In this study, an algorithm applying deep learning to the truss structures was proposed. Deep learning is a method of raising the accuracy of machine learning by creating a neural networks in a computer. Neural networks consist of input layers, hidden layers and output layers. Numerous studies have focused on the introduction of neural networks and performed under limited examples and conditions, but this study focused on two- and three-dimensional truss structures to prove the effectiveness of algorithms. and the training phase was divided into training model based on the dataset size and epochs. At these case, a specific data value was selected and the error rate was shown by comparing the actual data value with the predicted value, and the error rate decreases as the data set and the number of hidden layers increases. In consequence, it showed that it is possible to predict the result quickly and accurately without using a numerical analysis program when applying the deep learning technique to the field of structural analysis.

In this study, a numerical approach based on mid-point integrated finite elements and a viscous boundary is proposed for time-domain wave-propagation analyses in infinite poroelastic media. The proposed approach is accurate, efficient, and easy to implement in time-domain analyses. In the approach, an infinite domain is truncated at some distance. The truncated domain is represented by mid-point integrated finite elements with real element-lengths and a viscous boundary is attached to the end of the domain. Given that the dynamic behaviors of the proposed model can be expressed in terms of mass, damping, and stiffness matrices only, it can be implemented easily in the displacement-based finite-element formulation. No convolutional operations are required for time-domain calculations because the coefficient matrices are constant. The proposed numerical approach is applied to typical wave-propagation and soil-structure interaction problems. The model is verified to produce accurate and stable results. It is demonstrated that the numerical approach can be applied successfully to nonlinear soil-structure interaction problems.

In this paper, we study the existing results of the structure-soil-structure interaction (SSSI) effect on seismic responses of structures and summarize important parameters. The parameters considered in this study are a combination of buildings in the power block of a nuclear power plant, the characteristics of earthquake ground motions and its direction, and the characteristics embedded under the ground. Based on these parameters, the seismic analysis model of the structures in the power block of the nuclear power plant is developed and the structure-soil-structure interaction analyses are performed to analyze the influence of the parameters on the seismic response. For all analyses, the soil-structure interaction (SSI) analysis program CNU-KIESSI, which was developed to enable large-sized seismic analysis, is used. In addition, the SSI analyses is performed on individual structures and the results are compared with the SSSI analysis results. Finally, the influence of the parameters on the seismic response of the structure due to the SSSI effect is reviewed through comparison of the analysis results.

As a method of seismic-design for pile-supported wharves, equivalent static analysis, response spectrum analysis, and time history analysis method are applied. Among them, the response spectrum analysis is widely used to obtain the maximum response of a structure. Because the ground is not modeled in the response spectrum analysis of pile-supported wharves, the amplified input ground acceleration should be calculated by ground classification or seismic response analysis. However, it is difficult to calculate the input ground acceleration through ground classification because the pile-supported wharf is build on inclined ground, the methods to calculate the input ground acceleration proposed in the standards are different. Therefore, in this study, the dynamic centrifuge model tests and the response spectrum analysis were carried out to calculate the appropriate input ground acceleration. The pile moment in response spectrum analysis and the dynamic centrifuge model tests were compared. As a result of comparison, it was shown that the response spectrum analysis results using the amplified acceleration in the ground surface were appropriate.

경량한 세장 구조물의 내풍안정성을 향상시키기 위하여 다양한 제진장치가 사용되어 왔다. 제진장치에 의하여 구조물에 부가되는 감쇠는 기존의 질량, 강성에 비례하는 고전감쇠와 달리 비고전 특성을 가진다. 비고전 감쇠는 복소의 모달 특성을 보유하기 때문에 해석과 평가과정에서 모드의 거동을 파악하기 어렵다. 이러한 이유 때문에 복소 모달 변수를 실수로 변경하기 위한 방법이 요구 되며, 변경된 실수 모달 특성이 가지는 물리적 의미를 고찰할 필요가 있다. 본 연구에서는 상태공간에서 비고전 감쇠시스템의 복소 모달 변수를 실수 모달 변수로 변경하는 과정을 소개하고 그 모달변수가 가지는 특성을 분석함으로써 비고전 감쇠를 가지는 구조물의 해석 및 평가가 보다 명쾌한 물리적 의미를 가지고 이루어질 수 있도록 하였다. 또한 비고전 감쇠구조물의 계측응답만으로 실수의 모달 특성을 추정할 수 있는 상태공간 기반 모드분해 기법에 대해서 다루고 그 특성을 비교 검증하였다. 본 연구에서 제시된 기법을 카고메 트러스 댐퍼가 설치된 비고전 감쇠 구조물에 적용하여 수치적으로 검증하였으며, 수치해석 결과로부터 복소 모드형상이 실수공간으로의 변환이 가능하며, 그 실수 모드형상이 계측응답만으로도 추정 가능함을 알 수 있었다.

