力学进展

Advances in the investigations and applications of the immersed boundary method

WANG Zhuo, DU Lin, CHENG Long, SUN Xiaofeng

2023, 53(4): 713-739. doi: 10.6052/1000-0992-23-026

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This paper summarizes the advances in the modelling of force source for the immersed boundary (IB) method. Introductions have been given to the applications of this method in the fields of flow around biological structures and fluid-structure interaction, which are representatives of problems with complex and moving geometries, respectively. Although low accuracy at boundary is one main feature of the IB method, it has also been applied to these computational aeroacoustic problems which requires high-order accuracy. Finally, the challenges, advances and future expects of the IB method in dealing with high-Reynolds-number flow are also reviewed.

Research progress in methods and applications of experimental mechanics using micro-Raman spectroscopy

QIU Wei, CHANG Ying, KANG Yilan, XIE Haimei

2023, 53(4): 740-773. doi: 10.6052/1000-0992-23-035

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Micro-Raman spectroscopy (MRS) is a recently developed experimental method for stress analysis. It has the characteristics including high spatial resolution, high testing efficiency and collaborative measurement of multiple physical parameters. It is non-destructive and non-contact, and sensitive to both intrinsic and extrinsic stress, which makes MRS suitable for on-line, in-vito and even living experiments. Moreover, compared with most methods of photomechanics, MRS analyzes stress or strain by a relatively direct way. We illustrate the experimental theories of Raman-stress/strain analyses, and discourse upon several kernel techniques of MRS used in mechanical studies. Then, we summarize the research progress, and finally discuss its development prospects and directions, of MRS in solid mechanics and relative fields. We hope that this review provides a systematic reference for the experimental investigation of micro/nano/multi-scale mechanics using MRS, as well as a rapid and comprehensive understanding for young researchers interested in spectral mechanics.

Research advances in machine learning for structural state identification and condition assessment

HUANG Yong, BAO Yuequan, LI Hui

2023, 53(4): 774-792. doi: 10.6052/1000-0992-23-018

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Structural health monitoring (SHM) has become an important technique to ensure the safety of major engineering structures by sensing, collecting, transmitting and processing multivariate data, through the installation of multiple types of sensors on large engineering structures. With the wide application of SHM system, a huge amount of monitoring data is generated, and how to identify and evaluate the structural condition and safety through monitoring data is one of the core scientific problems. Due to the complexity of civil engineering structures, the core difficulty of state identification and assessment is the optimization and solution of high-dimensional problems. Machine learning has a strong capability in solving high-dimensional problems, providing new ideas for the solution of this problem. This paper focuses on the research progress of machine learning in structural modal identification, damage identification and reliability assessment, and discusses the future development trend in these research directions.

Current status of research on reducing drag and cooling of high-speed aircraft

PAN Lisheng, HAO Henglong, YAO Zikang, GUO Yuan, MU Haofan, LI Min, WEI Xiaolin

2023, 53(4): 793-818. doi: 10.6052/1000-0992-23-021

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Reducing flight resistance and exploring more efficient thermal protection systems are crucial issues in the development of high-speed aircraft. Domestic and foreign scholars have conducted extensive research on the mechanism and application technology of aircraft cooling and drag reduction, and have achieved rich results. This article systematically reviews the research progress in the field of cooling and drag reduction for hypersonic aircraft, elaborates on the research results of active thermal protection mechanisms, introduces cooling and drag reduction technologies applied to high-speed aircraft, And briefly described the development of overall thermal protection systems based on waste heat utilization. Based on the analysis of the current research status, the development trend and practical research needs of drag and heat reduction technology for high-speed aircraft were summarized and summarized. Finally, in response to these practical research needs, some suggestions on research ideas were proposed.

Review of fatigue small cracks in key components of gas turbine engines

ZHAO Gaole, QI Hongyu, LI Shaolin, YANG Xiaoguang, SHI Duoqi

2023, 53(4): 819-865. doi: 10.6052/1000-0992-23-019

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The growth behavior of small cracks, as one of the key stages in the fatigue cracking process, significantly affects the fatigue fracture process of materials and structures. Due to the characteristics of rate fluctuation and expansion path deflection, the small crack effect brings uncertainty to the fatigue life prediction results of materials and structures. It brings uncertainty to the fatigue life prediction results of materials and structures. Therefore, it affects the service safety of mechanical structures such as gas turbines. It focuses on the problem of fatigue small crack propagation in key component materials of gas turbine engines. Firstly, a review was conducted on its laws, and impact on the overall life of materials; Subsequently, the initiation and propagation mechanism of small fatigue cracks is deeply revealed based on polycrystalline and single crystal alloys of advanced gas turbine hot section component materials; Once again, corresponding fatigue small crack growth models were summarized, and the advantages and disadvantages of each model were pointed out; Meanwhile, the fatigue small crack growth behavior and models in hot corrosion/oxidation media are reviewed and discussed combined with the working environment of advanced gas turbine hot section components; Finally, the current research on small cracks was summarized and future research trends were proposed. This review aims to provide theoretical support for the design, safety assessment, and life prediction of key components in advanced gas turbines.

Professor Jia Youquan, the pioneer of experimental mechanics in China

QIU Wei, CHEN Jinlong, LI Linan, KANG Yilan

2023, 53(4): 866-879. doi: 10.6052/1000-0992-23-031

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Professor Jia Youquan is a distinguished mechanist and educator, recognized as the pioneer of experimental mechanics in China. After the establishment of the People's Republic of China, he devoted more than 50 years to mechanical education and scientific research, making outstanding contributions to the establishment and development of experimental mechanics in China. This paper reviewed Professor Jia Youquan's academic career and his patriotic sentiment. His major academic contributions were introduced in three areas: photoelasticity, engineering testing techniques, and photomechanics. Furthermore, this paper summarized his significant accomplishments in foundational education and textbook development of mechanics, outlined his academic ideologies and educational philosophy, and demonstrated several instances of his outstanding accomplishments in closely serving Chinese industrialization construction. Additionally, this paper highlighted his leading role in frontier directions and team developments of experimental mechanics.

2023, 53(4): 880-882.

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2023 Vol. 53, No. 4

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