Natural fiber-reinforced polymer composites are gaining in popularity due to recyclability and availability. This research investigates how oil palm shell (OPS) filler materials impact the interlaminar shear and the dynamic properties of flax fiber-reinforced hybrid composites under cryogenic circumstances. Filler materials in two different proportions (0, 2, 4, and 6 wt.% OPS) and 40 wt.% flax fibers were used to make composites. The OPS filler-filled polymeric materials were invented through typical hand lay-up. The hybrid materials were imperiled to liquid nitrogen for varying amounts of time after production (15 and 30 min). According to the findings, OPS nanoparticles can be used as natural rather than artificial fillers. Furthermore, loading 4 wt.% OPS nanoparticles into organic fabric-strengthened epoxy polymeric materials during 15 min of cryogenic settings resulted in the best interlaminar shear and dynamic performances. The storage and loss modulus of the flax/epoxy composites were improved by adding a 4% OPS nanofiller. The improvement can be ascribed to the hardness and stiffness of the additional OPS nanofillers. The 4% nano-OPS/flax/epoxy hybrid nanocomposite’s damping factor was substantially reduced compared to the flax/epoxy composites. The OPS nanofiller limits the epoxy molecular chain’s free segmental mobility, resulting in a lower damping factor and enhancing the adherence among flax fibers and the epoxy resin. The shattered specimen of the hybrid materials was investigated using a scanning electron microscope.

Carbon nanotubes are established as a superior form of carbon. These have superior characteristics in terms of mechanical and chemical properties when compared to the other fibres available. High-strength fibres can be employed in a composite in a short form and mass-produced to fulfil high demands in composite applications. These composites can meet the strength requirements of nonstructural and structural components in a wide range of industries. Because of their light weight and excellent strength-to-weight ratio, these composites can be used in a wide range of applications. With Young’s modulus as high as 1 TPa and tensile strength up to 63 GPa, they are among the stiffest and strongest fibres. There is currently a lot of interest in using carbon nanotubes in a matrix to take advantage of these features. There have been a variety of polymer matrices used, and nanotube/ceramic and nanotube/metal composites are gaining popularity. The study of these materials is an ongoing process, as researchers and design engineers have yet to realize their full potential. Carbon nanotubes (CNTs) are used in this study to create the composite with the resin. The percentage of CNT used as a filler material in the composite is varied from 1 to 4 percent, with the best percentage chosen for optimal mechanical properties.

Friction stir welding is a solid‐state welding method that produces joints with superior mechanical and metallurgical properties. However, the negative effects of the thermal cycle during welding dent the mechanical performance of the weld joint. Hence, in this research study, the joining of aluminum tailor welded blanks by friction stir welding is carried out in underwater conditions by varying the welding parameters. The tensile tests revealed that the underwater welded samples showed better results when compared to the air welded samples. Maximum tensile strength of 229.83 MPa was obtained at 1000 rpm, 36 mm/min. The improved tensile strength of the underwater welded samples was credited to the suppression of the precipitation of the secondary precipitates due to the cooling action provided by the water. The lowest hardness of 72 HV was obtained at the edge of the stir zone which indicated the weakest region in the weld zone.