Station, China’s space station—serving as a national space laboratory—will solicit and carry out over a thousand scientific research projects during its operational lifetime, providing a unique experimental platform and offering unprecedented opportunities for the development of microgravity science in China. Based on the 385th “Shuangqing Forum” of the National Natural Science Foundation of China (NSFC), this paper summarizes the challenges and difficulties faced by China’s microgravity science and technology research. It reviews the major progress and achievements made in recent years in fields of microgravity fluid physics, microgravity manufacturing and space technology, and microgravity life sciences and biomedical engineering technology. Furthermore, the article identifies the critical scientific issues facing the field of microgravity science and technology in the coming 5 to 10 years, and discusses frontier research directions and suggestions for the development of the discipline.
He G W, Zhou J P, Zhang W H, Gu Y D, Zhang P F, Chen M, Kang Q, Long M, Tian Q, Zhang L, Ba J, Zhu J H, Wang L Z, Lyu S Q, Li Z B. Microgravity science: The new horizon for knowledge expansion and transformative technologies. AdvancesinMechanics, in press. doi: 10.6052/1000-0992-25-043.
Abstract: Amorphous alloys exhibit complex viscoelastic behaviors due to their unique atomic structure, characterized by dynamic relaxation and static hysteresis features. This not only serves as a core entry point for in-depth understanding of fundamental physical issues such as glass transition, plastic deformation mechanisms, and dynamic heterogeneity, but also provides key theoretical support for the development and engineering application of high-performance amorphous alloys. Currently, how to construct a theoretical framework from the microscopic mechanism that can uniformly describe and predict their complex viscoelastic behaviors remains a core challenge in this field. This paper focuses on the core role and latest progress of the quasi-point defect (QPD) theory in systematically analyzing the viscoelastic behaviors. It deeply explores the application of the QPD theory in analyzing dynamic relaxation and reveals the intrinsic consistency between this theory and fractional models. On this basis, it reviews the intrinsic connection between dynamic relaxation and macroscopic quasi-static viscoelastic deformation, and explains the physical mechanisms behind phenomena such as two-step relaxation and creep, which are dominated by defect movements at different scales. Regarding creep behavior, it particularly discusses the understanding of defect evolution and multi-level power-law creep mechanisms. Additionally, this paper systematically expounds the mechanism of regulating the energy state of amorphous alloys through viscoelastic deformation and how this regulation changes the dynamic relaxation of the material by influencing the concentration, distribution, and cooperative movement of quasi-point defects. This paper aims to demonstrate how to establish the correlation between the microstructure heterogeneity, defect dynamics, and viscoelastic response of amorphous alloys based on the QPD theory, providing a theoretical perspective for understanding and predicting their complex mechanical behaviors.
Qiao J C, Zhang L T, Xing G H, Hao Q, Liang S Y, Cui J B, Duan Y J. Viscoelastic behaviors of amorphous alloys in the framework of the quasi-point defect theory. AdvancesinMechanics, in press. doi: 10.6052/1000-0992-25-015.
Abstract: Thin-walled structures are commonly found in aircraft. As advanced aircraft evolve to meet the demands of wide speed ranges, transmedium capabilities, and large sizes, the vibro-acoustic environments of thin-walled structures have become increasingly complex. Consequently, there is a pressing need for low-frequency, wide-band and time-varying vibro-acoustic control. The rapid advancement of metastructures/metamaterials has opened new opportunities for breakthroughs in air-vehicle technologies. Thin-walled metastructures based on the local-resonance mechanism offer significant advantages in addressing the challenges of vibro-acoustic control of aircraft. This paper reviews the progress of passive and piezoelectric thin-walled metastructures, focusing on their vibration suppression and sound insulation capabilities, and provides a comparative analysis of their evolutionary process and technical features. It offers guidelines for designing thin-walled metastructures in advanced aircraft. First, the mechanisms of local-resonance bandgaps in both passive and piezoelectric thin-walled metastructures are explained, along with their sound-insulation mechanisms, which lays the theoretical foundation for introducing research progress of this area. Additionally, the research progress of thin-walled metastructures for vibration suppression and sound insulation is reviewed, with particular attention to nonlinear thin-walled metastructures. Subsequently, the applications of thin-walled metastructures in addressing vibro-acoustic control issues of air vehicles are discussed. Last, this paper offers future outlooks for thin-walled metastructures in air vehicles, focusing on optimal design, intelligent tuning, multifunctional integration, adaptability to extreme environments and precision manufacturing.
Zheng Y S, Yuan H B, Qu Y G, Meng G. Advances in thin-walled metastructures for vibration and noise control and their applications in aerospace engineering. AdvancesinMechanics, in press. doi: 10.6052/1000-0992-25-024.
