Tailoring of the Elastic Postbucking Response of Cylindrical Shells: A Route for Exploiting Instabilities in Mechanical Systems

弹性失稳是指结构元件的压缩承载能力突然丧失，传统上被认为是失效极限。然而，不稳定行为涉及结构几何形状的突然变化和累积能量的释放。因此，一种新的思维方式正在出现，利用细长结构的不稳定响应的目的，似乎是迅速增加和多样化。圆柱壳是最受不稳定性影响的结构元件之一（通常被视为一种负面特征），但它们的几何形状为控制其不稳定响应提供了独特的机会，这可以以可恢复的方式显示多个不稳定过渡。研究假设是，圆柱壳可以设计，使其不稳定的响应是通过最佳的几何和材料刚度分布在壳体表面上控制。研究结果将为开发利用不稳定性的材料和设备创造新的可能性，这些材料和设备用于传感，驱动，控制，能量收集和能量耗散等应用;这些进展反过来也可以促进新型智能，主动和多功能材料和结构的开发。该项目将培养一名博士。学生和教育和推广组件将扩大访问该项目的核心知识，本科生和高中student.The核心研究思想是，在远弹性后屈曲响应的圆柱壳的功能可以充分的特点，修改，并可能定制。感兴趣的功能不是初始弹性刚度或第一分叉载荷，而是具有多个稳定到不稳定过渡的响应，平衡路径加载刚度，在临界点过渡时释放的动能，以及在循环加载过程中耗散的能量。拓扑和形状优化技术将得到扩展，以实现所需的响应和实验将验证计算设计和基于有限元的模拟。分析和设计框架将开发轴向加载圆柱可控弹性后屈曲行为。关键的创新将证明，圆柱壳的弹性后屈曲响应可以通过壳体表面上的材料和几何特征的设计来定制，从而将传统上被视为不可取的行为转化为智能材料和结构的使用机会。该研究将为控制和设计圆柱壳弹性后屈曲响应的程度和方法提供新的知识，这将为可剪裁结构不稳定性的使用提供新的概念和指导。

Elastic instability, which refers to the sudden loss of compression load carrying capacity of a structural element, is traditionally considered a failure limit. Yet, unstable behavior involves a sudden change of the structure's geometry and the release of accumulated energy. Thus, a new way of thinking is emerging for using the unstable response of slender structures for purposes that seem to be rapidly increasing and diversifying. Cylindrical shells are among the structural elements most affected by instabilities (commonly seen as a negative trait) but their geometry provides unique opportunities for controlling their unstable response, which can display multiple unstable transitions in a recoverable manner. The research hypothesis is that cylindrical shells can be designed such that their unstable response is controlled through optimal geometric and material stiffness distributions on the shell surface. The research findings will create new possibilities for the development of materials and devices that use instabilities for applications such as sensing, actuation, control, energy harvesting, and energy dissipation; advances that in turn could also facilitate the development of novel smart, active and multifunctional materials and structures. The project will allow training of a Ph.D. student and educational and outreach components will broaden access to the project's core knowledge to undergraduate and high-school students.The core research idea is that the features in the far elastic postbuckling response of cylindrical shells can be fully characterized, modified, and potentially tailored. The features of interest are not the initial elastic stiffness or the first bifurcation load, but a response with multiple stable to unstable transitions, the equilibrium path loading stiffnesses, the released kinetic energy at critical point transitions, and the dissipated energy during cyclic loading. Topology and shape optimization techniques will be expanded to achieve the desired response and experiments will validate computational designs and finite-element based simulations. Analysis and design frameworks will be developed for axially loaded cylinders with controllable elastic postbuckling behavior. The key innovation will be proving that the elastic postbuckling response of cylindrical shells can be tailored through the design of material and geometric features on the shell's surface, thus transforming a behavior traditionally seen as undesirable into an opportunity for use in smart materials and structures. The research will generate new knowledge on the extent and means to control and design the elastic postbuckling response of cylindrical shells, which will provide new concepts and guidance for the use of tailorable structural instabilities.