본 연구에서는 옹벽 구조물의 내진성능 평가를 위해 2차원 유한요소 해석을 수행하였다. 2차원 유한요소 모델은 실제로 시공된 옹벽 구조를 기반으로 2차원 평면변형 요소로 모델링되었으며, 지반은 각각 유한요소와 무한요소로 모델링 하였다. 지진하중은 총 38개의 인공 지진을 생성하여 사용하였고, 생성된 인공 지진파를 11개의 PGA로 나누어 총 418회의 시간이력해석을 수행하였다. 수치해석 결과를 바탕으로 옹벽 구조물의 지진에 대한 취약도를 분석하였다. 취약도 분석 결과 콘크리트 및 철근의 취약도 곡선이 낮은 PGA 수준에서 급격히 변하는 것을 관찰할 수 있었다. 유한요소 해석 결과를 바탕으로 실제 현장의 옹벽 구조에서 상대적으로 낮은 수준의 지진파가 발생하더라도 높은 파괴확률로 인해 지진에 상대적으로 취약함을 확인하였다.

본 연구에서는 DVR 내부 공기유동을 직접 제어하여 CPU의 온도를 낮추기 위한 유동제어 구조물을 제안하였다. 제안된 구조물은 세 개의 얇은 판의 형태로 구성되었으며, DVR 내부의 공기 유동을 포괄적으로 제어하여 CPU의 효율적인 방열을 유도하고자 하였다. DOE와 RSM을 이용한 매개변수 연구기법을 통해 유동제어 구조물의 형상을 최적화하였으며, 해석에는 유한체적방법을 이용한 유체역학 분석 패키지인 FlowVision을 사용하였다. 실제 DVR 기기에서의 실험을 통해 해석 결과를 검증한 결과 CPU의 온도가 16.1℃ 낮아짐을 확인하였다

Laminated composite structures have started to play a very significant role in primary and secondary structural weight savings in high performance automobile industries. However, one of the main challenges in implementing these composites is the lack of understanding of the progress of the damage under various loading conditions. In order to understand the influence of design parameters related to the use of composite materials, a proper study of the laminated composite structures requires a complete failure analysis, which includes both initiation and propagation of damage. In this study, a new damage model was developed to predict the progressive damage of the composite, and the progress of damage was investigated by making center-notch and open-hole tensile test specimens for various lay-ups. The simulations, in agreement with experimental tests, indicate that the model is capable of predicting the failure load in open hole composite structures.

This paper describes a development of design tool for knowledge based engineering(KBE) that covers structural, aerodynamic, and optical analysis of large-scale telescope structures. A module of the commercial program Adaptive Modeling Language(AML) was used to develop a knowledge-based design tool that reflects the design of parameters for rapid design change and analysis. Through this study, it is proposed a design tool with a knowledge based engineering and a function based design technique. The knowledge based engineering design is good at frequent design changes, and it is effective to extract a core design behavior from previous designs. It is concluded that the developed tool can bring fair effects in implementing a time and cost-effective design environment.

콘크리트 구조물 표면에 발생하는 균열은 사용자에게 심리적인 불안감을 제공하며, 장기간 열려있는 큰 폭의 균열은 구조 물의 사용성능 및 내구성에 영향을 준다. 국내에서는 건축물을 포함한 시설물의 노후화에 따른 안전관리를 위해 균열정도를 파악하는 조사가 인력에 의한 육안조사로 수행되고 있지만 인력의 고비용성과 객관성 미흡 등의 문제점이 대두되고 있다. 이를 해결하기 위해 영상분석을 통한 균열 추출 등 다양한 연구가 수행되고 있으나 균열인식 정확도 향상에 2차원 영상 분석만으로는 한계가 있다. 따라서, 본 연구에서는 기존 2차원 영상 분석의 한계를 극복하기 위하여 3차원 특성을 정확하게 파악할 수 있는 3차원 광삼각 스캐닝기법을 활용하여 콘크리트 구조물 표면의 균열정보를 획득하는 기법을 개발하였다. 본 하 드웨어의 개발과 더불어 균열 패턴분석을 위한 획득된 균열의 세분화와 균열의 특성분석 알고리즘을 개발하였으며, 이를 실제 콘크리트 빔의 균열 탐지 적용을 통해 검증하였다.

