Friction Welding (FRW) is a solid-state welding method. This technology also permits the connecting of dissimilar and similar materials while consuming less electricity than conventional electric welding. Friction welding is frequently used to join a variety of components because it generates high-quality joints and is capable of joining a wide range of materials and their complexity. This research examined the friction welding of stainless steel and pure zinc. The investigation concentrated on the welding parameters, specifically the effect of friction time and provision of preheating on parameters with high joint strength, as well as the mechanical properties, microstructure, and characterization of the joint material. The results of the experimental research indicated that the welding settings had a significant impact on the friction welding process. The tensile strength increased as a result of the reduced friction duration during the welding process, as demonstrated by the experimental findings. The longer the friction period, the more an oxide layer will form on the surface of the metal, preventing the diffusion process and impacting the production of the intermetallic phase for the joint’s strength.

The effect of inertial friction welding and continuous drive friction welding in joining SS 316 with Zn alloy is discussed in this article. Scanning electron microscopy was utilized to investigate the microstructure of the welding interaction. Energy-dispersive spectroscopy was utilized to identify the chemical composition of the element distribution at the interface. The findings reveal that a continuous drive friction welding process may produce SS 316 welded joints with Zn alloy. With a friction time of 35 s, the joint's tensile strength may reach 60 MPa. During the tensile test , all friction-welded samples failed at the interface. The fracture surface shows an almost flat surface and is not fibrous or brittle. Meanwhile, a new reaction layer from the intermetallic compound layer is not formed at the joint interface . The decrease in hardness in Zn alloys is due to the thermal softening effect caused by continuous heat from friction.

The phenomenon of crack branching is one of the typical fracture behaviours. The effect of crack branching orientation is investigated in this paper. By considering a static branched crack in a 2D plate under uniaxial traction, the numerical study is carried out for two study cases. The first study case is the symmetric crack branching in which the various crack branching length and orientation have the same value between both crack branching. The second case is the asymmetric case crack branching. In this case, both crack branching length has a particular constant value, Moreover, the orientation of first crack branching is constant and then the second one has various values. The stress intensity factors of the crack tips are calculated for both study cases. It is revealed for the symmetric case; the increasing of the crack branching length will increase the value of stress intensity factors K_I for various orientations of crack branching. In contrast, the stress intensity factors K_I will tend to decrease along with the increasing of the crack branching orientation. Moreover, the stress intensity factors K_I of first crack branching will increase, but the stress intensity factors K_I of second crack branching will decrease along with increasing of the second orientation crack branching for the asymmetric case. Furthermore, the direction the stress intensity factors K_II will prone to change along with the increasing of the crack branching orientation. The stress intensity factor K_II tends to increase along with the increasing of the crack branching orientation as well as the increasing of the crack branching length for the symmetric case. And then the increase of constant angle of first crack branching will increase significantly the stress intensity factors K_II of the first crack tip along with the increasing of the second crack branching angle for the asymmetric case.

This study explores the sound absorption behavior of polyurethane-based composites reinforced with nanocellulose derived from oil palm empty fruit bunches. Nanocellulose was synthesized through chemical and mechanical processes and incorporated into the polyurethane matrix at weight ratios of 3%, 5%, 10%, and 20%. Test specimens were prepared with standardized dimensions and evaluated using a four-microphone impedance tube system following ASTM E2611-19 to determine the frequency-dependent acoustic response across the 125–5000 Hz range. The results demonstrated a clear improvement in sound absorption in the mid-to-high frequency bands (1000–4000 Hz) as nanocellulose content increased, with peak absorption coefficients (α) exceeding 0.7 at frequencies above 3000 Hz for 5% and 10% formulations. This enhancement is attributed to increased tortuosity, airflow resistivity, and complex internal structures formed by the nanocellulose fibers. However, performance in the low-frequency range (100–1000 Hz) remained limited across all compositions, and excessive filler loading (20%) led to diminishing returns due to particle agglomeration and reduced pore connectivity. These findings suggest that oil palm empty fruit bunch nanocellulose holds substantial potential as a sustainable acoustic reinforcement material, particularly for high-frequency applications. Further structural optimization is recommended to expand its applicability for broadband noise control.