Collaborative Research: Full-culm Bamboo as a Full-fledged Engineering Material

竹子在其天然的全秆（空心管）状态下，已经进化到能够有效地抵抗各种环境负荷。它的高强度、轻重量、快速生长、低能量和肥料需求都推荐竹子作为资源和能源密集型传统材料的可持续替代品。该项目的主要目标是建立框架和工具，以标准化评估全竹的材料和机械性能，从而将竹子置于与木材相同的基础上，作为传统建筑材料。通过对竹子等非传统材料的标准化，可持续发展的三重底线（社会公平、生态和经济）在各种国际背景下得到了提升，尤其是在社会公平方面。在发展中地区，非常规建筑材料的标准化服务于技术、生态和社会目标，使农村社区能够直接参与建造安全可靠的住房，并促进当地经济的可持续发展。特别是，该项目将通过利用波多黎各和海地的当地资源为美国学生赞助各种培训和教育活动来推进这些目标。本研究将巩固并显著扩展现有的知识体系，并建立基于材料和力学的全秆竹作为功能梯度纤维增强材料的行为本构模型。竹子行为的三种表现形式将被开发出来，形成评估工程应用中竹子的材料和机械性能所需的框架和工具。首先，详细的分析建模是理解竹作为功能分级材料的工程特性的关键。一个分析模型将通过创新的实验方法来开发，重点是建立基本力学性能的穿壁和沿秆变化。其次，如果要使全竹的广泛采用是可靠的，就必须对难以获得的、适合于现场试验方法的工程特性进行替代表示。所采取的方法将利用开发的分析平台，以开发可从实际现场试验中获得的工程设计特性的经验和基于力学的表示。最后，竹材料和机械性能的不确定性建模的新框架，可以是高度可变的，将使设计方程的可靠校准成为可能。该方法将包括随机生成的概率空间分布的机械性能实现到开发的分析模型。该项目将推进纤维增强材料和功能梯度材料的建模科学。事实上，更好地理解竹材料和秆的自然进化优化设计，包括其非均质性和可变性，将启发其他结构工程功能梯度材料的优化。

In its natural full-culm (hollow tube) state, bamboo has evolved to efficiently resist a variety of environmental loads. Its high strength, light weight, fast growth, and low energy and fertilizer requirements all recommend bamboo as a sustainable replacement for conventional materials that are resource and energy intensive. The primary objective of this project is to establish the framework and tools required to standardize the evaluation of the material and mechanical properties of full-culm bamboo and thereby place bamboo on the same footing as timber as a conventional building material. Through such standardization of non-conventional materials like bamboo, the triple bottom line of sustainable development (social equity, ecology, and economy) is advanced in a variety of international contexts, most notably in regard to social equity. In developing regions, standardization of non-conventional building materials serves technical, ecological and social goals empowering rural communities to directly participate in construction of safe and reliable housing as well as to sustainably develop local economies. In particular, this project will advance these goals by leveraging local resources in Puerto Rico and Haiti to sponsor a variety of training and educational activities for U.S. students.This research will consolidate and significantly extend the extant body of knowledge and establish materials- and mechanics-based constitutive models for the behavior of full-culm bamboo as a functionally graded, fiber-reinforced material. Three representations of bamboo behavior will be developed forming the framework and tools required to evaluate the material and mechanical properties of bamboo for engineered applications. First, detailed analytical modeling is key to understanding the engineering properties of bamboo as a functionally graded material. An analytical model will be developed informed by innovative experimental methods focused on establishing through-wall and along-culm variation of fundamental mechanical properties. Second, surrogate representation of difficult-to-obtain engineering properties suitable for field test methods is necessary if broad adoption of full-culm bamboo is to be reliable. The approach taken will leverage the analytical platform developed in order to develop both empirical and mechanics-based representations of engineering design properties that may be obtained from practical field tests. Finally, a new framework for modeling uncertainty in bamboo material and mechanical properties, which can be can be highly variable, will enable reliable calibration of design equations. The approach will include stochastic generation of probability spatial distributions of mechanical properties implemented into the developed analytical model. The project will advance the science of modeling both fiber reinforced and functionally graded materials. Indeed, a better understanding of the naturally evolved optimal design of the bamboo material and culm, including its nonhomogeneity and variability, will inspire optimization of other structural engineering functionally graded materials.