본 연구는 철계 형상기억합금(Fe-SMA)의 화재 후 성능과 화재 후 구조물의 성능 회복을 위한 프리스트레싱 재료로서의 적용 가능성을 평가하였다. 이를 위해 사전변형률이 2.5%, 5.0%, 7.5%인 Fe-SMA 시편을 최대 가열 온도 400°C, 500°C, 600°C, 700°C 까지 가열한 뒤 냉각 및 인장시험을 수행하였다. 가열 및 냉각 과정에서의 온도–응력 이력 분석 결과, 사전변형률이 높을수록 가열 중 좌굴이 지연되고 냉각 후 더 큰 회복응력이 발현됨을 확인하였다. 특히 7.5% 사전변형률 시편은 500°C 이상에서 500 MPa 이상의 회복응력을 보였으며, 강성 저하 시점의 응력 또한 400°C에서 793 MPa, 700°C에서 735 MPa로 세 조건 중 가장 큰 값을 나타냈다. 2.5%와 5.0% 시편은 600°C 및 700°C에서 5∼10% 더 큰 극한변형률을 나타냈으나, 7.5% 시편은 보강재로서 충분한 극한변형률을 확보함과 동시에 강성 저하 시 더 큰 응력을 유지하여 화재 후 보강재로 사용되기에 가장 적합한 것으로 판단되었다. 본 연구는 500°C 이상의 고온에 노출된 Fe-SMA의 회복응력과 기계적 특성 데이터를 제공함으로써 기존 연구의 공백을 보완하였고, Fe-SMA가 화재 후 구조물 피해 저감과 성능 회복에 기여할 수 있는 보강재로서의 잠재력을 제시하였다.

In this study, the shape of the exterior, not the inside of the product, was modified. Various exterior shape change plans were compared and reviewed through injection molding analysis, and among them, the most effective shape for suppressing warpage deformation was derived. The shape of the product was modified to optimize the bending deformation of the cover located at the top of the automobile battery case. The analysis was conducted under a total of three conditions, each of shape A, which is a rectangular parallelepiped shape at the top of the product, and shape B, which is concave on the side of the product. As a result of the study, both shape A and shape B were reduced compared to the amount of bending deformation of the original shape. Among them, shape B2, which showed the largest reduction, decreased by 82.096% from the amount of bending deformation of the original shape.

This study evaluates how road profile and speed affect tire loads of a hydrogen tube trailer using MSC Adams/Car multibody dynamics simulation. A tractor and trailer loaded with 64 high-pressure cylinders were modeled, and four representative road profiles flat, pothole, short-wave, and long-wave were applied at 30, 60, and 80 km/h. Vertical tire load time histories were extracted for five wheel positions. Flat roads yielded stable loads matching static distribution. Potholes produced short, high-amplitude impacts (up to 120 kN at 30 km/h) with reduced peaks at higher speeds. Short-wave profiles caused severe asymmetric roll loads (67 kN at 80 km/h), while long-wave inputs generated smoother, moderate increases over longer durations. Load amplification diminished toward trailer axles due to suspension energy dissipation. The results inform structural design of tube trailers and development of speed-control or active load-mitigation strategies for autonomous hydrogen transport vehicles.

본 논문은 형상기억합금으로 능동 구속된 콘크리트의 일축 압축거동을 예측하기 위한 해석적 연구이다. 일축 압축거동을 예측하기 위해 SMA로 능동 구속된 콘크리트에 대한 적합조건을 기반으로 유효 구속응력이 도출되었으며, 기존 모델에 기반한 응력-변 형률 모델을 이용하여 SMA로 능동 구속된 콘크리트의 일축 압축거동 예측 방법이 제안되었다. 제안된 모델에 대한 검증을 위해 선행 연구에 대한 실험데이터가 수집되었다. 제안 모델을 통한 예측 결과는 콘크리트의 최대 압축강도 및 최대 압축강도에 해당하는 변형률 에 대한 비를 각각 1.00 및 0.89로 예측하였으며, 콘크리트의 응력-변형률 곡선을 비교적 정확히 예측하는 것으로 나타났다.

