For estimating ground motion intensity measures on the surface from seismic sensors installed in structures, it is crucial to correct structural response effects embedded in the recorded signals. This study proposes a model for peak ground acceleration (PGA) amplification based on VS30, derived from multi-degree-of-freedom analysis. PGA amplification factor (AFPGA) is defined as the ratio of peak floor acceleration (PFA) of structures to PGA. The model includes three key input parameters: the natural period of the structures (Tn), the ratio of stories to the total number of stories in the structures, and the time-averaged shear wave velocity down to a depth of 30 meters. It is developed using 78 ground motion records from both domestic and international earthquakes. A LOESS smoothing technique is applied using 3 span values, with the optimal span of 0.1 is determined based on RMSE performance and an analysis of local trend characteristics in the dataset. The model is verified using empirical data from the CESMD global strong motion database, which includes classification by Tn into short, intermediate, and long periods. The results show that although the model tends to predict higher AFPGA values than those observed in real structures, it effectively reflects the overall amplification trends. This approach enables the pre-earthquake estimation of structural amplification, allowing for the use of seismic sensors installed in structures as a complementary monitoring network for seismic response.

This study analyzed the structural performance of a microalgae-based lightweight ecological integration system for large-span structures to achieve carbon neutrality. To address the load problems of existing soil-based ecological systems, a lightweight system utilizing microalgae bioreactors was proposed, and structural performance was evaluated for four types of large-span structures: truss, arch, dome, and cable structures. Structural analysis results through finite element analysis showed that the proposed system achieved a 70% load reduction effect compared to existing systems, with structural performance improvements including 35-40% reduction in maximum deflection, 30-35% reduction in maximum stress, and 25-30% increase in natural frequency. Environmental performance analysis confirmed CO₂absorption capacity of 12-18 kg per m² annually and PM2.5 reduction effects of 15-25%. Economic analysis results indicated that benefits of 3.95-6.7 million KRW per year are generated for a 1,000 m²reference area, creating cumulative benefits of 179.75-227.5 million KRW over 25 years. Verification through the German BIQ House case confirmed CO₂reduction performance of 6 tons per year for 200 m², demonstrating the practical applicability of the system. This study presented the potential of an innovative ecological integration system that can ensure structural safety of large-span structures while simultaneously contributing to carbon neutrality.

This study was intended to compare with seismic fragility assessments for a low-rise RC piloti structure using the Capacity Spectrum Method (CSM) and the Incremental Dynamic Analysis (IDA). Distribution-parameters were estimated using the Method of Moments (MoM) and the Maximum Likelihood Estimation (MLE). For given limit states defined by FEMA 356, two seismic fragility assessments yielded different medians and dispersions: the CSM produced steeper in the slopes of fragility curves with smaller dispersions, whereas the IDA captured wider response scatters and broader dispersions. When fitting the fragility curves, the MLE scheme provided to well match with the empirical cumulative distribution function(CDF) than the MoM scheme, which understated dispersions.

Machine learning (ML) techniques have been increasingly applied to the field of structural engineering for the prediction of complex dynamic responses of safety-critical infrastructures such as nuclear power plant (NPP) structures. However, the development of ML-based prediction models requires a large amount of training data, which is computationally expensive to generate using traditional finite element method (FEM) time history analysis, especially for aging NPP structures. To address this issue, this study investigates the effectiveness of synthetic data generated using Conditional Tabular GAN (CTGAN) in training ML models for seismic response prediction of an NPP auxiliary building. To overcome the high computational cost of data generation, synthetic tabular data was generated using CTGAN and its quality was evaluated in terms of distribution similarity (Shape) and feature relationship consistency (Pair Trends) with the original FEM data. Four training datasets with varying proportions of synthetic data were constructed and used to train neural network models. The predictive accuracy of the models was assessed using a separate test set composed only of original FEM data. The results showed that models trained with up to 50% synthetic data maintained high prediction accuracy, comparable to those trained with only original data. These findings indicate that CTGAN-generated data can effectively supplement training datasets and reduce the computational burden in ML model development for seismic response prediction of NPP structures.

The K2 tank not only has excellent mobility but also has excellent protection performance. Armor steel is used to provide structural protection, and the turret structure is made of rolled homogeneous armor (RHA) plates. Most processes for fabricating structures involve welding, but RHA steel has the problem of being susceptible to thermal deformation. To compensate for this, a plan to apply the bending method was considered. In this study, prior to applying the bending method to an actual vehicle, mechanical property evaluations were performed on materials, welding, and bending specimens. It has been proven that the bending method can achieve performance equivalent to or better than the welding method. The verification tests included hardness tests, tensile tests, fatigue tests, and impact tests. All tests except the impact test confirmed that the bending method was superior to the welding method. In the case of the impact test, the impact value of the bending method was lower, but it satisfied the standard with a value higher than the minimum requirement according to the standard, so it is judged that there will be no problem in applying the bending method.

