Folded plate structures made of cementitious composites

利用折纸原理的折叠技术在工程学科中越来越受欢迎，也为具有承载功能的折叠结构领域开辟了新的机遇。结合柔性纺织织物不断增强的新型水泥基复合材料，折叠技术为基于形式服从力原理的轻量化结构的设计和制造提供了一种创新方法。由于制造过程的高适应性，该方法适合大规模定制，符合高可变性和经济生产的要求。在第一个项目期间，开发了水泥基折叠结构设计和制造方法的基本组成部分。用于模拟折叠过程和基于几何的寻形方法的新算法已在数学上制定并作为称为oricrete的模拟工具包中的插件实现。在此基础上，开发了基于吉村折痕图的单曲面壳折痕控制装置，并对其进行了验证。目标配置已被灌浆固定在折痕线。对注浆折痕线的力学性能进行了弯曲、拉伸、横向和剪切载荷试验。使用oricrete工具自动生成的有限元模型对其承载行为进行了分析。第二个项目阶段的目标是扩展设计和生产方法，采用高效的基于静态的形式查找算法和结合几种折叠方法的制造策略。提出的概念的可行性将代表演示对象进行评估。特别是，反映折痕线刚度特性的寻形方法应在oricrete工具包中开发和实现。这一发展将满足对反映机械性能和可折叠性限制的有效寻形方法的普遍需求。所开发的基于几何和静力学的寻形方法和算法将用于分析几种已知折痕图案的可成形性和静态性能。该找形方法将通过几何和物理上的非线性承载行为分析进行验证。开发的制造策略将用于生产几个薄折叠样品，以实验验证模拟结果。作为该项目的最终目标，将建造一个由几个折叠部分组成的折叠屋顶结构，作为开发方法的示范。

The folding technique exploiting principles of origami is becoming increasingly popular in engineering disciplines and opens up new opportunities also in the field of folded structures with load-carrying function. In combination with novel cement-based composites continuously reinforced with flexible textile fabrics, the folding technique provides an innovative method for design and manufacturing of light-weight structures based on the principle of form follows force. Due to the high adaptivity of the manufacturing process the method lends itself to mass-customization as it complies with the requirements on high variability and economic production. In the first project period, basic components of the design and manufacturing methodology for cement-based folded structures have been developed. New algorithms for the simulation of the folding process and for geometrically based form-finding methods have been mathematically formulated and implemented as plug-ins in the simulation toolkit called oricrete. Based on the conducted simulations, devices controlling the folding process have been developed and validated for singly curved shells based on the Yoshimura crease pattern. The target configuration has been fixed by grout in the crease lines. The mechanical properties of the grouted crease lines have been tested for bending, tensile, transverse and shear loadings. The load-carrying behavior has been analyzed using a finite element model automatically generated by the oricrete toolkit. The goal of the second project period is the extension of the design and production methodology with efficient statically based form-finding algorithms and manufacturing strategies combining several folding approaches. The feasibility of the proposed concepts is to be evaluated on behalf of demonstrator objects. In particular, form-finding methods reflecting the crease line stiffness properties shall be developed and implemented in the oricrete toolkit. This development will address the general need for efficient form-finding methods reflecting the mechanical properties and foldability constraints. The developed methods and algorithms for a geometrically and statically based form-finding will be employed to analyze the formability and static performance of several know crease patterns. The form-finding methods will be validated by geometrically and physically nonlinear analysis of the load-carrying behavior. The developed manufacturing strategies will be used to produce several thin folded specimens for the experimental validation of the simulation results. As a final goal of the project a folded roof structure consisting of several folded segments will be built as a demonstrator of the developed methodology.