In this study, polyamide fibers, which stand out with their excellent plastic deformation and energy absorption capacity, were used as reinforcement materials, and in‐house manufactured composite specimens were subjected to low‐velocity impact (LVI), compression after impact (CAI) and tensile tests. Within this scope, one and two repeated drop tests were performed under 3 m/s velocity to determine LVI responses and how impact number affects the dynamic properties. CAI tests were also performed at a 1 mm/min crosshead speed, and mechanical properties for non‐impacted, one‐impacted, and two‐impacted specimens were determined. As a result of the outstanding plastic deformation capacity of thermoplastic fabrics, it is concluded that polyamide composites exhibited quite large strains. Furthermore, it was understood from the tensile responses that tensile stresses were carried by the thermoplastic fibers in two different regimes and significantly high toughness was obtained. Moreover, reductions in the maximum compression loads, critical buckling loads and axial stiffness were observed due to degradation in structural integrity after impact loads. Additionally, the utilization of recyclable thermoplastic polyamide fibers as reinforcement material instead of conventional reinforcement materials such as carbon and glass fibers provide more environmentally friendly products.

Hydraulic cylinders are used in many different areas from aviation to construction machinery and are generally manufactured using conventional steels that stand out with their low strength to weight ratio. In this study, it was aimed to design a hydraulic cylinder using composite materials to reduce cylinder weight. In this context, a novel composite hydraulic cylinder was designed, and numerical analyses for the composite portions of the hydraulic cylinder were carried out. For the numerical model, an aluminium liner and cylinder heads with the geodesic dome profiles were used, and composite layers were formed on their surfaces by using the Ansys ACP module. In the numerical

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In this study, low-velocity impact (LVI) responses for the thermoset and thermoplastic composites were experimentally investigated based on the fibre orientation, thickness and knitting architecture. To analyse dynamic responses such as bending stiffness, contact stiffness, total impulse, peak force, and absorbed/rebound energy, LVI tests at 2 and 3 m/s velocity, which correspond to the 11.2 and 25.2 J were conducted, respectively. Furthermore, impact-induced damages were examined by using Through Transmission Ultrasonic analyses and macro-scale visualizations. Results from the current study show that woven fabric reinforced composites exhibited more bending stiffness, contact stiffness and energy absorption capacity than unidirectional ones thanks to fibre alignments throughout the longitudinal and transverse directions. Moreover, resin material has favourable effects on the damage mechanisms, as expected. It has been concluded that utilization of the thermoplastic resin enabled the composite specimens to exhibit less delamination.

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