External stores on low-speed rotorcraft are subjected to various external forces depending on the aircraft's operating conditions. While there are different types of external forces, this paper focuses on flight loads as defined by US defense specifications. Flight loads consist of static and dynamic loads. Static loads on aircraft external stores include inertial loads resulting from aircraft maneuvers and aerodynamic loads caused by the downward flow of the main wing. To define the inertial load, the inertial load factor on external stores was calculated, while the minimum analysis case for aerodynamic load was derived from trim analysis of rotorcraft blades. The critical design load diagram was developed by combining these factors, and ANSYS was utilized to analyze the structural robustness under static loads. Based on the characteristics of the main wing, a finite element analysis was conducted using a vibration profile tailored to the actual operating environment and an impact profile suitable for the impact conditions. Structural robustness was further assessed through actual tests. This analysis provides essential data for airworthiness certification, allowing for the safe installation of external stores on low-speed rotorcraft.

With the increasing frequency of laparoscopic surgery, interest in the application of polymeric ligation clips as a method for ligating blood vessels has grown. Automatic clip appliers with built-in polymeric ligation clips have been developed to reduce ligation time. As the built-in clip is loaded into the jaw of the applier for ligation, a high spring constant, the elastic property of the clip is required to load properly. As the built-in clip loses its elastic properties due to stress relaxation over time, a polymeric ligation clip with a high spring constant is needed to increase the shelf life of the applier. In this study, four design factors of the cavity at the clip hinge (length, width, eccentricity, and angle of the cavity) were derived and applied to the Taguchi optimization method using finite element analysis to evaluate which factor was critical. The four design factors explained 93.5% of the variation in the spring constant. The factors related to cavity width and eccentricity were significant at p<0.05. Cavity width was the most crucial factor, explaining 70.8% of the variation in the spring constant. The spring constant of the improved clip model increased by 55.4% compared with the existing model.

Metal additive manufacturing using electron beam melting (EBM) process applies electron beam for heating, sintering, and melting of powders to fabricate a three-dimensional component. The component may contain residual porosity internally and may be subjected to poor surface finish externally. To improve the quality of the surface finish and densification, re-melting is conducted. The purpose of this paper was to estimate the appropriate process conditions for a plasma electron beam remelting process using heat transfer finite element analyses (FEAs). The impact of the travel speed of table and thickness of the deposited part on temperature distributions were examined. The size of molten pool was estimated from the results of the thermal FEA. From the estimated size of molten pool, the travel speed of table and the hatch spacing between remelting tracks are discussed and selected as the appropriate process conditions for electron beam re-melting process from the perspective of minimum overlapping region of the molten pool.

Fluid Catalytic Cracking (FCC) Unit is a large-pressure vessel that converts heavy crude oil, which cannot be distilled, into light crude oil. With the growing interest in renewable energy sources due to environmental regulations, various studies investigating FCC Units are ongoing. The catalytic reactor in FCC Unit is a large structure that generates prolonged high pressure, leading to changes in the properties of the material during operation. Therefore, stress analysis must be conducted based on the application of the actual mechanical properties. In cylindrical thin structures such as the FCC reactor, a tensile test is difficult to perform, warranting the need for Shear Punch (SP) test that uses a small specimen. The properties were utilized in finite element analysis. To determine the boundary and load conditions needed for stress analysis, the operational conditions of the reactor and the conditions for internal pressure of ASME Code regulation were used to evaluate the stress.