A Configuration-Space Interrogation Approach to the Understanding and Design of Critical Load-Bearing Structures Susceptible to Buckling

预测一个结构在倒塌前可以安全承受的载荷是一个挑战。在其使用寿命期间，一个结构预计将在一个经常严峻和不断变化的环境中发挥作用，无论这是一个固体火箭助推器在升空期间;一个多层建筑在地震期间;一个筒仓在强风期间;一个飞机机翼在湍流期间;或一个海洋潜水器在深度受到巨大的压力。特别是细长圆柱结构的失效对几何形状的微小变化非常敏感，当它们确实失效时，通常是由于屈曲，通常是突然和灾难性的事件。由于其不可预测的行为，它们通常被过度设计。该奖项支持开发一种创新方法来理解细长结构的屈曲，特别是中空圆柱结构。评估承载能力的更合理的基础，包括适当的安全系数，将允许对给定结构的预期使用寿命进行更准确的预测，从而节省大量资金。这项研究对于优化部件更换、根据性能恶化情况安排维护以及最大限度地减少材料使用也很重要。经济设计和预防灾害是研究的长期利益。在进行这项研究期间，研究生和本科生将学习各种技能，包括结构测试，数学建模，增材制造，实验设计和数据分析。由于空心圆柱作为容器被广泛应用，从汽水罐、管道到飞机机身等，对国防和繁荣的发展有着重要的影响。这导致工程师依赖于相对保守的设计准则的基础上经验？击倒？因素新方法的主要目标不是试图预测高度非线性结构将屈曲的确切载荷，而是评估结构对冲击或干扰的鲁棒性：一种形式的构型空间询问。识别不稳定的平衡状态，并避免它们，是新的稳定性标准的一个关键特征。3D打印将被广泛使用。3D打印的几何精度和多功能性非常适合生产一系列高分辨率圆柱体，这些圆柱体将在实验室中进行彻底测试。还将进行数值模拟以进行核查。在这项研究中获得的基础知识将为理解结构稳定性做出重要贡献，并最终指导关键承载元件的设计和使用。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Predicting the load that a structure can safely withstand before it collapses is challenging. During its useful life-time, a structure is expected to perform within an often severe, and changing environment, whether this is a solid-rocket booster during lift-off; a multi-story building during an earthquake; a grain silo during strong winds; an aircraft wing during turbulence; or an ocean submersible subject to great pressure at depth. The failure of slender cylindrical structures, in particular, is sensitively dependent on small changes in geometry, and when they do fail, usually due to buckling, it is often a sudden and catastrophic event. Due to their unpredictable behavior, they are typically over-designed. This award supports the development of an innovative approach to understanding the buckling of slender structures in general, and hollow cylindrical structures in particular. A more rational basis for assessing load-carrying capability, including appropriate safety factors, will allow more accurate predictions to be made concerning the anticipated useful lifetime of a given structure resulting in tremendous savings. This research is also important for optimizing component replacement, scheduling maintenance based on deteriorating performance, and minimizing material usage. Economic designs and the prevention of disaster are long-term benefits of the research. During the conduct of this research, graduate and undergraduate students will learn a variety of skills including structural testing, mathematical modeling, additive manufacturing, experimental design, and data analysis. Since hollow cylinders are widely used as containers, ranging from soda cans to pipelines to pressurized aircraft fuselages, this project has important impact on national defense and prosperity.Testing thin cylinders under axial load typically leads to large scatter in the measured buckling load. This has led engineers to rely on relatively conservative design guidelines based on empirical ?knockdown? factors. Rather than trying to predict the exact load at which a highly nonlinear structure will buckle, the major goal of the new approach is to assess the robustness of a structure to shocks or disturbances: a form of configuration-space interrogation. The identification of unstable equilibrium states, and their avoidance, is a key feature of the new stability criteria. 3D-printing will be used extensively. The geometric precision and versatility of 3D-printing is ideally suited to producing a range of high-resolution cylinders that will be thoroughly tested in the laboratory. Numerical simulations will also be conducted for verification purposes. The fundamental knowledge gained in this research will provide an important contribution to the understanding of structural stability and ultimately guide the design and use of critical load-bearing elements.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.