基于应变片全桥差动电路的悬臂梁杨氏模量测量实验  

The elastic modulus measurement of a bending cantilever beam based on full-bridge differential circuit with strain gauge

作　　者：代国红[1,2] 杨天宇 万书函 吴庆丰[1] 韩道福[1] 邓晓华[2] DAI Guohong;YANG Tianyu;WAN Shuhan;WU Qingfeng;HAN Daofu;DENG Xiaohua(School of Physics and Materials,Nanchang University,Nanchang 330031,China;Institute of Space Science and Technology,Nanchang University,Nanchang 330031,China)

机构地区：[1]南昌大学物理与材料学院,江西南昌330031 [2]南昌大学空间科学与技术研究院,江西南昌330031

出　　处：《南昌大学学报(理科版)》2024年第6期521-527,534,共8页Journal of Nanchang University(Natural Science)

基　　金：国家自然科学基金资助项目(12364019,2004155);江西省自然科学基金项目(20232BAB201037);江西省高等院校教学改革研究课题(JXJG-23-1-46);南昌大学教学改革研究课题(NCUJGLX-2023-149-64)。

摘　　要：杨氏模量是描述材料刚度和弹性性质的重要物理量,使用静态拉伸法测量金属丝杨氏模量是经典的大学物理实验项目之一。然而静态拉伸法并不适用于薄板类型材料的杨氏模量测量。本文采用电阻式应变片组建全桥差动电路并结合悬臂梁模型,设计了一种以薄板型金属材料为研究对象的新型杨氏模量测量装置。在本研究中,首先进行了理论分析,探讨了全桥差动电路输出电压灵敏度与应变片电阻的关系,并通过实验验证了全桥差动电路能够有效规避桥路电压非线性变化带来的影响,同时具有最大的电压灵敏度,从而提高了实验测量精度。其次,我们利用应变片搭建了全桥差动电路,使用拉力计对金属薄板材料自由端施加应力并测量应力大小,并通过应变电阻传感器组建的全桥差动电路测量薄板悬臂梁产生的应变,进而计算材料的杨氏模量。实验结果表明,本实验装置能精确测量多种金属薄板材料的杨氏模量,在材料力学性能测量方面具有重要的实用价值。Young’s modulus is a crucial physical quantity to characterizes the stiffness and elastic properties of materials.Determining the Young’s modulus of a metal wire using static tensile method is a classic physics experiment commonly conducted by college students.However,the static tensile method is unsuitable for the measurement of Young’s modulus of thin plate materials.This paper introduces a novel experimental device that utilizes a full-bridge differential circuit constructed with strain gauges and the cantilever beam model to measure the Young's modulus of thin plate metallic materials.Firstly,the theoretical analysis investigates the relationship between the output voltage sensitivity of the full-bridge differential circuit and the resistance of the strain gauge.The experiment demonstrates that the full-bridge differential circuit can effectively mitigate the impact of bridge voltage nonlinearity while maximizing sensitivity,thereby enhancing the measurement accuracy.Secondly,a full-bridge differential circuit is constructed using strain gauges,and a stress-meter is employed to apply and measure stress at the free end of the thin plate metallic material.The full-bridge differential circuit,equipped with strain resistance sensors,measures the strain induced in the thin plate cantilever beam to determine the Young’s modulus of the material.The experimental results demonstrate the accurate measurement of the Young’s modulus for various thin plate metallic materials using the proposed device,highlighting its significant practical value in characterizing material property.

关 键 词：电磁学 全桥差动 应变片 杨氏模量 

分 类 号：O441.5[理学—电磁学]