Special issue

1 Review of the technological development of high-end force measuring instruments

QIN Haifeng , ZHANG Yizhi , CHEN Wei , LIU Sibo

2026, 46(3):30-41. DOI: 10.11823/j.issn.1674-5795.2026.03.05

[Abstract](51) [HTML](38) [PDF 9.36 M](70)

Abstract:
This paper introduces the development trajectory of force measurement technology, as well as the working principles, technical characteristics and applications of traditional force measurement technologies, including mechanical, hydraulic, resistance strain gauge and piezoelectric methods, and emerging techniques such as fiber-optic, electromagnetic, and quantum force measurement. It expounds the development directions of the high-end force measuring instruments in terms of high precision, extreme force value, multi-dimension, high dynamic performance, intellectualization and engineering application against the background of rapid upgrading of strategic emerging industries such as aerospace and high-end equipment manufacturing. It analyzes the research progress of current high-end force measurement technology in various directions, and discusses the development status and construction ideas of the force value traceability system, as well as the technical status and core difficulties of static / dynamic force calibration, multi-component force calibration and uncertainty evaluation. It points out that traditional force measurement technologies still need to be improved in terms of accuracy, measurement range and environmental adaptability. The future development is outlined, proposing the need for innovation in new materials and processes, interdisciplinary collaboration, and deep integration with such emerging techniques as internet of things, big data, and artificial intelligence to drive the industrialization of high-end force measurement instruments and provide technology support for national high-quality manufacturing development.

2 Digital online Brinell hardness testing method for complex components

SHI Wei , CHEN Shilin , MENG Wei , RAO Zheyu , NIE Jing , FANG Huachun

2026, 46(2):147-154. DOI: 10.11823/j.issn.1674-5795.2026.02.13

[Abstract](58) [HTML](68) [PDF 3.97 M](58)

Abstract:
To address the inherent limitations of traditional laboratory hardness testing methods, such as random sampling, result latency, and data silos, this paper proposes a digital online Brinell hardness testing method tailored for complex components, exemplified by aero-engine blades. The proposed method overcomes critical technical bottlenecks, including the precise positioning of irregular workpieces under dynamic conditions, adaptive constant-force surface grinding, and the high-precision recognition of low-quality indentation images in industrial environments. Consequently, a digital online testing production line was established, enabling accurate hardness measurement, real-time result evaluation, and full data traceability. Experimental results demonstrate that compared to traditional methods, the proposed approach increases measurement efficiency by a factor of four. Furthermore, the Measurement Systems Analysis (MSA) yielded a Gauge Repeatability and Reproducibility percentage (GR&R%) of 17.42%, with long-term operational performance consistently meeting requirements. By facilitating in-situ, real-time, fully automated, and traceable hardness measurement, this method provides a viable technical pathway for achieving the "integration of metrology and testing" within the context of intelligent manufacturing.

3 Research on hybrid GRR method of automatic hardness testing system based on process decoupling

MENG Wei , SHI Wei , CHEN Shilin

2025, 45(6):116-127. DOI: 10.11823/j.issn.1674-5795.2025.06.10

[Abstract](247) [HTML](138) [PDF 2.80 M](267)

Abstract:
To systematically solve the application problems of Measurement System Analysis (MSA) in the automatic hardness detection system, the particularity of its MSA is expounded, and points out the limitations of the traditional Gauge Repeatability and Reproducibility (GRR) method in the identification of variation sources and experimental design. On this basis, a "process decoupling hybrid GRR" experimental strategy is proposed, which decouples the hardness testing process into two sub processes: indentation generation (destructive) and indentation measurement (non-destructive). Nested design and cross design are used to separate and quantify the variation sources, respectively. Through the construction of an automation platform with double detection units, the systematic MSA experiment was conducted, and the analysis of variance was used to evaluate the influence of equipment repeatability, reproducibility and interaction. The results show that the proposed method can effectively identify the dominant variation sources, and provide a feasible analysis framework for the performance evaluation and optimization of the automatic hardness testing system, which has strong engineering applicability and popularization value.

