EAGER: DREAM-B: Collaborative Research: Moldable and Wave Tunable Materials for Complex Freeform Structures

飓风、龙卷风和地震等自然灾害对美国构成持续威胁，可能导致经济损失和生命损失。不可预测的天气模式导致更严重和更频繁的自然灾害，因此，减轻灾害对建筑结构的影响对于灾后国家福利和繁荣的持续性至关重要。除了能够承受各种极端事件的建筑结构之外，现代和未来的建筑已经转向复杂的自由形式结构，超越简单的几何形状，以实现美观的结构并有效利用空间。 同时解决所有上述问题的解决方案将需要重新定义建筑材料设计和部署中的一些传统范例。 EARLY概念探索性研究资助（EAGER）将研究一种新的建筑材料方法，用于建筑表皮和立面，可塑造各种复杂的几何形状，同时能够操纵赋予建筑物的波浪并耗散高速风的能量。 通过浮雕切割由木材和金属制成的具有某些微观结构图案的实心板来实现可模制性，这是一种低成本工艺，因此适用于建筑行业。 虽然浮雕切割促进了柔性表面，但这种方法通常降低了面板的承载能力，这可能是不期望的。 这项研究将提供一种手段，有可能把切割方法的缺点变成优点，即，利用切割图案来调整动态特性以更好地抵抗危险载荷。 由于建筑的性质，切割表面预计将显示广泛的波和振动控制和能量耗散机制。 为建筑物配备重定向、定位、捕获和耗散能量的能力，而不仅仅是抵抗冲击力，可以带来更有效的减灾策略。这项研究可以通过将复杂的自由形状推向标准实践来推进结构工程，这种标准实践将美学论点，建筑性能要求和材料设计考虑因素交织在一起。更重要的是，自由形式的复杂形状可以为建筑物提供超出其默认承重和遮蔽能力的额外功能。 该项目将为本科生和研究生提供跨学科的专业和研究培训机会。 项目数据将在NSF支持的自然灾害工程研究基础设施（NHERI）数据库（https：//www.example.com）中存档并公开提供。www.DesignSafe-ci.org本研究旨在提供有关复杂的自由形状的几何形状，微观结构形态，组成特性（粘弹性和非弹性变形）之间的相互作用的基础知识，以及建筑材料中的波传播和能量耗散的机制。一种被称为浮雕切割（或切口）的技术将被用来赋予薄材料片规定的弯曲形状和表面图案。这种模式化的目的是双重的。首先，它将允许将平板模塑成几乎无限的复杂自由形状阵列，以满足各种功能和美学建筑需求。其次，它将诱导微观结构的几何形状和属性调制，可以帮助操纵广泛的波和振动事件，通过能量吸收和耗散机制。在基于模拟的设计阶段探索通过切口可用的设计空间后，自由形式的组件将被制造，成型和测试。在实验室样本的设计和测试中，将考虑模拟高速风的动态载荷的激励，以实现与实际建筑结构中使用的现实自由形式结构中观察到的应力和变形场相似的应力和变形场。 这项研究是高风险和高回报的，因为它将大大偏离传统的建筑方法：1）它将导致建筑设计的范式转变，其中自由形式的复杂形状将被证明可以提供更好的抗动荷载能力; 2）它将为自由形状引入一种新的大胆的模块化制造理念，这将产生最小的材料浪费，消除了对模具铸造的需要，并简化了材料运输的物流; 3）它将和谐地融合动态性能和架构约束-这两个要求通常被认为是相互排斥的-通过利用复杂形状和微观结构图案的内在机械和美学属性。该奖项反映了NSF的基金会的使命是履行其法定使命，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。

Natural disasters, such as hurricanes, tornados, and earthquakes, pose a continuous threat in the United States, which can result in economic losses as well as loss of life. Unpredictable weather patterns have led to more severe and frequent natural disasters and, therefore, mitigating the impact of hazards on building structures is important for continuity in national welfare and prosperity following a disaster. Aside from building structures that can sustain various extreme events, modern and future architecture has shifted towards complex freeform structures, beyond simple geometries, to achieve aesthetically pleasing structures and to make efficient use of space. A solution that simultaneously addresses all the above issues will require redefining some of the conventional paradigms in construction material design and deployment. This EArly-concept Grant for Exploratory Research (EAGER) will investigate a new construction material approach for building skins and facades that are moldable to various complex geometries and, at the same, have the ability to manipulate waves imparted to the buildings and dissipate energy from high velocity winds. The moldability will be achieved by relief cutting solid panels made of wood and metals with certain microstructural patterns, which is a low-cost process and hence suitable for the building industry. While relief cutting promotes flexible surfaces, this approach generally reduces the load carrying ability of the panels, which may not be desirable. This study will provide a means to potentially turn the disadvantage of the cutting method into an advantage, i.e., utilizing the cut patterns for tuning the dynamic properties to better resist hazard loadings. Because of the architected nature, the cut surfaces are expected to display a wide range of wave and vibration control and energy dissipation mechanisms. Equipping buildings with the ability to redirect, localize, trap, and dissipate energy, instead of merely resisting the impacted forces, can lead to a more efficient hazard mitigation strategy. This research can advance structural engineering by pushing complex freeform shapes to a standard practice that intertwines aesthetic arguments, building performance requirements, and material design considerations. To a greater impact, freeform complex shapes can provide buildings with additional functionalities beyond their default load bearing and shelter capabilities. This project will provide undergraduate and graduate students with interdisciplinary professional and research training opportunities. Project data will be archived and made publicly available in the NSF-supported Natural Hazards Engineering Research Infrastructure (NHERI) Data Depot (https://www.DesignSafe-ci.org). This research aims to provide fundamental knowledge regarding the interplay between complex freeform geometries, microstructural morphologies, constituent properties (viscoelastic and inelastic deformations), and mechanisms of wave propagation and energy dissipation in architectural materials. A technique known as relief cutting (or kerfing) will be used to endow thin material sheets with prescribed curved shapes and surface patterns. The objective of such patterning is two-fold. First, it will allow molding flat plates into a nearly endless array of complex freeform shapes to fulfill a variety of functional and aesthetic architectural needs. Second, it will induce a microstructural geometry and property modulation that can help manipulate a wide range of wave and vibration events, through energy absorption and dissipation mechanisms. After a simulation-based design stage exploring the design space available via kerfing, freeform components will be fabricated, molded into shape, and tested. In the design and testing of laboratory specimens, excitations that mimic the dynamic loads of high velocity winds will be accounted for to realize stress and deformation fields similar to those observed in realistic freeform structures used in actual architectural structures. This research is high risk and high reward as it will be a significant departure from traditional construction methodologies: 1) it will lead to a paradigm shift in building design, in which freeform complex shapes will be demonstrated to offer better resistance to dynamic loadings; 2) it will introduce a new and bold modular fabrication philosophy for freeform shapes that will generate minimal material waste, eliminate the need for mold casting, and simplify the logistics of material transportation; and 3) it harmoniously will blend dynamic performance and architectural constraints - two requirements that are often perceived to be mutually exclusive - by taking advantage of the intrinsic mechanical and aesthetic attributes of complex shapes and microstructural patterns.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.