This study implements a high-precision camshaft profile grinding system by retrofitting the C-axis and X-axis structures of an existing cylindrical grinding machine and integrating CNC variable monitoring and control functions based on the manufacturer-provided Programming Package. The original inverter-driven C-axis was replaced with a servo motor to enable precise angular positioning, while a linear scale was additionally applied to the X-axis to establish a closed-loop system capable of high-precision infeed control. Changes in the grinding wheel diameter due to dressing are compensated by real-time monitoring of internal CNC variables, enabling regeneration of the profile grinding program to prevent degradation of form accuracy. Perfomance evaluation showed that the camshaft profile accuracy was maintained within ±4 μm, and the consistency of the profile was sustained within ±2.5 μm over repeated grinding cycles. This study presents a practical technological foundation for converting cylindrical grinding machines into profile grinders capable of precision machining of non-circular components such as camshafts.

Ti-6Al-4V alloy is widely utilized in aerospace and medical sectors due to its high specific strength, corrosion resistance, and biocompatibility. However, its low machinability makes it difficult to manufacture complex-shaped products. Advancements in additive manufacturing have focused on producing high-performance, complex components using the laser powder bed fusion (LPBF) process, which is a specialized technique for customized geometries. The LPBF process exposes materials to extreme thermal conditions and rapid cooling rates, leading to residual stresses within the parts. These stresses are intensified by variations in the thermal history across regions of the component. These variations result in differences in microstructure and mechanical properties, causing distortion. Although support structure design has been researched to minimize residual stress, few studies have conducted quantitative analyses of stress variations due to different support designs. This study investigated changes in the residual stress and mechanical properties of Ti-6Al-4V alloy fabricated using LPBF, focusing on support structure design.

최근 지구온난화로 인한 피해가 심각해짐에 따라 화석연료 사용을 줄이고자 친환경 수소 에너지의 활용이 증가하고 있다. 이에 따라 수소의 저장 및 운송을 위한 수소 저장 용기의 수요가 확대되고 있으나, 현재 널리 사용되고 있는 강재 기반 저장 용기는 부식과 같은 내구성 저하 현상에 취약하다. 따라서 선행 연구는 지지부 부식에 따른 내진 성능 저하 문제를 해결하기 위해 부식 저항성 이 뛰어난 CFRP를 지지부 기둥을 적용하여 설계 하중에서 적용성을 검토하였다. 이때 본 연구는 CFRP의 강도-중량비가 높음을 고려 하여 기존 강재 구조물 지지부 ㄱ 단면 대비 높은 강성을 가진 H 단면과 ㅁ 단면을 지지부 기둥에 적용하여 연구를 수행하였다. 이때 실제와 가까운 해석 결과를 도출하기 위해 고유진동수 추출해석을 진행하여 감쇠 계수를 적용 시켰고, AC 156 인공 지진을 설계 하중 으로 적용한 결과, ㅁ 단면을 적용한 강재 기둥의 접합부 응력은 222.34 MPa로 기존 ㄱ 형강 대비 78.93%로 설계 하중에 만족함을 보였다. ㅁ 단면 적용 CFRP 기둥은 파손 지수(DI)를 통해 평가하였고, 이때 최대 DI는 수지 인장에서 발생하였으며, 그 값은 0.708로 파괴 기준 대비 29.2% 낮아 설계 하중에 만족함을 보였다. 또한, 기초 슬래브에서 쪼갬 인장 응력과 휨 인장 응력을 통한 평가를 진행 하였고, 현장 실험 결과와 마찬가지로 설계 하중에 휨 인장 파괴가 발생하는 것으로 확인하였다. 하지만 파단 시점은 CFRP에서 1.54배 오래 설계 하중에 견디는 것을 확인하여, 그 적용성을 확인하였다. 결론적으로 지진의 발생 빈도가 높아짐에 따라 수소 저장 용기의 안전성 확보가 시급하다. 따라서 기존 강재 대상 구조물의 부식으로 인한 강성 저하 문제를 해결하기 위해, 높은 내구성 및 부식 저항성 재료의 적용은 필수적이다. 동시에 기초 슬래브의 안전성 확보에 대한 연구가 추가적으로 수행되어야 한다.