The purpose of this paper is to investigate the vibration phenomenon occurring in the structure such as a ship with the hemispherical substructure and operating at fixed frequency, and to suggest the active vibration control method using the Fx-LMS algorithm to reduce vibration amplification. In order to study the possibility of reducing vibration in the hemispherical structure, the active vibration control model was developed and a vibration control experimental device for the hemispherical structure was constructed. The narrowband Fx-LMS algorithm was developed to enable precise real-time control at a specific frequency, and the secondary path for dynamic control was modeled with two coefficients per frequency. The experimental device is equipped with three exciters, six 3-axis actuators, and six 3-axis error sensors, which can acquire 18 error sensor signals. Real-time secondary path tracking was possible with the secondary path consisting of two coefficients and the control algorithm, and effective vibration control performance was confirmed through this. And the experimental results of active vibration control of the exciter for three frequencies showed that the exciter vibration was reduced by a minimum of 63.7% and a maximum of 97.7%, which shows the possibility of reducing the vibration of the structure in real time using the proposed method.

In this study, in order to identify the vibration characteristics of the process control cabinet, as a basic study for evaluating the seismic performance of nuclear power plant structures, a cabinet vibration test equipment, sliding base, and measurement system were constructed. The reliability of the base was verified by utilizing ODS and phase data to determine how the cabinet deforms under seismic conditions. In addition, the cabinet was subjected to excitation frequencies from 8 Hz to 15 Hz in order to examine the changes in the natural frequency of the cabinet according to the two types of sliding base motion and the cabinet door open/close status. The vibration characteristics of the empty cabinet were investigated experimentally to examine the cabinet excitation characteristics and changes in natural frequency. Since the structural rigidity of the cabinet changes depending on the excitation conditions and door opening/closing, the natural frequency and response size of the cabinet change. Since the door opening is a condition that greatly amplifies the cabinet vibration response, it causes structural defects and greatly affects the changes in natural frequency.

This study examines the effects of additive manufacturing (AM) orientations and support structures on the compressive strength of lattice structures. Test specimens were fabricated using a selective laser melting (SLM) process with AlSi10Mg material under three conditions: horizontally aligned (0°), tilted at 45°, and supported. Compression tests were conducted using a universal testing machine (UTM) and Digital Image Correlation (DIC) to evaluate mechanical behavior. The results showed that the supported horizontal specimens exhibited the highest compressive strength, while the 45° tilted specimens had the lowest due to interlayer separation and localized failures. The findings highlight the significance of build orientation and support design in optimizing AM lattice structures. Future research should explore various lattice configurations, material selections, and post-processing effects to further enhance structural performance.

본 논문은 미국의 초현실주의 아상블라주 작가로 알려진 조셉 코넬의 초기 작업인 1930-1940년대에 병행했던 두 형식인 상자 구조물 아상블라주와 필름 콜라주에 주목하여 다양한 기술 매체를 통해 시청각적 감각을 확장한 예술적인 시도를 살펴본다. 그리고 이 시기 코넬의 매체 혼성적인 실험의 내재적인 동력으로서 뇌성마비로 인해 신체적·언어적 제약을 가졌던 동생 로버트 코넬과 함께 지낸 경험에 주목한다. 코넬에게 로버트는 돌봄의 대상에 그치지 않고 오히려 사회적인 관습과 성인의 타성을 벗어나게 하는 타자적인 존재이자 그의 감각적인 실험 의 원동력이었다. 코넬은 인간과 자연의 움직임을 기계적으로 산출한 원초적인 시각 매체에 관심을 가지고 쉐도우박스, 원시적 광학 장치, 무성 영화와 같은 과거의 매체를 인간의 지각과 감각을 확장하는 장치로서 긍정적으로 수용했다. 코넬의 상자 구조물과 필름 콜라주는 거동이 불편한 로버트가 감각적 유희를 즐기면서도 신체적인 제약을 넘어 열린 시공간의 세계를 상상할 수 있도록 하였다. 로버트와 보낸 시간의 기 억을 담고 있는 그의 필름 콜라주는 분절적으로 누적된 시간과 다층적으로 중첩된 감정을 담은 비선형적인 심연의 시간을 다룬 독자적인 실험 이었다.

