WrapToR hierarchical space frames made from natural material composites

桁架和空间框架是迄今为止开发的一些最有效的结构配置。它们利用高度非线性的结构尺度规律，将少量材料放入彼此相距很远的局部构件中，从而实现了非常高的性能水平，从而使它们能够以最小的应力平衡大的力和弯矩。这种结构通常由金属制成，性能非常好，但需要大量的能源和资源来提取、冶炼和成型。如果这种结构可以由天然材料制成，那么它们对环境的影响就会大大降低，它们可以被采用到更广泛的应用领域。然而，天然材料的机械性能往往低于金属或传统的复合材料。减轻较低机械性能的一种潜在方法是通过创建由本身就是桁架的构件制成的桁架结构来进一步利用几何结构。在之前的碳纤维复合材料的初步工作中，这些分层空间框架已经被证明是非常有前途的，并且通过采用布里斯托尔开发的专利桁架梁制造方法，包裹束增强（WrapToR）桁架制造方法，将它们应用于天然材料是可行的。WrapToR桁架是通过使用一种简单的纤维缠绕方式制成的，它将预制的纵向构件包裹在潮湿的复合材料束中，在固化后产生剪切构件的刚性网。然后，这些桁架梁可以通过连接结构组装成分层空间框架。这与天然材料固有的等级构成一起，将创造一种从整体结构到材料层面的协同等级秩序。由天然材料制成的WrapToR桁架和空间框架目前是一个很有前途但尚未开发的研究领域，需要开发实用、经济有效的方法来连接WrapToR梁。这项工作旨在开发WrapToR方法，设计一种可持续的低成本工艺，用于从天然材料中生产桁架和空间框架。为了实现这一目标，我们设定了以下目标：-开发WrapToR方法，以最大限度地提高天然材料桁架结构的结构性能，旨在考虑和利用天然材料的独特性。-对天然材料WrapToR桁架进行实验测试，以表征使用天然材料产生的独特行为，这可能与之前测试过的WrapToR桁架不同。确定结构性能、结构失效、材料特性和桁架几何之间的关键关系。然后使用计算建模和优化来设计单个桁架和分层空间框架。-研究相关的、现有的、现代的和传统的连接桁架和梁的方法，以便开发一个实用的、经济有效的过程，将单个WrapToR桁架连接到分层空间框架中。这些目标的最终目标是制造一个全尺寸的天然材料WrapToR分层空间框架演示器，用于相关的真实世界应用，可以在实际负载条件下进行测试。

Trusses and space frames are some of the most efficient structural configurations developed to date. They achieve very high levels of performance through taking advantage of highly non-linear structural scaling laws by putting small amounts of material into localised members which are spaced far away from each other, allowing them to balance large forces and bending moments with minimal stress. Such structures are typically made from metals, which provide very good performance, but require large amounts of energy and resources to extract, smelt, and form. If such structures could instead be made from natural materials then their environmental impact could be significantly lowered and they could be adopted to a much wider range of applications. However, natural materials tend to have lower mechanical performance than metallic or traditional composite solutions. One potential way of mitigating the lower mechanical properties is to further exploit geometry by creating truss structures made from members which are themselves trusses. These Hierarchical Space Frames have been shown to be very promising in previous initial work with carbon fibre composite materials, and applying them to natural materials is made tenable through adoption of a patented truss beam manufacturing method being developed at Bristol, the Wrapped Tow Reinforced (WrapToR) truss manufacturing approach.WrapToR trusses are made by using a simple adaptation of filament winding that wraps pre-made longitudinal members in a wetted composite tow to produce a rigid web of shear members when cured. These truss beams can then be made into Hierarchical Space Frames by assembling them with joint structures. This, alongside the innate hierarchical makeup of natural materials, would create a synergistic order of hierarchy from the global structure down to the material level. WrapToR trusses and spaceframes made from natural materials are currently a promising but unexplored area of research, and practical, cost effective methods for joining WrapToR beams need to be developed. This work aims to develop the WrapToR method to devise a sustainable and low cost process for producing trusses and spaceframes from natural materials. To fulfil this aim the following objectives are set:- Develop the WrapToR method to maximise structural performance of natural material truss structures, aiming to account for and exploit the unique features of natural materials. - Experimental testing of natural material WrapToR trusses to characterise unique behaviour that is produced as a result of natural materials being used, that may differ from previously tested WrapToR trusses. Determining key relationships between structural performance, structural failure, material properties and truss geometry. Then using computational modelling and optimisation to design both individual trusses and Hierarchical Space Frames.- Investigate relevant, existing contemporary and traditional methods for joining trusses and beams in order to develop a practical and cost-effective process for joining individual WrapToR trusses into hierarchical space frames.These objectives will culminate with the manufacture of a full-scale natural material WrapToR Hierarchical Space Frame demonstrator for a relevant, real world application that can be tested under realistic loading conditions.