Nonlinear Localization for Shock Isolation of Flexile Structures

柔性结构冲击隔离的非线性定位

• 批准号: 0000060
• 负责人: Alexander Vakakis
• 金额: $ 18.04万
• 依托单位: University of Illinois at Urbana-Champaign
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-09-15 至 2003-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0000060&HistoricalAwards=false
• 关键词: Nonlinear; Localization; Shock; Isolation; Flexile

Alexander F. Vakakis / Lawrence A. Bergman, Univ. of Illinois at Urbana-ChampaignProposal No. CMS-0000060Proposal Title: Nonlinear Localization for Shock Isolation of Flexible StructuresProject Abstract:A unique response reduction strategy for complex structures subjected to shock-induced vibrations is proposed. The vulnerability of flexible structures to large magnitude transient inputs is well documented. Various methods have been proposed and, in some cases, implemented through which the reliability of these structures can be enhanced. Typical solutions include passive isolation and auxiliary damping devices, which have been employed for many years with varying degrees of success. The primary focus of the proposed research is the development of a new type of passive nonlinear shock isolation system for protection of flexible structures, based upon the concept of nonlinear localization. Here, rather than relying strictly on compliance and adequate "rattle space," the system takes induced vibrational energy and passively confines it to a preassigned secondary system away from the primary structure to be isolated, where it can be passively dissipated. The technique has been applied successfully to complex systems subjected to periodic loading, and in this project its efficacy under transient conditions will be studied, both analytically and experimentally.The project consists of three main tasks. First, a series of one-dimensional simulations and scale model experiments will be conducted to validate the concept of nonlinear localization in the context of protecting flexible structures subjected to large, transient inputs. Next, performance of a shock isolation system applied to a large, complex structure subjected to a series of multi-axial transients will be evaluated by modeling and simulation. Finally, a proof of concept experiment will be conducted using a larger scale structure on a multi-axis simulator.Through the use of nonlinear localization, the resulting shock isolation system will serve a dual purpose, providing protection in the linear regime for small-scale inputs and in the nonlinear regime for larger scale transients, while limiting the deformation ordinarily required for protection in the latter regime. The potential payoff is more compact and efficient passive protective systems.Impact of Budget Revision: The original two year budget provided for a total of two months (one month per year) of summer support for each of the two PI's and two calendar years of support for each of 2 Ph.D.-level graduate students. In order to reduce the overall budget from $261,868 to $180,000, summer support for each investigator is reduced to .10 month per year for each PI. This change will impact the summer progress of the graduate students, though hopefully not in a substantial way. Further, one Ph.D.-level student has been replaced by an M.S.-level student.On the experimental side, there will be no change to the one-dimensional experiment. We will, however, attempt to coordinate the multi-axial test program with another academic institution having an appropriate shaker facility. Assuming some coordination is possible at minimal cost, the goals of the project will remain fundamentally unchanged. The budget has been revised to reflect this.

亚历山大·瓦卡基斯（Alexander F. Vakakis） /劳伦斯·伯格曼（Lawrence A. Bergman），大学。伊利诺伊州在urbana-champaignproposoposal编号CMS-0000060港口标题：柔性结构摘要的非线性定位摘要：提出了一种受震动引起的振动的复杂结构的独特响应策略。柔性结构对大量瞬态输入的脆弱性已充分记录。已经提出了各种方法，在某些情况下可以通过这些方法来增强这些结构的可靠性。典型的解决方案包括被动隔离和辅助阻尼装置，这些设备已多年以不同程度的成功。拟议研究的主要重点是开发一种新型的被动非线性冲击隔离系统，以根据非线性定位的概念来保​​护柔性结构。在这里，该系统并没有严格依靠合规性和足够的“嘎嘎声空间”，而是采用诱导的振动能量，并被动地将其限制在远离主要结构的预签名二级系统中，可以被动地消散。该技术已成功地应用于经过定期加载的复杂系统，在该项目中，将在瞬态条件下进行分析和实验性研究其功效。该项目由三个主要任务组成。首先，将进行一系列一维模拟和比例模型实验，以验证在保护受大型瞬态输入的柔性结构的情况下，验证非线性定位的概念。接下来，将通过建模和仿真来评估受到一系列多轴瞬变的大型复杂结构的冲击隔离系统的性能。最后，将在多轴模拟器上使用较大规模的结构进行概念证明实验。通过使用非线性定位，由此产生的冲击隔离系统将达到双重目的，为小规模的线性方向提供保护输入和在非线性瞬变的非线性方案中，同时限制了后一种制度中保护所需的变形。潜在的回报更加紧凑，更有效地被动保护系统。预算修订：最初的两年预算总共提供了两个月（每年一个月）对两个PI的夏季支持和两个日历年的支持年份的夏季支持对于2个博士学位的研究生中的每一位。为了将整体预算从261,868美元降低到180,000美元，每个PI的夏季支持均减少到每年0.10个月。这种变化将影响研究生的夏季进展，尽管希望不会以实质性的方式。此外，一位博士学位的学生已被M.S.级学生所取代。在实验方面，一维实验不会改变。但是，我们将尝试与另一家具有适当振动筛设施的学术机构协调多轴测试计划。假设有可能以最低的成本进行协调，则该项目的目标将保持根本不变。预算已进行了修改以反映这一点。