4 Dynamic measurement of Young's modulus based on multi-order resonance of metallic materials

LIU Fule , ZU Hongfei , CHEN Zhangwei

2025, 45(4):149-157. DOI: 10.11823/j.issn.1674-5795.2025.04.11

[Abstract](248) [HTML](190) [PDF 3.76 M](325)

Abstract:
To accurately analyze the functional characteristics of metallic materials and test their structural stability, based on the Euler-Bernoulli beam theory, a multi-order resonance method is proposed to calculate the dynamic Young's modulus by analyzing the first-and second-order resonant frequencies of the material; and a dynamic test system with a high-frequency exciter and a laser vibrometer as the core is built. The system has a wide dynamic range, precise control and measurement capabilities, and excellent anti-interference. Four kinds of metal materials were tested, and their average values and coefficients of variation of Young's modulus were calculated, statistically analyzed. It is verified that the method has high accuracy, consistency and robustness, while effectively avoiding the influence of strain measurement tools and internal structure changes in traditional static tests. This study provides important support for the development of performance testing and structural analysis of isotropic metals and non-metallic materials.

5 OCR system for pressure instruments based on convolutional neural network

WANG Jingxing , CHEN Shilin , LI Yiming , WANG Li , SHI Wei , LIU Fang

2025, 45(3):111-122. DOI: 10.11823/j.issn.1674-5795.2025.03.10

[Abstract](449) [HTML](162) [PDF 6.33 M](733)

Abstract:
To address the inefficiency, error-proneness, and safety risks associated with traditional manual meter reading for pressure instruments, as well as the limited adaptability of automated meter-reading technologies based on sensors and 3D vision, this study integrates computer vision and artificial intelligence technologies to develop a metering system that combines data acquisition, real-time monitoring, and data analysis. By improving the fast region-convolutional neural network（Fast R-CNN) algorithm through data augmentation and a lightweight feature extraction network, the system optimizes instrument positioning accuracy in complex environments. Additionally, the DeepLabv3+ model is enhanced by incorporating channel attention and spatial attention mechanisms, along with a hybrid loss function, to improve character segmentation efficiency. Experimental results demonstrate that the improved algorithm achieves an average positioning accuracy of 84% for instrument dial positioning and a mean Intersection over union of 78.6% for character segmentation in challenging industrial environments. Furthermore, the system reduces the time required for a single measurement by 85% compared to manual reading, confirming its high efficiency and strong adaptability. This research provides a scalable technical framework for intelligent monitoring of industrial equipment, offering the practical value for advancing digital and intelligent metering.

6 Study on the dynamic characteristics of pressure pipeline under gas-liquid mixing conditions

SHI Bo , CHEN Xiaosong , LI Feng

2025, 45(1). DOI: 10.11823/j.issn.1674-5795.2025.01.08

[Abstract](483) [HTML](147) [PDF 2.47 M](535)

Abstract:
When using pressure pipeline for measuring high-temperature pulsating pressure in aircraft engines, high-temperature condensed water may cause a state of "gas mixed with liquid" in the pressure pipeline, and using traditional dynamic models of gas medium pressure pipeline for analysis may result in significant errors. In response to this issue, a transfer function of the pressure pipeline under the condition of "gas mixed with liquid" was established based on a compressible fluid pressure pipeline system model. Pressure pipelines of the same length but different inner diameters were selected, and experimental research was conducted under different gas-liquid mixing states by adjusting pressure and gas-liquid ratio. The relationship between the dynamic characteristics of the pressure pipeline and gas-liquid ratio was obtained, and the differentiated features of the dynamic characteristics of the pressure pipeline after gas-liquid mixing under different pipe diameters were obtained. This lays the foundation for the subsequent research on the dynamic characteristics of the pressure pipeline under other complex medium conditions, and provides technical reference for improving the accuracy of dynamic pressure testing of aviation engines.

