Steel tubular frames are often used to build a variety of structures because of their optimal mechanical properties and attractive forms. However, their joint fabrication involves a vast quantity of cutting and welding works, which induces high labour costs, material waste, and environmental pollution. The construction industry dominates the global carbon footprint, and it needs more sustainable products. Nature’s structures are also often tubular, and their joints (e.g. the knees of a human body, the nodes of trees and plants) are intrinsically optimized to maximize stiffness, resistance, and robustness. The 3D metal printing technology can enable a nature-inspired optimization of steel tubular joints, saving material waste and decreasing fabrication costs as well as the carbon footprint of the sector, since it is free from the constraints of traditional manufacturing. In this study, we designed new tubular joint shapes using solid isotropic material with the penalization (SIMP) method. The objective of the optimization was to maximize the structural performance of the node. The optimized node that used to be achieved after a complex manufacturing process composed of numerous cutting and welding operations, can now be 3D printed and then connected to the rest of the joint leading to a shorter fabrication time. We quantified the joints’ structural performance with different grades of optimization using non-linear finite element analysis. Compared with the conventional joint shapes, the new geometries offered a higher stiffness, resistance, and robustness. We performed a powder bed fusion simulation to analyze the residual stresses after production, and estimated the cost of the new solutions.

钢管框架由于其最佳的机械性能和引人注目的形式而经常用于建造各种结构。然而，它们的联合制造涉及大量的切割和焊接工作，这导致高昂的劳动力成本，材料浪费和环境污染。建筑行业在全球碳足迹中占主导地位，它需要更可持续的产品。大自然的结构通常也是管状的，它们的关节（例如人体的膝盖，树木和植物的结点）在本质上进行了优化，以最大程度地提高刚度，抵抗力和坚固性。3D金属打印技术可以实现自然灵感，优化钢管接头，节省材料浪费，降低制造成本以及该行业的碳足迹，因为它不受传统制造的限制。在这项研究中，我们使用惩罚性（SIMP）方法使用固态各向同性材料设计了新的管状接头形状。优化的目的是使节点的结构性能最大化。经过优化的节点可以在3D打印后进行复杂的制造过程，该复杂的过程由众多的切割和焊接操作组成，现在可以进行3D打印，然后将其连接到接头的其余部分，从而缩短了制造时间。我们使用非线性有限元分析，通过不同等级的优化来量化接头的结构性能。与传统的接头形状相比，新的几何形状具有更高的刚度，强度和坚固性。