RIA: Dynamic Loosening and Tightening of Threaded Fasteners by Vibration

RIA：通过振动动态松开和拧紧螺纹紧固件

• 批准号: 9210331
• 负责人: Daniel Hess
• 金额: $ 7.92万
• 依托单位: University of South Florida
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-09-01 至 1995-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9210331&HistoricalAwards=false
• 关键词: RIA; Dynamic; Loosening; Tightening; Threaded

Threaded fasteners have found ubiquitous use in many systems and structures. Although frequently overlooked, fasteners represent a complex and often critical design element. To some extent, all fasteners are subjected to unsteady loading. Yet the behavior of threaded fasteners under such conditions is still poorly understood. Existing analyses of threaded fasteners under vibration are based on static equilibrium conditions with supporting data limited to only low-frequency conditions. Such analyses suggest that only a net loosening action can occur. However, preliminary experiments show that when a broad range of vibratory conditions are considered, alternate ranges of frequencies are found in which either a loosening or a tightening action occurs. The goals of this research are to perform well- controlled measurements of the dynamic forces and motions of threaded fasteners under a wide range of dynamic conditions and to develop appropriate nonlinear dynamic models of threaded fasteners which capture and explain the dynamic loosening and tightening motions. The models will accommodate the interaction of friction and vibration as well as the dynamic constraints and nonlinearities inherent to threaded components. The results of the work are expected to be of fundamental engineering interest and have immediate use in the design of joints in many critical applications.***//

螺纹紧固件已普遍用于许多系统中， 结构.虽然经常被忽视，但紧固件代表了 复杂且通常是关键的设计元素。在某种水平上都对 紧固件承受不稳定的载荷。然而， 螺纹紧固件在这种情况下仍然很差， 明白螺纹紧固件的现有分析 振动基于静态平衡条件， 支持数据仅限于低频条件。等 分析表明，只能发生净松动作用。 然而，初步实验表明，当广泛的 考虑振动条件， 频率发现，无论是松动或收紧 行动发生。这项研究的目标是表现良好- 动态力和运动的受控测量 在各种动态条件下使用螺纹紧固件， 建立适当的螺纹非线性动力学模型， 捕捉并解释动态松动的紧固件， 收紧动作。这些模型将适应相互作用 摩擦和振动以及动态约束， 螺纹部件固有的非线性。的结果 这项工作预计将是基本的工程利益 并可直接用于许多关键节点的设计， 应用程序。*/