7 Fabrication and performance study of thin-film strain gauges for strain test of high-temperature C / SiC composites

ZHANG Yujie , PEI Weiqing , TANG Yijie , JIANG Hongchuan

2025, 45(1). DOI: 10.11823/j.issn.1674-5795.2025.01.05

[Abstract](483) [HTML](188) [PDF 24.93 M](643)

Abstract:
A thin film strain gauge fabrication method was proposed based on high-temperature inorganic glue flattening treatment, magnetron sputtering technology and atomic layer deposition (ALD), aiming at solving the problem of high-temperature strain measurement on the surface of C / SiC composite materials. The surface of the C / SiC composite material was flattened by brushing inorganic glue, and then a thin film strain gauge consisting of a Pt sensitive layer and a composite insulating layer was prepared using magnetron sputtering and atomic layer deposition technology. Specifically, the Pt sensing layer was prepared by direct current (DC) sputtering through complex surface patterning technology with a hard-mask, achieving a resistance of 75 Ω and a thickness of 450 nm. For the insulating layers, three types of composite insulating layers (YSZ / Al?O?, Al?O?-YSZ / Al?O?, and HfO?-YSZ / Al?O? composite layers with a thickness of 1.2 μm) were prepared via DC sputtering and atomic layer deposition. A comparative study was emphatically conducted to evaluate the high-temperature insulation performance of the three insulating layers. The results indicated that the HfO?-YSZ / Al?O? composite insulating layer exhibited the best performance, with an insulation resistance of 32.94 kΩ at 950 ℃ after multiple thermal cycles. Strain testing under a temperature range from room temperature to 600 °C revealed that the Pt strain gauge fabricated based on HfO?-YSZ / Al?O? composite insulation layer achieved a maximum gauge factor (GF) of 2.93. The minimum and maximum measurement errors were 0.01% (600 °C, 133.2 με) and 6.49% (200 °C, 133.2 με), respectively. The strain gauge exhibited superior high temperature stability and strain response. The research results provide a new technical solution for high-temperature strain measurement on the surface of C / SiC composite materials, which possessed positive significance for promoting the development of high-precision strain measurement technology for thermal structural components of hypersonic vehicles.

8 Development of a flexible pressure sensor and verification of its static / dynamic performance

YANG Shuiwang , FU Zhengwei , ZHAO Zhiliang , DU Yufeng

2024, 44(5). DOI: 10.11823/j.issn.1674-5795.2024.05.06

[Abstract](567) [HTML](262) [PDF 11.91 M](589)

Abstract:
In order to solve the complex problem of finely sensing the static pressure distribution and dynamic pressure changes on the wall during high-speed flight of aircraft, a capacitive flexible pressure sensor based on PDMS dielectric material was developed by finely matching the material concentration of PDMS-CNTs and bonding the electrode layer and dielectric layer of the sensor. The difficulty of interface friction and energy loss mismatch between electrode layer and dielectric layer was overcome. The static pressure distribution and dynamic pressure change of the sensor were verified by static/dynamic performance verification experiments. The results show that the developed sensor can detect the static pressure of 0.1 ~ 104.9 kPa, can realize the dynamic pressure detection under the vibration frequency of 10 ~ 2 000 Hz, and has good static/dynamic pressure sensing ability. The flexible pressure sensor can be applied to the complex curved structure of aircraft, and has a good application prospect in optimizing the aerodynamic shape of aircraft.

9 Research on calculation method of shear deformation of I-beam based on Timoshenko beam theory

XIN Yuxia , WANG Yong , FU Jiahao , NI Tianqi , QI Heyang

2023(5). DOI: 10.11823/j.issn.1674-5795.2023.05.05

[Abstract](910) [HTML](276) [PDF 1.83 M](2142)

Abstract:
Aircraft wings usually use I-beams as support structures. However, due to changes of the geometric parameters of the I-beams, theoretical calculations will be affected, and the choice of beam theory will directly affect the calculation results. At present, the existing deflection calculation of I-beams is mainly based on the Euler Bernoulli beam theory, without fully considering the shear deformation during beam bending. Therefore, this article proposes a calculation method for I-beams considering shear effects based on the Timoshenko beam theory, which is used to calculate I-beams affected by concentrated forces. By characterizing the effect of shear deformation on beam deformation, the law of action of shear deformation on the beam was obtained, and the deformation mechanism of shear deformation in the beam was explained. Research has shown that when the I-shaped cantilever beam is within a certain range near the fixed end and the span to height ratio of the beam is less than 5, the influence of shear deformation should be considered in the calculation. The theoretical results of internal force calculation obtained by this method are basically consistent with the results of simulation and electrical measurement method, and can be applied to practical engineering calculation.

