Modeling vibrational behaviour of non-smooth large scale dynamical systems

模拟非光滑大型动力系统的振动行为

• 批准号: RGPIN-2015-03650
• 负责人: Yu, Shudong
• 金额: $ 1.6万
• 依托单位: Ryerson University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=669450
• 关键词: Modeling; vibrational; behaviour; non; smooth

Large-scale dynamical systems (LSDS) exist in every industry and in virtually every aspect of science and engineering. An LSDS consists of inter-connected sub-systems or components, transferring loads, energy and heat through interfaces, and more importantly interacting with each other through surface-to-surface frictional contact in a non-smooth manner. A mechanical system, used in manufacturing and other industries, has many components connected together by joints to complete various sophisticated tasks. During operations, each topologically complex component experiences elasto-rigid motion. As a result, a large number of degrees of freedom (DOF's) are required to describe time-varying configurations of all components with sufficient accuracy. Non-smooth LSDS can respond violently to disturbances and excitations in a deterministic or even chaotic manner, and can cause poor machine precision, excessive noise, accelerated component wear, etc. As examples of non-smooth large scale LSDS, vibration of a CANDU nuclear fuel string, excited by pulsating coolant flow, has caused severe wear damage to the pressure tube and fuel bundle component failure in the Canadian nuclear industry; a high-speed machine having flexible links and joints can lose its stability when operated near a critical speed; motion of a vibrating machine with gap-activated springs can become chaotic at certain operating points, which result in poor system performance. Study of vibration of non-smooth LSDS is of ultimate importance to both system design and maintenance engineers. ***In the proposed research, computational models will be developed to simulate vibrational behaviour of non-smooth LSDS with a focus on generic and efficient modelling of joints/interfaces with imperfections. This is a most challenging problem in the world dynamics community, which cannot be solved by a commercially available software. While the computer models are generic, the following two projects are pursued as applications and training of graduate students for employment in the Canadian industries: (i) vibration of a fuel bundle string in a CANDU reactor core, (ii) vibration of machine centre structure including drive, spindle and fixtures. Successful completion of the proposed research represents an important milestone achievement. The algorithms and computer models (1) allow researchers and engineers to model and understand vibrational behaviour of non-smooth LSDS under various excitations, and (2) provide manufacturers and operators with a tool for simulating the performance of a real mechanical system with imperfect interfaces/joints, and wear damage through frictional contact. These will result in reduction in product development time, and help reduce unnecessary and costly system shut-downs in the case of nuclear reactor. This will no doubt bring about economic and environmental benefits to Canada and the world. **

大型动力系统 (LSDS) 存在于每个行业以及科学和工程的几乎每个方面。 LSDS由相互连接的子系统或组件组成，通过界面传递载荷、能量和热量，更重要的是通过表面到表面的摩擦接触以非光滑的方式相互作用。用于制造业和其他行业的机械系统具有许多通过关节连接在一起的组件来完成各种复杂的任务。在操作过程中，每个拓扑复杂的组件都会经历弹性刚体运动。 因此，需要大量的自由度 (DOF) 来以足够的精度描述所有组件的时变配置。非光滑 LSDS 会以确定性甚至混沌的方式对扰动和激励做出剧烈响应，并可能导致机器精度差、噪声过大、部件加速磨损等。作为非光滑大规模 LSDS 的例子，CANDU 核的振动由脉动冷却剂流激发的燃料管柱已对加拿大核工业中的压力管造成严重磨损，并导致燃料管束组件失效；具有柔性连杆和接头的高速机器在接近临界速度时会失去稳定性；具有间隙激活弹簧的振动机的运动在某些操作点可能会变得混乱，从而导致系统性能不佳。非光滑 LSDS 振动的研究对于系统设计和维护工程师都至关重要。 ***在拟议的研究中，将开发计算模型来模拟非光滑 LSDS 的振动行为，重点是对具有缺陷的接头/界面进行通用且高效的建模。这是世界动力学界最具挑战性的问题，无法通过商用软件解决。虽然计算机模型是通用的，但以下两个项目作为研究生在加拿大工业就业的应用和培训：(i) CANDU 反应堆堆芯中燃料束串的振动，(ii) 机器中心结构的振动包括驱动装置、主轴和固定装置。拟议研究的成功完成是一项重要的里程碑式成就。这些算法和计算机模型 (1) 允许研究人员和工程师建模和理解非光滑 LSDS 在各种激励下的振动行为，(2) 为制造商和操作员提供一种工具，用于模拟具有不完美接口的真实机械系统的性能/关节，以及通过摩擦接触造成的磨损。这些将减少产品开发时间，并有助于减少核反应堆不必要且成本高昂的系统关闭。这无疑将为加拿大和世界带来经济和环境效益。 **