The present research work is aimed to investigate the effect of infill pattern, density and material types of 3D printed cubes under quasi-static axial compressive loading. The proposed samples were fabricated though 3D printing technique with two different materials, such as 100% polylactic acid (PLA) and 70% vol PLA mixed 30% vol carbon fiber (PLA/CF). Four infill pattern structures such as triangle, rectilinear, line and honeycomb with 20%, 40%, 60%, and 80% infill density were prepared. Subsequently, the quasi-static compression tests were performed on the fabricated 3D printed cubes to examine the effect of infill pattern, infill density and material types on crushing failure behaviour and energy-absorbing characteristics. The results revealed that the honeycomb infill pattern of 3D printed PLA cubic structure showed the best energy-absorbing characteristics compared to the other three infill patterns. From the present research study, it is highlighted that the proposed 3D printed structures with different material type, infill pattern and density have great potential to replace the conventional lightweight structures, which could provide better energy-absorbing characteristics.

Economic and environmental concerns lead the researchers toward development of sustainable and renewable materials of which reinforced composites are part of. The abundantly available natural fibers have attracted the researchers to study their performance as reinforcements and feasibility for making automobile components. The performance of composite materials is mainly assessed through their mechanical properties. However, natural fibers to date were mainly used as reinforcements to create bulk composite components with reduced cost rather than improved mechanical performances. Among the methods available for improving mechanical properties of the natural fiber composites, combined mercerization treatment, hybridization, and incorporation of fly ash fillers in the matrix are the best solutions. Therefore, the objective of this research is to evaluate the tensile properties of hybrid kenaf/glass composites with and without fly ash particulate filler as per ASTM standards. Moisture absorption behavior and its effect on the tensile properties of hybrid composites are also investigated. The results revealed that the addition of 10wt % fly ash particles with natural fiber composites increased the tensile strength of composites while hybridization with glass fibers reduced the water absorption properties.

In recent years, light-weight nano composite materials have been progressively employed in the aviation, defense, naval and automotive manufacturing applications owing to their outstanding mechanical and crashworthiness characteristics. In this regard, nano composite cylindrical tubes could be significantly utilized as energy absorbing elements for dissipating the impact energy during vehicle collisions. The present research study aimed to examine the lateral crashworthiness response of Multi-Walled Carbon Nano Tubes (MWCNT) filled epoxy composite (basalt fabric and glass fabric) tubes of three different inner diameters using quasi-static crushing experiments. Crushing profiles and crush force–deformation curves of all the recommended typical tube samples are computed and discussed elaborately. The results obtained revealed that better crashworthiness characteristics of MWCNT reinforced epoxy composite tubes with a larger diameter, were owing to more promising crushing modes occurring during lateral compression. It is also found that the lateral crashworthiness response of the MWCNT filled glass fabric epoxy composite tubes was marginally superior to that of the MWCNT filled basalt fabric epoxy composite tubes. However, both the recommended composite cylindrical tubes with nano-fillers might be employed as energy dissipating elements in modern vehicles.