Seismic Performance Evaluation of RC Columns Retrofitted by 3D Textile Reinforced Mortars

The paper investigates the seismic performance of rectangular RC columns retrofitted by a newly developed 3D Textile Reinforced Mortar (TRM) panel. The 3D-TRM used in this study consists of two components: self-leveling mortar and 3D textiles. Firstly, the flexural capacity of the 3D-TRM panel was investigated through the four-point flexural test. Secondly, a total of five specimens were constructed and experimentally investigated through static cyclic loading tests with constant axial load. One specimen was a non-seismically designed column without any retrofit, while the others were strengthened with either the 3D-TRM panel or conventional Fiber Reinforced Polymer (FRP) sheets. Experimental results in terms of hysteretic behavior, ductility ratio, and energy dissipation are investigated and compared with the cases of specimens with conventional retrofitting methods and without any retrofit. The maximum lateral force, ductility, stiffness degradation, and energy dissipation of RC columns with 3D-TRM panels were significantly improved compared with the conventional RC column. Therefore, it is concluded that the proposed retrofitting method can improve the seismic performance of non-conforming RC columns.

A FAST, AUTOMATIC MESHING PROCEDURE FOR COMPOSITES WITH INTERPENETRATING GEOMETRY

For decades, finite element analysis (FEA) has served as a ubiquitous tool, allowing engineers and scientists to gain critical insights into the behavior of complex composite materials. Despite the wide adoption of FEA, creating a conforming mesh for the most complex composite material models, such as mesoscale models of 3D textiles or microscale models of composites with reinforcement and irregular voids, remains a significant challenge. Much of the difficulty lies in the fact that many tools that create realistic surface geometries through process simulation often result in complex interpenetrations between objects. This paper proposes a pipeline of algorithms, some adopted from the visualization community and some novel, to automatically create a conforming, high-quality tetrahedral mesh for composite materials with complex geometries that may overlap. The details of a novel algorithm used to identify volume, surface, and edge features, while avoiding the use of a tolerance, are provided. Additionally, the paper describes three different methods to remove overlaps between tows. Finally, the algorithms are applied to a simple case with two orthogonal tows that overlap where they cross, demonstrating the result at each step and revealing the advantages and disadvantages of each of the three overlap removal algorithms.

Three-Dimensional (3D) Textiles in Architecture and Fashion Design: a Brief Overview of the Opportunities and Limits in Current Practice

Three-dimensional (3D) textiles prove characteristics in structures and performance which can be as attractive as to be the main object of a high number of research and applications in specialist markets (from small medical devices to large engineering structure) where the performance demands are severe ([1] in J Eng Fibers Fabr.). Nevertheless, much of the research has come from academia and there are few relatively small companies that, even if have expertise, lack the resources to develop R&D programmes. This prevents to broaden their application and to consolidate their use in new markets ([2] in Advances in 3D Textiles, pp 1-18). The paper aims at exploring the potentialities and future implementations of 3D textiles in architecture and fashion design. Both are fields where the demand to balance requirements of environmental sustainability, low time-consuming production and high performance is emerging, in their own respective scale. A set of more than 10 real case studies are collected and analysed with the aim at underlining the potentialities and the limits of 3D textiles in practice. The overview suggests that a more integrated workflow among modelling and simulation tools and bigger effort from industry to enhance manufacturing options and increase the interest on new material systems, bring about new application such as indoor environmental quality (IEQ) or human body protection.

Influence of Loading Orientation and Knitted Versus Woven Transversal Connections in 3D Textile Reinforced Cement (TRC) Composites

As previous research has shown, the use of 3D textiles does not only facilitate the manufacturing process of Textile Reinforced Cement (TRC) composites but also influences the mechanical properties of the TRC. A fundamental understanding of the contribution of the transversal connections in the 3D textile to the loadbearing behavior of 3D TRCs is, however, still lacking in the literature. Therefore, this research experimentally investigates two different parameters of 3D TRCs; firstly, the 3D textile typology, namely knitted versus woven transversal connections, is investigated. Secondly, the influence of the stress direction with respect to the orientation of these connections (parallel or perpendicular) is studied. A clear influence of the orientation is witnessed for the woven 3D TRC system while no influence is observed for the knitted 3D TRC. Both woven and knitted 3D TRC systems show an increased post-cracking bending stiffness compared to an equivalent 2D system (with the same textiles but without transversal connections), yet the woven 3D TRC clearly outperforms the knitted 3D TRC.

Tensile strength of 3D textiles reinforced cementitious composites plates

Tensile plate specimens with dimension of 450×100×40mm were cast with 3D glass fabric having three different thicknesses 6, 10 and 15mm to measure their tensile strength. Plates with one and two layers of chicken wires, as well as micro steel fiber of 0.75% volume fraction were tested under tensile for comparison with references plates. Cement mortar with 61.2MPa cube compressive strength at 28 days was designed for casing the plates. The results indicated that after cracking of the mortar the textile reinforcement adds a strain hardening trajectory, that cause failure to occurs at slightly higher load and a higher strain. The improvement in tensile strength at 28 days ranged between 5 to 30%, and for 90 days between 5 to 60% for the three types of fibres used. Based on the results a significant increase was indicated with micro steel fiber.

A weaving machine for three-dimensional Kagome reinforcements

Two-dimensional or three-dimensional (3D) textiles have been used as reinforcement in composite materials. Most techniques for weaving 3D textiles have been developed to obtain a compact preform so that the final product, the fiber-reinforced composite, has a high volume fraction of fibers with the least fraction of matrix for high strength. Contrarily, this article describes a novel technique for weaving a loose 3D preform called wire-woven bulk Kagome with polymer wires or threads. Firstly, the principle is explained by using a manual loom. A weaving machine is then designed with detailed mechanisms and its prototype is presented. Finally, the benefit, shortcomings, and future plans are discussed.