Enhanced Modeling of the Rocking and Overturning of Objects on a Moving Base

移动底座上物体摇摆和翻转的增强建模

• 批准号: 1200859
• 负责人: Andrew Smyth
• 金额: $ 31.26万
• 依托单位: Columbia University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-07-01 至 2016-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1200859&HistoricalAwards=false
• 关键词: Enhanced; Modeling; Rocking; Overturning; Objects

The rocking of objects and their overturning due to base motions such as earthquake excitations accounts for a substantial fraction of losses and in many cases functional disruption of facilities. While the rocking dynamics have been studied by several researchers since the 1960's surprisingly there are very large gaps in our ability to adequately simulate the response of the complex dynamics associated with the problem. This is a case where the combination of comparatively simple mechanical principles leads to highly complex nonlinear phenomena which are sensitive to parameter variations within the problem. The project will consider base deformability and damping properties, friction interactions at the base, uplift (when the body bounces during rocking), 3-dimensional analysis (which includes tri-axial base motion) with mass eccentricities of the object, non-rectangular base shapes, and more. The project plan focuses on the development of advanced computational simulations tools to model the complex nonlinear dynamics of rocking objects.In addition, an enhanced model would provide risk analysis of a wide variety of objects including everything from electrical transformers to masonry antiquities. Having such a model would greatly improve the ability to infer the historic earthquake record from the non-overturning or in some cases the overturning of ancient "precarious rocks" and structures. This improved understanding has the potential to better understand the historical events of earthquakes. In addition, features such as cart-like wheels (to simulate hospital medical equipment carts) will be added as extra degrees of freedom at the base, and also base restrainers (which may fail) at the beginning of the rocking response. In order to perform the inverse analysis, a probabilistic approach will be developed to determine what earthquakes (or sequence of earthquake) might have occurred over the history of a still standing ancient object. The research plan includes an experimental plan to be carried out on the PI's medium-scale shake table facility.

由于地震激发等基本动作而引起的物体的摇摆及其翻倒，这是损失的很大一部分，在许多情况下，设施的功能中断。自1960年代以来，几位研究人员已经对摇摆动力学进行了研究，但我们能够充分模拟与问题相关的复杂动力学的响应的能力存在很大的差距。在这种情况下，相对简单的机械原理的组合导致高度复杂的非线性现象，这对问题内的参数变化很敏感。该项目将考虑基础变形性和阻尼特性，基部的摩擦相互作用，隆起（当身体在摇摆过程中弹跳），三维分析（包括三轴基本运动）具有物体质量偏心，非矩形基础形状等。该项目计划着重于开发高级计算模拟工具，以建模摇摆对象的复杂非线性动力学。加上增强的模型将提供对各种对象的风险分析，包括从电气变压器到砌体古物的所有物体。拥有这样的模型将大大提高从非弯流或在某些情况下推翻古老的“不稳定岩石”和结构的历史地震记录的能力。这种改善的理解有可能更好地了解地震的历史事件。此外，将在底座上添加诸如车轮般的车轮（模拟医疗设备手推车）之类的功能，并在摇摆响应开始时基础约束器（可能失败）。为了进行反向分析，将开发出一种概率方法，以确定在仍然存在的古代物体的历史中可能发生了什么地震（或地震序列）。该研究计划包括一个实验计划，将在PI的中等规模的摇桌设施上执行。