Polymer composites have opened a novel innovation phase in additive manufacturing (AM), and now lightweight, high-strength, and geometrical advanced components with tailored functionalities can be produced. The present study introduces advances in polymer composite materials and their integration into AM processes, particularly in rapidly growing industries such as aerospace, automotive, biomedical, and electronics. The embedding of cutting-edge reinforcement materials, such as nanoparticles, carbon fibers, and natural fibers, into polymer matrices enhances mechanical, thermal, electrical, and multifunctional properties. These material developments are combined with advanced fabrication techniques, including multi-material printing, in situ curing, and functionally graded manufacturing, which achieves accurate regulation of microstructures and properties. Furthermore, high-impact innovations such as smart polymer composites with self-healing or stimuli-responsive behaviors, the growing shift toward sustainable, bio-based composite alternatives, are driving progress. Despite significant advances, challenges remain in interfacial bonding, printability, process repeatability, and long-term durability. This review offers a comprehensive overview of current advancements and outlines future directions in polymer composite–based AM.

Bicycles are popular mode of transportation around the world. The frame is an important part of a bicycle, which comprises various parts including the top tube, bottom tube, seat tube, chain stay, seat stay, and head tube. The commonly used bicycle frame is diamond shaped. Extensive research has been conducted on the overall frame of different shaped sports bicycle using different materials. However, there are opportunities to conduct detailed research on individual frame tubes under a variety of load conditions. Such investigations could provide deeper insights into the stress distribution, deformation characteristics, and failure mechanisms of each tube. Using finite element analysis, this paper investigates the comparative behavior of each tube of a diamond-shaped bicycle frame using three different materials: Steel, Aluminum 6061-T6 and Titanium alloy. Three load conditions - static start up, horizontal load and vertical load are considered for the analysis. This analysis examines the stresses, that occur within the bicycle frame tubes and indicate that, steel tubes show superior performance in handling both stress and deformation comparing to aluminum and titanium tubes. The analysis reveals that, steel tubes exhibit approximately 65% less deformation compared to aluminum tubes and 51% less deformation compared to titanium tubes. Among the frame components, the seat stay, seat tube, and top tube experience the highest levels of deformation for all load cases. Also, the results show that, strain energy is highest in steel tubes, while aluminum tubes exhibit the lowest strain energy.