본 연구에서는 구조물의 응답 데이터를 기반으로 고유진동수, 감쇠비 등 동특성과 풍하중 모델의 파라미터를 동시에 추정할 수 있는 스펙트럼 백색화 기반 식별 기법을 제안하고, 이를 실제 40층 고층 구조물에 적용하여 실용성과 정확도를 평가하였다. 기존 연 구에서는 본 기법을 수치 시뮬레이션 및 풍동 실험에 적용하여 그 타당성을 입증한 바 있으나, 실계측 응답 데이터를 활용한 실구조물 적용에 대해서는 검증이 이루어지지 않았다. 본 연구는 이를 확장하여, 장기간 계측된 고층 건축물의 진동 응답을 분석하고, 각 주요 모드에 대해 백색화 처리를 수행함으로써 구조물 전달함수 및 풍하중 전달함수의 파라미터를 최적화 기반으로 동시 추정하였다. 특히 백색 잡음의 누적 파워 스펙트럼 길이를 목적함수로 설정함으로써, 기존 커브 피팅 기반 기법 대비 감쇠비 추정의 정확도와 안정성을 향상시켰다. 분석 결과는 전통적인 모달 식별 기법(예: SSI)과의 비교를 통해 제안 기법의 유효성을 입증하였으며, 풍하중 모델 파라미 터까지 포함하는 통합적 구조 해석 프레임워크로서의 가능성을 제시하였다. 본 연구는 향후 구조물의 풍응답 예측, 하중 생성 모델 구 축, 구조 건전도모니터링(SHM) 및 디지털 트윈 기반 해석 등 다양한 실무 응용에 기여할 수 있을 것으로 기대된다.

In this study, a response model of a beam structure was established through finite element analysis by analyzing the vibration response to external excitation. The vibration control performance of the beam was then evaluated by applying the narrow-band Fx-LMS algorithm for active structural control. The transfer function was obtained at the error sensor location when the structure was excited and the three-axis actuator was operated. The performance of the active control was investigated with 18 channels for error input and actuator output. When the equipment is exciting, the response of the error sensor is the primary path, and when the inertial 3-axis actuator operates, the response of the error sensor position is the secondary path, and the Fx-LMS algorithm is applied. The simulation was performed by changing the control parameters so that the response of the error sensor can satisfy the target performance. From the results of this study, the acceleration results over time showed about 70% vibration reduction after active control, and the average error value of the error sensor also decreased by about 68%. In addition, it was confirmed that real-time control of a system with 18 sensors and 18 actuators is possible even if the secondary path is configured in two orders.

본 연구에서는 지반-구조물 상호작용(SSI, Soil-Structure Interaction) 해석에서 계산 효율성과 해석 정확성을 동시에 확보하기 위해 철근 콘크리트 기둥의 단순 모델링 기법과 PML(Perfectly Matched Layer) 요소를 결합한 방법을 제안하였다. 단순 모델링 기법은 상 세모델과 비교하였을 때 강성 및 고유진동수 차이가 1% 이내로 나타나 구조물의 정적 및 동적 거동을 효과적으로 모사할 수 있음을 확인하였다. PML 요소를 적용한 SSI 해석은 반무한지반 모델 대비 계산 영역을 1/5로 줄이고, 해석 시간을 7% 수준으로 단축하면서 도 기둥의 고유진동수가 동일하게 나타났다. 이를 통해 PML 요소가 계산 비용을 대폭 줄이면서도 해석 결과의 정확성을 유지할 수 있음을 확인하였다.

Damage to masonry walls can occur for various factors. It is often believed that heavy rains and increased rainfall cause soil and sand to flow into the stone masonry walls, leading to this damage. However, no research has definitively proven or analyzed this causal relationship.This study aims to evaluate the causes of damage to masonry walls due to severe rainfall and to propose preventive strategies to mitigate future risks. The assessment found that, as a form of cultural heritage, the stone masonry walls did not exhibit any structural or material issues that could compromise their stability. However, concerns were raised about potential problems arising from hydraulic pressure due to rising groundwater levels. Calculations and computer simulations confirmed that the risk of collapse increases with higher groundwater levels. Therefore, it is essential to carry out repairs and reinforcements to prevent a recurrence of this situation.

By developing molds and facilities to horizontally mold the functional part of the dry-cast concrete block, We intend to develop molds and a series of facilities to horizontally mold the functional part of the dry-cast concrete block to increase production per cycle while maintaining existing production methods and major facilities. In order to do so, CAE analysis is first required to develop molds and facilities for horizontally molding the functional part of the drycast concrete block in the horizontal direction. The procedure will be carried out by reviewing the validity of boundary conditions and physical properties, 3D modeling, grid generation, construction of analysis models, model validity, analysis according to frequency changes, and analysis according to physical properties. First, through the comparison of two-point support, three-point support, and two-point and three-point support in the constraint conditions, We would like to compare it with the actual molded product in the horizontal direction.