본 논문에서는 이단계 칼만필터를 활용한 구조물의 3 자유도 동적변위 계측 시스템을 소개한다. 개발 시스템은 센서 모듈, 베이스 모듈, 컴퓨테이션 모듈로 구성되어 있다. 센서 모듈은 100Hz 샘플주파수의 고정밀 가속도를 계측하는 포스피드백 가 속도계와 10Hz의 샘플주파수의 저정밀도의 속도, 변위를 계측하는 저가의 RTK-GNSS로 구성되어 있다. 계측된 데이터는 LAN 케이블을 통하여 컴퓨테이션 모듈로 전송되고, 컴퓨테이션 모듈에서 이단계 칼만필터를 활용하여 100Hz 샘플주파수의 고정밀 변위를 실시간으로 산정한다. 개발 시스템의 변위 계측 정밀도를 검증하기 위해 미국, 캘리포니아에 위치한 San Francisco-Oaklmand Bay bridge 에서 현장 실험을 수행하였으며, 실험 결과 1.68mm RMS 오차를 보임을 확인하였다.

In this study, TMD(Tuned Mass Damper) is installed in a retractable-roof spatial structure in order to investigate dynamic response characteristics according to mass ratio and installed position of TMD on large spatial structures. The example analytical model is generated based on the Singapore sports hub stadium. Twenty eight analytical models are used to investigate optimal installation position of TMD for the example retractable-roof spatial structure using 4 to 16 TMDs. The mass of one TMD is set up 1% of total mass at the example analytical model. Displacement response ratio of model with TMD is compared with that of base model without TMD. It has been found from numerical simulation that it is more effective to install TMD at the edge of the spatial structure rather than to concentrate the TMD at the center of the spatial structure.

The purpose of this study was to develop a carbon fiber sheet with embedded fiber optic sensor for maintenance and performance improvement of aged concrete bridges. The carbon fiber sheet reinforcement method can separate the concrete and the carbon fiber sheet, so it is necessary to investigate the bond performance level. However, separation of concrete and carbon fiber sheet and investigation of concrete scaling phenomenon are carried out by human, so it is difficult to secure objectivity and accurate investigation. Therefore, in this study, a method to confirm the bond level of carbon fiber sheet by reinforcing with a carbon fiber sheet with a fiber optic sensor was examined. In this study, we investigated the strain of fiber optic sensor embedded in carbon fiber sheet to identify the separate point of carbon fiber sheet. The strain measured by fiber optic sensor was measured by numerical analysis. The strain rate of the carbon fiber sheet was compared with that of the carbon fiber sheet. As a result, it was confirmed that the strain was changed at the point where the carbon fiber sheet was separated, and the strain occurred in the carbon fiber sheet was examined to predict the separate point.

Recently, damage to domestic facilities due to strong winds and typhoons is increasing. This study focused on sign structures among various vulnerable facilities. The evaluation of wind fragility was performed considering the destruction of the anchor for fixing, which is one of the failure modes of the sign structures. The performance evaluation of the anchor for fixing was carried out to derive the wind fragility. Three parameters were set and twelve anchor types were selected to perform the pull-out and shear tests. The resistance performance was estimated based on the experimental results. Wind loads were estimated using the Monte Carlo simulation method. Based on this, we derive the wind fragility according to the wind exposure category. Finally, the change of the wind exposure category and the evaluation of the wind fragility according to the experimental parameter were performed.

In this study, the fragility for transmission tower subjected to wind disaster, which has the greatest influence on transmission tower, was developed for 154kV transmission tower located between Yangyang and Sokcho city. The resistance capacity and the limit state required for the evaluation of the fragility were divided into the major part and the auxiliary part in the steel tower. Moreover, the failure of tower was defined as the yielding stress of each member in the tower which could be used to determine their resistance performance. Domestic wind design guideline and criteria for transmission tower was used to determine the wind loads demand on the tower. By comparing the loading demand and resistance capacity, the failure of tower could be determined which in turn used to derive the wind fragility. The results obtained in this study could be used as a reference for damage prediction system of transmission tower and similar structures.

The improvement in computing systems and sensor technologies devotes to conduct data-driven structural health monitoring algorithms for existing civil infrastructures. Despite of the development of techniques, the uncertainty oriented from the measurement results in the discrepancy to the actual structural parameters and let engineers or decision makers hesitate to adopt such techniques. Many studies have shown that the modal identification results can be affected by the uncertainties due to the applied methods and the types of loading. This paper aims to compare the performance of modal identification methods using Structural Modal Identification Toolsuite (SMIT) which has been developed to facilitate multiple identification methods with a user-friendly designed platform. The data fed into SMIT processes three stages for the comprehensive identification including preprocessing, eigenvalue estimation, and post-processing. The seismic and white noise response for shear frame model was obtained from numerical simulation. The identified modal parameters is compared to the actual modal parameters. In order to improve the quality of coherence in identified modal parameters, several hurdles including modal phase collinearity and extended modal amplitude coherence were introduced. Numerical simulation conducted on the 5 dof shear frame model were used to validate the effectiveness of using these parameters.