Mechanical performance of 3D woven glass fiber I-beam composites with in-situ polyurethane foaming.

• Custom-built 3D weaving machine was used to weave 3D spacer glass fiber fabrics. • PU foaming was directly performed in the vacancies of 3D woven I-beam composites. • Up to 43 % compressive modulus increase was obtained via in-situ PU foaming. • Energy absorption was increased in LD-PUFFIC by 173 % under three-point bending. • Post-mortem mechanical test samples were monitored by fractography. 3D weaving of I-beam structures can potentially create delamination- and joint-free structures, expanding their use in engineering applications compared to metal or traditional laminated composite beams. In addition, polymeric foams can be utilized to fill the vacancies between the web and the flanges of I beams, improving the mechanical characteristics and the structural integrity with little to no weight penalty. Moreover, interposing an adhesive layer between the I beam and the foam structure can result in a more effective bonding which intensifies the structure's robustness. In this study, high-performance I-beam composites were produced by combining polymeric foams with 3D woven glass fiber composites. Low- and high-density polyurethane foams were successfully inserted between the web and the flanges of 3D woven glass fiber composites manufactured by the vacuum infusion process using the free-rise foaming method. Samples with adhesive films were also produced to assess and compare their effectiveness with the composites made solely of polyurethane foam and I beam. The increases in energy absorption capacity and compressive and flexural properties were analyzed under compressive and flexural (three-point bending) loading. The obtained results indicate that structural integrity under bending can be substantially improved with the in-situ foaming supported by adhesive layers. [ABSTRACT FROM AUTHOR]