This study outlines a structural design process for a cylindrical superelastic shape memory alloy (SMA) ligation clip. Although polymer-based clips are widely used, they face challenges related to long-term stability and limited radiopacity, highlighting the necessity for metal clips. By systematically modifying two key design variables—the hole offset ratio and the cut-off ratio—the proposed clip effectively reduces excessive stress concentration and enhances superelastic behavior. Finite element analyses indicate that the stress deviation in the two cross-sectional deformation regions decreased by 83.9%, and the martensitic transformation remained confined to a small area, demonstrating robust strain recovery within the superelastic range. In conclusion, the improved SMA clip successfully withstood internal pressures exceeding 15 psi without leakage, showcasing its superior ligation performance and potential for durable, reliable use in minimally invasive surgical procedures.

This study details the development of a semi-active suspension wheel module for small mobile robots and assesses its dynamic characteristics under various driving conditions through simulation. The wheel module features a low-degree-of-freedom mechanical design and includes a semi-active damper to improve adaptability to different environments. To validate the simulation model, a prototype robot equipped with the wheel module was created, and obstacle-crossing experiments were conducted to measure vertical acceleration responses. The model was then refined based on these experimental results. By employing design of experiments and optimization techniques, the effective range of damping coefficients was estimated. Additionally, simulations were carried out at different speeds, payloads, and obstacle heights to identify optimal damping values and examine their trends. The results indicate that the proposed module significantly enhances driving stability and can serve as a foundation for future control strategies in robotic mobility systems.

This study presents a dual-impeller air-cooled heat exchanger aimed at improving thermal management in electro-optical tracking systems operating under high power density. Two geometric modifications were introduced to enhance flow characteristics and heat transfer performance: the curvature of the center plate and the integration of a pin-fin structure at the outlet. Through numerical simulation, the improved model demonstrated more efficient internal flow compared to the original model, achieved through enhanced inflow characteristics and reduced flow separation. The pin-fin structures induced localized turbulence and recirculation zones, contributing to an increased thermal exchange surface area and longer effective heat transfer time. Consequently, the outlet temperature of the internal system decreased by an average of 1.4°C across various rotational speeds, resulting in a 5.9% increase in heat exchanger efficiency compared to the original model. Overall, this study shows that structural enhancements in heat exchanger design can significantly improve the cooling performance of high-power electronic systems, suggesting practical applicability for advanced thermal management solutions.

The rise of electric vehicles (EVs) has led to a reduction in engine noise, making suspension and road noise more noticeable. However, most assessments focus only on air-conducted (AC) pathways and overlook bone-conducted (BC) transmission. This study identifies key sources of vehicle noise and implements a finite-element simulation to replicate real-world driving conditions. A 12-degree-of-freedom (DOF) human body model quantifies how vibrations transmit from the vehicle structure to the head. Additionally, a detailed finite-element model of the human head evaluates basilar-membrane (BM) vibrations for both AC and BC inputs. The results indicate that BC dominates below 10 Hz, producing BM velocities up to 50 dB greater than AC. Above 10 Hz, AC prevails, showing a difference of approximately 40 dB. Notably, at frequencies of 33, 46, 67, and 80 Hz, the AC–BC difference narrows to below 10 dB, highlighting significant BC effects even at higher frequencies. These findings reveal that neglecting bone-conduction pathways can lead to an underestimation of occupant exposure to low-frequency vibrations. Therefore, comprehensive evaluations and control methods for vehicle noise should consider both AC and BC transmission mechanisms to accurately reflect human perception