10 Research progress on floating element wall shear stress sensors

FU Zhengwei , YANG Shuiwang , ZHANG Qi , SU Yiming , ZHANG Jie

2023(6). DOI: 10.11823/j.issn.1674-5795.2023.06.02

[Abstract](856) [HTML](233) [PDF 9.26 M](1050)

Abstract:
This paper introduces the types of floating elements and the measurement method of wall shear stress of floating elements. The basic principles and research status of capacitive, piezoresistive and optical wall shear stress sensors based on floating elements are described. The advantages and disadvantages of the three types of floating element wall shear stress sensors are analyzed. It is pointed out that the performance of the floating element wall shear stress sensor can be improved by optimizing the moving gap between the floating element and the sensor package, as well as the flatness between the floating element and the measured surface. The development direction of wall shear stress sensor with floating element in turbulent flow measurement, boundary layer transition judgment, aircraft safety maintenance and optimization of aircraft structure is also discussed. In the future, it is suggested that the MEMS technology can be developed, the back-end processing circuit and temperature compensation of the sensor can be optimized, and the moving gap and uniformity between the floating element sensor structures can be optimized by the integrated design and processing method to further improve the miniaturization of the floating element wall shear stress sensor, the sensitivity and accuracy of detecting the extremely low value of wall shear stress, and the reliability and accuracy of measurement.

11 Research on a multifunctional pressure calibration device

XUE Zhanjun , GONG Zheng , YU Chen , LI Zhixin

2024(1). DOI: 10.11823/j.issn.1674-5795.2024.01.10

[Abstract](604) [HTML](220) [PDF 949.45 K](753)

Abstract:
In order to solve the problems of a large number of pressure measurement equipment that needs to be calibrated, the scattered range, and the special and diverse kinds of media in the aircraft ground tests, this paper makes a theoretical analysis on the calibration principle and method of pressure measurement equipment, and designs an integrated pressure calibration device with multi-channel, multi-range and multi-media. The system has the functions of automatic control, acquisition and data processing. The calibration requirement of pressure measurement equipment for aircraft ground test has been practically solved, the calibration efficiency has been improved, and the application effect has been achieved.

12 Research on tracking loading method and device of wings with high aspect ratio

GUO Caiguohui , YANG Jun

2024(1). DOI: 10.11823/j.issn.1674-5795.2024.01.09

[Abstract](711) [HTML](422) [PDF 1.47 M](1418)

Abstract:
In the load calibration experiments of wings with high aspect ratio, the wings will bend and deform with the increase of load, resulting in a change in the direction of the normal load at the loading point, which affects the accuracy of the load calibration experiments. To solve this problem, a set of high aspect ratio tracking loading device was designed. The device controls the vertical displacement of the loading point through an electric cylinder, and the horizontal displacement of the electric cylinder through a displacement table. The linkage control system is used to keep the force exerted on the wing surface in the load calibration experiment perpendicular to the wing surface, so as to ensure that the load on the wing is always in the normal direction. The comparison experiment between the tracking loading and the vertical loading was performed, and the results showed that the correlation coefficient of the data obtained by the tracking loading reached 0.999, which was better than the correlation coefficient of 0.976 obtained by the vertical loading of the weight, which verified the effectiveness of the tracking loading device. This device possesses the advantages of compact size and straightforward operation, thereby offering support for advancing the research on the performance of high aspect ratio wings.

