Journal of Experiental Mechanicals

法向压力影响电阻应变片测量结果的机制研究

Research on the mechanism of the effect of normal pressure on resistance strain gauge measurement

Received:December 08, 2023 Revised:February 09, 2024

英文关键词:strain measurement resistance strain gauges normal pressure Poisson effect boundary condition

基金项目:国家自然科学基金项目(12102257)；上海交通大学深蓝计划(SL2022ZD101)；电子元器件可靠性物理及其应用技术重点实验室开放基金项目(ZHD202104)

Author Name	Affiliation
DU Zhenxing	School of Ocean and Civil Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
ZHOU Shichao	School of Ocean and Civil Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
MA Shaopeng*	School of Ocean and Civil Engineering, Shanghai Jiao Tong University, Shanghai 200240, China

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中文摘要:

电阻应变片因具有可靠性高、测量成本低的特点而被广泛应用于工程装备变形测量领域。传统的测量场景中，应变片黏贴于构件自由表面，仅传递切向变形而不承受法向压力，现有应变片测量理论均基于此种情况推导建立。在一些特殊的测量场景中，如深海装备的应变测量，或者基于嵌入式应变片(如将应变片与复合材料一体化成型后嵌入构件内部)的应变测量等情况，应变片同时承受切向变形和法向压力作用，法向压力会导致应变片测量结果与常规场景不同。为此，需要研究法向压力对应变片测量的影响规律，厘清其影响机制，以保障这些特殊情况下测量结果的有效性。本文实验研究了不同加载历程法向压力对应变片测量结果的影响，并结合力学仿真方法分析了影响的机制。实验结果和分析表明：法向压力对应变片测量结果存在明显的影响；对于当代制备工艺生产的应变片，其影响是被测物构件的泊松效应和力学边界条件综合作用的结果，即应变片测得的结果是该点在泊松效应和力学边界条件综合作用下的真实应变。

英文摘要:

Resistance strain gauges are widely used in the field of deformation measurement of engineering equipment because of their high reliability and low measurement cost. In the traditional measurement scenario, the strain gauges are pasted on the free surface of the components and only transmit tangential deformation without bearing normal pressure. The existing strain gauge measurement theories are all based on the situation. However, in some special measurement scenarios, such as the strain measurement of deep-sea equipment, or the strain measurement based on embedded strain gauges (e.g., the strain gauges are embedded inside the components after integrated molding with composite materials), the strain gauges are subjected to both tangential deformation and normal pressure at the same time. As a result, the normal pressure causes strain gauges measurements to differ from those in conventional scenarios. Therefore, it is necessary to study the influence law of normal pressure on strain gauge measurement and clarify its influence mechanism in order to guarantee the validity of the measurement results in these special cases. This paper experimentally investigates the influence of normal pressure on the strain gauge measurement results under different loading history and analyzes the mechanism of the influence by combining it with the mechanical simulation method. The experimental results and analysis show that there is an obvious influence of normal pressure on the strain gauge measurement results. For the strain gauges produced by the contemporary preparation process, the influence is the combined effect of Poisson effect and mechanical boundary conditions of the measured components. In other words, the results measured by the strain gauges represent the real strains of the point under the combined effect of Poisson effect and mechanical boundary conditions.

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