Elastic behavior of composites reinforced by 3D printed tubular lattice braid textures Mohammad Amin Rahiminia and Masoud Latifi Department of Textile Engineering, Textile Excellence and Research Centers, Amirkabir University of Technology, Tehran, Iran, and Mojtaba Sadighi Department of Mechanical Engineering, Amirkabir University of Technology, Tehran, Iran Abstract Purpose – The purpose of this paper is to introduce an innovative transversal tubular braid texture and to study the elastic behavior of its 3 D printed structure comparatively to 3 D printed longitudinal tubular braid texture (maypole) to be used as reinforcement. Design/methodology/approach – Regarding the lack of proper machines for the production of the proposed texture, the structure of samples was produced as a tubular lattice braid texture using a 3 D printer with the fused deposition modeling method subsequent to simulation by Rhinoceros software. The produced specimens were composited by polyurethane resin. The composite samples were evaluated by the split disk mechanical test to obtain their hoop stress. The structures of the reinforced composites were theoretically analyzed by ANSYS software. Findings – The results of the mechanical test and theoretical analysis showed that the composites reinforced with transversal tubular lattice braid have higher strength compared to the composites reinforced with longitudinal ones. This assured that the composite reinforced by transversal tubular lattice braid is reliable to be used as high-performance tube for different applications. Originality/value – Further work is carried out to produce the innovated complex structure continuously by a specially designed machine and fibrous materials to reinforce tubular composites in an industrial continual process to be applied for high-pressure fluids flows. Keywords Texture-reinforced composite, 3D printer, Tubular braid texture, Split disk mechanical test, Polyurethane resin Paper type Research paper 1. Introduction The tubular braid textures can be used as protection covers of various materials as thin stripes to very thick and strong cables and more important as reinforcement in composite tubes. In many engineering applications, the combination of material properties is required, and there is no possibility of using one type of material that meets all desired properties. The solution is associated with composite materials. In general, reinforcements have high strength and low density, while matrices are typical materials with high toughness. If a composite is properly designed and constructed, the combination of reinforcement strength and toughness of a matrix will be achieved, which is not available in conventional materials (Mazumdar, 2002). Composite properties depend on factors such as the amount, size, shape and distribution of the reinforcement component, the mechanical properties of the matrix component and the interface between the reinforcement and the matrix components. Conventional engineering materials such as steel and aluminum are considered to have isotropic structure in the analysis. This is because they often exhibit the same properties in all directions. However, composite materials are considered as orthogonal isotropic structures in analysis. For example, the properties of fiber- reinforced composites often depend a lot on the measurement direction. To optimize the properties of composite materials, three parts should be optimized: the matrix, reinforcement and their interface. Therefore, by changing each part, depending on the application, different properties can be obtained. As a result, high mechanical properties can be obtained by changing the reinforcement component and producing different structures. Considering this point, as a further work, a high- strength braid texture might be proposed with a change in the structure of the reinforcement component. Braid textures are produced in a variety of forms, such as plate, two-dimensional, three-dimensional and tubular. The application of these materials is very high owing to their high capabilities. Flexibility in production, energy absorption, tensile properties and high torsion properties are the capabilities of braid textures (Gay, 2015). Another advantage of tubular braid composites is resistance to delamination because the entanglement of strands in their structures can act as resistant agents to the separation of layers (Tadiboni et al., 2013). The production of both transversal and longitudinal braid textures can be done from bottom to top and in some cases in horizontal direction. The motion system of production devices is rotational. Many research activities have been conducted on the production of braid texture, such as changing the texture angle and finding the optimum angle of the texture and producing composite specimens (Guyader et al., 2013). Composites prepared from The current issue and full text archive of this journal is available on Emerald Insight at: https://www.emerald.com/insight/1355-2546.htm Rapid Prototyping Journal 26/7 (2020) 1277–1288 © Emerald Publishing Limited [ISSN 1355-2546] [DOI 10.1108/RPJ-12-2019-0326] Received 26 December 2019 Revised 19 April 2020 Accepted 14 May 2020 1277