The casting manufacturing process of aluminum automotive wheels often involves processing various wheel models during stages such as flow forming, machining, packaging, and delivery. Traditionally, separate equipment or production lines were required for each model, which led to higher facility investment costs and increased labor costs for classification. However, the implementation of machine learning-based model classification technology has made it possible to automatically and accurately distinguish between different wheel models, resulting in significant cost savings and enhanced production efficiency. Additionally, this approach helps prevent product mix-ups during the final inspection process and allows for the quick and precise identification of wheel models during packaging and delivery, reducing shipping errors and improving customer satisfaction. Despite these benefits, the high cost of machine learning equipment presents a challenge for small and medium-sized enterprises(SMEs) to adopt such technologies. Therefore, this paper analyzes the characteristics of existing machine learning architectures applicable to the automotive wheel manufacturing process and proposes a custom CNN(Convolutional Neural Network) that can be used efficiently and cost-effectively.

이주의 시대를 맞이하여 오늘날 한국으로 이주해 오는 이주민이 많아지고 있다. 이에 따라 이주민과 상호문화적인 의사소통을 할 수 있는 이주민 선교가 절실히 요구되고 있다. 그런데 상호문화적인 의사 소통을 위해서는, 우리와 이주민이 문화적으로 서로 다른 존재라는 점을 인식하면서도 동시에 우리와 이주민은 같은 사람으로 그리 다르지 않은 존재라는 점을 인식해야 한다. 그래서 본 소논문에서는 정주민과 이주민이 같은 사람이라는 점을 인식하는 데 도움을 주는 하나님의 형상 해석이 무엇인지 탐구해보고자 했다. 탐구 결과, 기존에 제기되었 던 하나님의 형상에 관한 해석들이 정주민과 이주민이 같은 사람이라는 점을 드러내는 데 한계를 지니고 있음을 확인하였다. 따라서, 그동안 보통 하나님의 형상으로 이해되지 못했던 ‘이주자로서의 하나님의 형상’이, 정주민과 이주민 모두 하나님 앞에서 같은 존재라는 점을 잘 드러낼 수 있다고 제안한다. 끝으로, 적절한 이주민 선교에 도움이 되기 위해서, 경계를 넘는 이주자에서 드러나는 하나님의 형상을 고려 할 것을 강력히 주장한다.

This study evaluated catch selectivity differences between sea pike (Sphyraena japonica) and Spanish mackerel (Scomberomorus niphonius) using a modified codend with square mesh side panels in bottom trawl. Sea trials were conducted with the covered codend technique widely used to estimate codend selectivity curves at the coastal sea of Yokji-do, Gyeongsangnam-do, from December 2024 to January 2025. Selectivity curves were fitted using a B-spline model for sea pike and a probit model for spanish mackerel. The estimated 50% retention lengths ( ) were 26.88 cm for sea pike and 42.92 cm for Spanish mackerel, with selection ranges () of 2.42 cm and 10.76 cm, respectively. Spanish mackerel was shown the broader and more gradual selectivity curve, while sea pike showed steeper selectivity. This study found that selectivity changes depending on the change in the net structure of the trawl tip. In addition, a difference in selectivity was observed for two species with different morphological characteristics.