13 Research on calibration method of transient pressure probe rakes based on expansion shock tube

ZHAO Guosong , SHI Bo , LI Feng , CHEN Xiaosong

2024, 44(6). DOI: 10.11823/j.issn.1674-5795.2024.06.03

[Abstract](620) [HTML](279) [PDF 7.59 M](941)

Abstract:
In order to meet the calibration needs of large-size transient pressure probe rakes, a pressure probe rake calibration method based on expansion shock tube was proposed. The FLUENT software was used to simulate the dynamics of the shock wave in the shock tube, and the operation law of the shock wave and the change of pressure and density of the flow field were analyzed. The results showed that the pressure in the low-pressure section eventually became uniform after being affected by the incident shock wave, the reflected shock wave, the compression wave and its multiple reflections. The pressure measurement experiments were conducted by using the expansion shock tube device with soft and hard aluminum diaphragms. The results showed that the rise time was less than 9 ms and the duration of platform pressure was greater than 50 ms in the low-pressure section inside a 150 mm diameter of shock tube. This study has important reference value for the calibration of transient pressure testing systems in aero engine, aerospace, medical and other fields.

14 Research on torque measurement based on surface acoustic wave resonators

HUANG Mingjing , CHEN Zhijun , SUN Cong , ZHONG Ming , SU Piqiang

2024, 44(5). DOI: 10.11823/j.issn.1674-5795.2024.05.07

[Abstract](417) [HTML](157) [PDF 7.50 M](608)

Abstract:
In view of the current status and existing problems of the surface acoustic wave (SAW) torque measurement technology in theoretical analysis, algorithm design and experimental test, the torque measurement technology based on the SAW resonator (SAWR) is studied. According to the feature that the torque on the shaft is transmitted to the SAWR by the strain, the theory model of the strain loading in the Lagrange coordinates is established. The torque coefficient of frequency is defined as an important indicator for cuts optimization, and four SAWRs are designed and produced according to the principle of frequency division multiple access (FDMA). On the basis of the echo characteristics of the SAWR, the measurement methods of the SAWR resonance frequency and their characteristics are summarized. The wireless measurement system for static and dynamic torque are built respectively. The static system utilizes the method of frequency sweep for the signal strength measurement, which combines big step for rough sweep with small step for fine sweep for the purpose of enhancing real-time performance and improving the frequency measurement accuracy. The dynamic system employs the carrier frequency measurement method, and solves the problems of insufficient spectrum resolution and low torque measurement accuracy by the cubic spline interpolation in the frequency domain. The results show that the maximum measurement error of the static system does not exceed 1 N·m when the wireless distance exceeds 20 cm and the torque range is from -80 to 80 N·m; The maximum measurement error of the dynamic system does not exceed 3 N·m when the wireless distance exceeds 20 cm, the torque range is between 0 and 80 N·m, and the rotational speed does not surpass 600 r / min. The results validate the effectiveness of the torque measurement system based on the SAWRs, which provided a new approach for high-precision torque measurement.

15 Review of calibration techniques for strain field measurement systems based on Digital Image Correlation method

CHENG Shuai , ZHANG Dazhi , DUAN Xiaoyan , JIANG Yanhuan

2024, 44(3). DOI: 10.11823/j.issn.1674-5795.2024.03.06

[Abstract](982) [HTML](242) [PDF 1.99 M](1717)

Abstract:
This paper introduces the principle, application and development status of the strain field measurement system based on Digital Image Correlation (DIC), expounds the necessity of calibrating the system, and introduces the principles of representative calibration methods for DIC strain field measurement systems, such as four point bending calibration method, uniaxial tension calibration method, vertical loading calibration method and speckle transformation calibration method. The calibration dimension, calibration range, device cost, device complexity, metrological traceability and measurement uncertainty of various calibration methods are discussed, and the advantages and disadvantages of each calibration technology are compared and analyzed. It is pointed out that the accuracy of existing calibration methods can be improved by improving sensor performance, optimizing the measurement optical path, and enhancing the speckle quality. The development direction of calibration technology for strain field measurement systems based on DIC is discussed, and it is pointed out that future research should focus on the reliable generation and reproduction of large deformation fields, three-dimensional visualization of speckle patterns, and organic fusion of multiple calibration data to further broaden the scope of application of strain field calibration and effectively reduce the uncertainty in the measurement process.