Aluminium matrix composites (AMCs) are renowned for their exceptional properties, including low density, high specific strength, high thermal conductivity, and abrasion resistance, making them ideal for advanced structural, automotive, and aerospace applications. However, the challenge of finding cost-effective and environmentally friendly reinforcement materials remains. Rice Husk Ash (RHA), an often-discarded by-product of rice milling, presents a viable solution. Its utilization in AMCs repurposes waste, reduces environmental impact, and offers an economically viable alternative to conventional reinforcements. This paper explores the use of RHA as a reinforcement in aluminium matrix composites, with varying concentrations of 3%, 6%, and 9% by weight prepared through sand casting. Tensile, compressive, impact, and hardness tests were conducted, and it was found that increasing the RHA content enhances the mechanical properties of the composites. Specifically, tensile strength increases by 10.57%, 16.83%, and 46.26%, and compressive strength by 17.17%, 27.81%, and 40.45% for 3%, 6%, and 9% RHA reinforcement, respectively, compared to base samples (pure aluminium). Significant improvements in Rockwell hardness and impact energy absorption were observed, with a maximum increase of 55.26% and 70.63% for the 9% RHA reinforcement. This study demonstrates the potential of RHA-reinforced AMCs to surpass the mechanical properties of pure aluminium, contributing to the circular economy by transforming rice husk waste into a valuable composite material for diverse structural applications.

This research compares the performance of structural steel and general aluminum alloys in identical crank arm designs when bearing loads are applied at different stages of paddling, such as starting, climbing, and racing. Finite element analysis (FEA) was utilized to evaluate fatigue life and safety factors. A design modification strategy was proposed to reduce critical stress in failure zones, resulting in an increased fatigue life. Although steel and aluminum alloys both have significant life and nominal high fatigue life during racing and climbing, respectively, aluminum alloys are unable to withstand a 1815 N starting load, even after modification.

This study investigates cellular negative stiffness honeycomb (NSH) structures in the prospect of energy absorption and vibration isolation. The energy absorption properties for different geometrical parameters have been investigated for a specific displacement in the range of linear compression. The force–displacement characteristics of NSH structures with various AM materials have been investigated using the finite element analysis method. The results have revealed the parametric relation of the NSH with the energy absorbed, specific energy absorption, stiffness, and compressive stress. The analysis highlights the NSH structures’ potential to enhance material efficiency and performance optimization, contributing to material and manufacturing engineering.