Abstract: The rapid advancement of machine learning is transforming the research paradigm of mechanical properties of metallic materials from experience-driven to data-driven. This review systematically summarizes recent progress and challenges in machine learning based prediction of mechanical properties in metallic materials. We first outline commonly used ML algorithms and workflows, with an emphasis on cutting-edge methods such as explainable AI and physics-informed machine learning. We then review typical applications and predictive performance of ML models across three scales: micro/mesoscopic properties (e.g., microstructural evolution, fracture behavior), macroscopic properties (e.g., hardness, stress response, fatigue life), and cross-scale coupling properties (e.g., flow stress, yield strength, constitutive parameter inversion), highlighting their advantages in high-throughput computation and multi-scale modeling. Finally, we identify persistent challenges such as data scarcity, heterogeneity, and insufficient accuracy under wide temperature/strain-rate ranges, and propose potential solutions including transfer learning, large language models, and multi-modal fusion. Looking forward, we outline a technical pathway integrating multi-modal data and physical mechanisms for accurate prediction of mechanical behavior under extreme conditions, aiming to advance materials mechanics toward digitalization and intelligence.
Cao Z Z, Wang G J, Luo B Q. Intelligent prediction of mechanical properties in metallic materials based on machine learning: A review & perspective. AdvancesinMechanics, in press. doi: 10.6052/1000-0992-25-026.
Abstract: The construction background of three full scale low speed wind tunnels in the United States and Russia is briefly introduced. Then, emphasis on tests performed in these wind tunnels are presented, including test operation mode, test model types, test technologies, etc, especially for special test techniques of the full scale wind tunnel. The future development trend of the test techniques is concluded. Research results show that the construction need of full scale wind tunnel is mainly originated from large model aerodynamic test and some related technology development. During model test process, more special attentions are paid to the installation of very large model and the treatment of test failure. The models tested in full scale wind tunnel mainly include airplanes, aerospace vehicles, and energy infrastructures. Additionally, fundamental aerodynamic problem such as rotor flow, acoustic noise can also be resolved in such kind of wind tunnel. As far as the test technique is concerned, conventional measurement method such as force balance, pressure transducer and hot wire anemometer can be used. More importantly, special test techniques developed for full scale model tilting test apparatus, test benches with very large angle of attack, model free flight mechanism, non-intrusive optical measurement and bad weather simulation facility are also been described. The general development trend of test technique is obtained, including going along a direction of providing data with high precision, combining and utilizing various test methods, enabling development with big data in depth, integrating multidiscipline research, developing virtual and augmented reality, etc. Finally, some enlightenments and suggestions are put forward, such as developing test techniques step by step, building professional experimental stand, and highlighting the advantages of large scale and detailed measurements.
Liu X B, Guo C W, Li W J, Chen L J, Zhang J L, Duan Y T. A review of construction and test operation for full scale low speed wind tunnels overseas. AdvancesinMechanics, in press. doi: 10.6052/1000-0992-25-025.
Abstract: The interactions of coaxial vortex rings are the typical flow in subsonic jets and the significant sources of jet noise. Controlling the acceleration and deceleration of vortex rings during the interactions is critical to noise reduction. Previous studies have shown that the radial acceleration of the weaker ring is the dominant contributor to high-amplitude, low-frequency noise. In this work, the conditions under which this phenomenon occurs and the physical laws that govern it are investigated based on Dyson thin-core vortex ring model. By decomposing the acoustic source into the product of the vortex rings’ axial and radial kinematic parameters, the interactions of vortex rings are analyzed under various initial circulation and radius ratios. A critical initial radius ratio is identified, below which the source term related to the radial acceleration of the weaker ring contributes more to the total noise source than that of the stronger ring. Through quantitative analysis of the vortex ring interaction dynamics, the correlation between the peak value of the noise pulse and the peak values of axial velocity and radial acceleration of the rings is established. Moreover, the reverse motion of the stronger ring can induce an out-of-phase pulse in its corresponding acoustic source term.
Zang Z Y, Zhou Z T, Wang S Z. Investigation of noise generated by the interactions of coaxial vortex rings. AdvancesinMechanics, in press. doi: 10.6052/1000-0992-25-020.
Abstract: Understanding the relationships between material microstructures and their mechanical performance and using them to make predictions are pivotal topics in solid mechanics. From Galileo’s beam bending analysis, Cauchy’s stress definition to Arrhenius-based creep laws, theoretical and simulation frameworks find great success in addressing engineering problems. Yet, the spatiotemporal complexity challenges the conventional ‘observation-hypothesis-model’ approach for structural integrity in key industrial sectors such as aerospace, nuclear energy, and semiconductors. Recent progress and fusion of high-performance computing, high-throughput experiments, data science, and artificial intelligence provide a complementary solution to scientific discovery and engineering deployment on these issues. However, unlike their applications in vision and language domains, engineering science demands stronger data-model inference capabilities. High-quality, physically consistent databases and digital libraries are needed to enhance model performance, generalization, and interpretability. Concepts such as “physics transfer” and “reality reconstruction” offer guiding principles for modeling and predicting complex behaviors. With further support from cognitive science, intelligent agents and physical intelligence are increasingly capable of assisting, or even replacing, researchers in conducting exploration and reasoning in complex, dynamic scenarios. This paper reviews key insights of the complexities in solid mechanics and discusses active research areas through the lenses of learning theory and open science, with particular emphasis on multiscale mechanics and the long-term service behavior of materials and structures.
Xu Z P. Resolving physical complexities with machine intelligence. AdvancesinMechanics, in press. doi: 10.6052/1000-0992-25-018.
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