非线性波调制在螺栓连接松弛检测中的研究
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- 英文论文题名：Study of Nonlinear Wave Modulation in Evaluating Loosening of Bolted Joints
- 论文作者：张振 ; 苏众庆 ; 肖毅
- 英文论文作者：Zhang Zhen ; Su Zhongqing ; Xiao Yi ; School of Aerospace Engineering and Applied Mechanics ; Tongji University ; Department of Mechanical Engineering ; The Hong Kong Polytechnic University
- 年：2016
- 作者机构：同济大学航空航天与力学学院;香港理工大学机械工程系;
- 论文关键词：螺栓连接件 ; 预紧力松弛 ; 非线性波调制 ; 波能量耗散 ; 复合材料
- 英文论文关键词：bolted joint ; bolt loosening ; nonlinear wave modulation ; wave energy dissipation ; composite
- 会议召开时间：2016-11-25
- 会议录名称：2016年航空科学与技术全国博士生学术论坛摘要集
- 语种：中文
- 分类号：TH131.3
- 学会代码：XBHH
- 会议名称：2016年航空科学与技术全国博士生学术论坛
- 会议地点：中国陕西西安
- 主办单位：西北工业大学研究生院、中国高校航空学院院长联席会
- 学会名称：西北工业大学航空学院
- 页数：1
- 文件大小：473k
- 原文格式：D
- 会议级别：全国
摘要
本文对比介绍了利用非线性波调制以及线性波能量耗散技术检测螺栓连接松弛状态的方法。在非线性声学检测方法中,利用低频抽运振动与松弛连接界面作用,使其产生"呼吸效应",从而导致与其作用的高频探测波动产生非线性失真(调制边带)。首先建立幂指数刚度模型来描述连接界面非线性接触刚度对于预紧力的依存关系,并理论求解出连接件非线性声学响应与界面非线性刚度的定性关系,进而定义基于调制边带的连接松弛检测非线性因子;在线性声学检测方法中,利用赫兹接触理论,定义基于波能量耗散的不同搭接形式连接件松弛检测线性因子。在后续实验验证中,两种检测因子对比用于复合材料以及金属多种连接件松弛状态检测。通过比较发现,线性检测因子只能用于单一形式金属连接件在一定预紧力范围内松弛状态检测,而非线性因子适用于所有连接件状态检测,并在早期螺栓松弛检测中展现优越的灵敏性。
Nonlinear wave modulation and linear wave energy dissipation techniques are comparatively introduced for the detection of bolt loosening in this study. In the nonlinear acoustic method, a low-frequency pumping vibration interacts with the interface of a loose joint to produce the "breathing effect", which introduces nonlinear distortions(i.e., generating modulation sidebands) into the high-frequency probing wave traversing the interface. Firstly, a contact model consist of power-law exponential stiffness was established to describe the dependence of the nonlinear contact stiffness on the applied torque. Subsequently, the qualitative relationship between the nonlinear acoustic responses and the nonlinear stiffness of the interface was derived theoretically and a nonlinear damage index was defined using the magnitude of modulation sidebands. In the linear acoustic method, a linear damage index was proposed based on wave energy dissipation though the Hertzian contact theory. In the subsequent experimental verification, the defined two indices were comparatively employed to identify bolt loosening in composite and metallic bolted joints with varied lap types. By comparison, the linear index was found only capable of evaluating the residual torque of a single-type metallic bolted joint in a limited torque range. On the other hand, the nonlinear index achieves an efficient detection for all investigated bolted joints with a superior sensitivity to the early bolt loosening.
Nonlinear wave modulation and linear wave energy dissipation techniques are comparatively introduced for the detection of bolt loosening in this study. In the nonlinear acoustic method, a low-frequency pumping vibration interacts with the interface of a loose joint to produce the "breathing effect", which introduces nonlinear distortions(i.e., generating modulation sidebands) into the high-frequency probing wave traversing the interface. Firstly, a contact model consist of power-law exponential stiffness was established to describe the dependence of the nonlinear contact stiffness on the applied torque. Subsequently, the qualitative relationship between the nonlinear acoustic responses and the nonlinear stiffness of the interface was derived theoretically and a nonlinear damage index was defined using the magnitude of modulation sidebands. In the linear acoustic method, a linear damage index was proposed based on wave energy dissipation though the Hertzian contact theory. In the subsequent experimental verification, the defined two indices were comparatively employed to identify bolt loosening in composite and metallic bolted joints with varied lap types. By comparison, the linear index was found only capable of evaluating the residual torque of a single-type metallic bolted joint in a limited torque range. On the other hand, the nonlinear index achieves an efficient detection for all investigated bolted joints with a superior sensitivity to the early bolt loosening.
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