In this study, the molten steel flow inside the mold according to the shape change of the submerged entry nozzle (SEN) was simulated in the continuous casting process, and the effects of the immersion depth and long side length of the mold on the molten steel flow were compared and analyzed. The heat flow analysis was performed using the ANSYS Fluent software, and the turbulence model used the standard k-ε model. Based on the analysis results, the meniscus velocity decreased with deeper immersion depth, but it was slightly faster with lower immersion depth. In addition, the flow velocity of the molten steel of the outlet was increased because the molten steel exiting the upper outlet spread directly without colliding with the short side of the mold when the long side of the mold length was increased.

In this study, static and dynamic analyses were conducted on three atypical building models to evaluate the displacement response reduction performance based on the outrigger system installation location in a atypical building that incorporated both tapered and twisted shapes. Three 60-story models were developed with a fixed 3-degree taper and twist angles of 1, 2, and 3 degrees per story. Outrigger systems were installed at 10-story intervals and additionally between the 20th and 40th floor at 1-story intervals. The results indicated that, although there were variations depending on the seismic loads, the displacement response reduction performance was generally most effective when the outriggers were installed in the upper stories (41st to 60th floors) of the analytical models.

The rotary type dust remover is a device in which the rake assembly filters and processes clumps in the water while rotating and repeating movements along the track. It is installed in the pump suction part of the drainage pump station and the rainwater pump station to protect the pump to ensure smooth drainage. Since the rake assembly plays a key role in filtering out complications while passing through the water, stainless steel is applied to all components constituting it, and damage or failure due to deformation causes a crisis in case of heavy rain. This is because the existing rake assembly is excellent in rigidity, but all components are assembled by welding, which takes a lot of time for repair and replacement. In this study, shape design for rakes and assemblies of the rotary type dust remover, structural analysis to secure reliability, and demonstration tests were conducted through prototype production. Through this, it is intended to help prevent the stiffness of the joint of the rotary type dust remover from deteriorating, reduce time and cost, and efficient operation.

Water-soluble substances like hydrogen fluoride, generated in semiconductor manufacturing, pose serious health and environmental risks, underscoring the need for effective capture devices. Vertical liquid capture devices help by aggregating and discharging hazardous substances with water, but their design can lead to backflow during abnormal operations, causing unintended releases and impacting efficiency and safety. This study seeks to improve a vertical liquid collection device’s containment performance by optimizing its geometry. The vertical wall was rotated at various angles and directions, and turbulent kinetic energy and streamline distribution were analyzed to assess vortex formation and flow characteristics. These structural modifications identify optimal conditions to control hazardous substance migration, offering insights for future pollutant removal device designs.

Structures compromised by a seismic event may be susceptible to aftershocks or subsequent occurrences within a particular duration. Considering that the shape ratios of sections, such as column shape ratio (CSR) and wall shape ratio (WSR), significantly influence the behavior of reinforced concrete (RC) piloti structures, it is essential to determine the best appropriate methodology for these structures. The seismic evaluation of piloti structures was conducted to measure seismic performance based on section shape ratios and inter-story drift ratio (IDR) standards. The diverse machine-learning models were trained and evaluated using the dataset, and the optimal model was chosen based on the performance of each model. The optimal model was employed to predict seismic performance by adjusting section shape ratios and output parameters, and a recommended approach for section shape ratios was presented. The optimal section shape ratios for the CSR range from 1.0 to 1.5, while the WSR spans from 1.5 to 3.33, regardless of the inter-story drift ratios.

In the development of a digital multi-process welding machine, we aimed to analyze the heat dissipation effects resulting from changes in the transformer's shape. Two installation configurations for the transformer, vertical and horizontal, were proposed. Thermal-flow analysis was conducted for the welding machine, taking into account variations in spacing between each proposed configuration. The results indicated that the shape and spacing of the components did not significantly alter the airflow around the reactor coil, which is the main heat-generating component of the machine. When comparing the heat dissipation effects across models with different transformer spacings, it was observed that models with narrower spacing exhibited improved heat dissipation, while the vertical configuration demonstrated a slightly higher heat dissipation effect overall. Transient analysis revealed the irregularities in internal flow and the resulting scattered temperature distribution over time within the welding machine.