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This experimental work investigates the effect of (0°/90°) and (+45°/–45°) plies position on failure modes and acoustic signals in carbon fiber reinforced polymer (CFRP) laminates under quasi-static tensile loading. Five stacking sequences, namely [(0°/90°)2/(±45°)2]S, [(0°/90°)/(±45°)/(0°/90°)/(±45°)]S, [(0°/90°)/(±45°)2/(0°/90°)]S, [(±45°)/(0°/90°)/(±45°)/(0°/90°)]S, and [(±45°)2/(0°/90°)2]S are fabricated by vacuum bagging process. Digital image correlation technique is used to establish strain and displacement fields in CFRP laminates during the tensile loading. Additionally, in situ acoustic sounds produced during specimen failure under tensile testing are correlated to crack formation. Finally, the two-parameter Weibull statistical analysis is employed to assess the reliability and repeatability of the experimental data. [ABSTRACT FROM AUTHOR]

The need for thin and highly deformable textile reinforcements is constant in sectors like thin composites, catching nets, and complex construction designs (like dome-shape). The conventional rectangular-patterned meshed wovens are used in thin composite structures as reinforcement at the commercial level. These woven textiles are bidirectional and exhibit approximately the same strength along both axes. However, these conventional rectangular-patterned mesh designs show poor impact stress distribution capacity. Interestingly, very thin and fine mesh designs are available in nature. One such example is the spider web structure. These structures have evolved with time and optimised their mesh pattern design for better impact damage resistance and load transfer. In this study, the basalt fibre reinforced mortar textile composites are considered for the investigation due to their growing interest in civil and construction applications. To demonstrate how the mesh geometry in textiles significantly influences the stress transfer, energy absorption, and deformation of reinforcements under various impact situations, three different geometries, (a) square shape mesh, (b) diamond-shaped mesh, and (c) bio-inspired spider web mesh, are modelled and meshed based on the reference geometry's meshing pattern and dimensions. The results of numerical simulations show that a meshed reinforcement design inspired by spider-orb-web has improved mechanical features compared to conventional square and diamond shape mesh designs under high velocity impact loading. [ABSTRACT FROM AUTHOR]

This study investigates the mechanical characteristics of basalt fiber/epoxy polymer composites (BPC) inspired by nature's higher‐order designs especially helicoidal structures found in fish scales. The present work includes the experimental analysis of 20‐layered bioinspired BPC composites in single helicoidal ([90/80/70/60/50/40/30/20/10/0]s), and double helicoidal ([130/40/120/30/110/20/100/10/90/0]s) layups. The hand layup technique, followed by the vacuum bagging method, is used to fabricate composite laminates. The layup design significantly influenced the mechanical properties of both helicoidal structures with different stacking sequences, including load capacity, deformation, energy absorption, and fracture modes. Interestingly, failure mechanisms demonstrated both bending and twisting (attributed to specific ply orientation, resulting in a twisting effect) occurring majorly under flexural loading, leading to improved energy absorption. The flexural strength of single helicoidal laminate was observed to be 28.8% higher than double helicoidal laminate design. On the other hand, the double helicoidal laminate showed 46.8% and 19.4% higher interlaminar shear strength (ILSS) and impact resistance properties, respectively, compared to the single helicoidal laminate design. Therefore, this comparative experimental analysis of both stacking structures provides insights into potential changes in conventional stacking sequences and enhances understanding of mechanical responses in bioinspired composites. Highlights: Mechanical characterization of bioinspired helicoidal laminates is done.The flexural strength of single helicoidal laminates is 28.8% higher than double helicoidal laminates.Double helicoidal laminates showed better interlaminar shear strength and energy absorption. [ABSTRACT FROM AUTHOR]