• Title/Summary/Keyword: Structural parameter

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Experimental Study for Modal Parameter Estimation of Structural Systems (구조물의 자유진동특성 추정을 위한 실험적 연구)

  • 윤정방;이형진
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1994.10a
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    • pp.175-182
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    • 1994
  • As for the safety evaluation of existing large-scale structures, methods for estimation of the structural and dynamic properties are studied. Sequential prediction error method in time domain and improved FRF estimator in frequency domain are comparatively studied. For this purpose, impact tests of 2 bay 3 floor steel frame structure are performed. Results from both methods are found to be consistent to each others, however those from the finite-element analysis are slightly different from experimental results.

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Semiparametric Bayesian Estimation under Structural Measurement Error Model

  • Hwang, Jin-Seub;Kim, Dal-Ho
    • Communications for Statistical Applications and Methods
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    • v.17 no.4
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    • pp.551-560
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    • 2010
  • This paper considers a Bayesian approach to modeling a flexible regression function under structural measurement error model. The regression function is modeled based on semiparametric regression with penalized splines. Model fitting and parameter estimation are carried out in a hierarchical Bayesian framework using Markov chain Monte Carlo methodology. Their performances are compared with those of the estimators under structural measurement error model without a semiparametric component.

An Evaluation of Clamping Characteristics for High Strength Bolts with Variable Bolt Lengths (고력볼트 길이에 따른 체결 특성 평가)

  • Lee, Kang Min;Kim, Kang Seok;Nah, Hwan Seon;Lee, Hyeon Ju;Oh, Kyung Hwan
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.15 no.6
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    • pp.127-134
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    • 2011
  • It has been reported that the length parameter of high strength bolts results in the variance in tensile loads. The required turn of nut for each length is specified in AISC RCSC specification. There is no specific regulation datum about the bolt length in the two national codes and specifications in Korea. Therefore this study focused on evaluating influence of the clamping torque subjected to length parameter of high strength bolts. Two types of high strength bolt specimens were manufactured and tested; High Strength Hexagon bolt specified in ASTM A490 and Torque Shear Bolt in KS B 2819. The length parameter ranged from 60mm(3d) to 140mm(7d). The torque, turn of nut, and the clamping force were analyzed to review whether length parameter affects on the required tensile strength. To evaluate the effects of the length parameter on the torque and turn of nut for the required strength and clamping force, statistical analysis was also carried out.

Estimation of System Damping Parameter Using Wavelet Transform (웨이블릿 변환에 의한 시스템 감쇠변수 평가)

  • Lee, Seok-Min;Jung, Beom-Seok;Hong, Seok-Woo
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.19 no.5
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    • pp.30-37
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    • 2015
  • The estimation of system damping parameter of the response signal with lower natural frequency and higher damping parameter from free vibration is affected by the wavelet center frequency. This study discusses these considerations in the context of the wavelet's multi-resolution character and includes guidelines for selection of wavelet center frequency. The experiment with H-Beam and numerical examples with respect to three cases (i)single mode, (ii)separated modes and (iii)close modes demonstrate the validity of method to improve the accuracy of the estimated damping parameter. The localization of the corresponding scale for the total scales is determined by the natural frequency of the analysing mode and is affected by the wavelet center frequency. Thus, the reliability for the accuracy of the estimated damping parameter can be improved by the corresponding scale of the natural frequency for the analysing mode is localized at the half of the total scales.

Evaluation of Ultimate Pressure Capacity of Light Water Reactor Containment Considering Aging of Materials (재료의 경년상태를 고려한 경수로형 격납건물의 극한내압능력 평가)

  • Lee, Sang-Kuen;Song, Young-Chul;Han, Sang-Hoon;Kwon, Yong-Gil
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.5 no.2
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    • pp.147-154
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    • 2001
  • The prestressed concrete containment is one of the most important structures in nuclear power plants, which is required to prevent release of radioactive or hazardous effluents to the environment even in the case of a severe accident. Numerical analyses are carried out by using the ABAQUS finite element program to assess the ultimate pressure capacity of the Y prestressed concrete containment with light water reactor at design criteria condition and aging condition considering varied properties of time-dependant materials respectively. From the results, it is verified that the structural capacity of the Y prestressed concrete containment building under the present, aging condition is still robust. In addition, the parameter studies for the reduction of the ultimate pressure capacity of containment building according to the degradation levels of the main structural materials are carried out. The results show that when the degradations of each materials are considered as individual and combined forms, the influence is large in the order of tendon, rebar and concrete degradation, and tendon-rebar, tendon-concrete and rebar-concrete degradation respectively.

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A predictor-corrector algorithm of the generalized-$\alpha$ method for analysis of structural dynamics (동적해석을 위한 일반화된$\alpha$ 방범의 예측 수정자 알고리즘)

  • ;Hulbert, Gregory M.
    • Journal of KSNVE
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    • v.5 no.2
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    • pp.207-213
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    • 1995
  • A new predictor-corrector explicit time integration algorithm is presented for solving structural dynamics problems. The basis of the algorithm is the implicit generalized-.alpha. method recently developed by the authors. Like its implicit parent, the explicit generalized-$\alpha$ method is a one- parameter family of algorithms in which the parameter defines the high-frequency numerical dissipation. The algorithm can be utilized effectively for linear and nonlinear structural dynamics calculations is which numerical dissipation is needed to reduce spurious oscillations inherent in non-dissipative time integration methods used to solve wave propagation problems.

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Prism Compressive Strength of Non-structural Concrete Brick Masonry Walls According to Workmanship (시공정밀도에 따른 비구조용 콘크리트벽돌 조적벽체의 프리즘 압축강도)

  • Shin, Dong-Hyeon;Kim, Hyung-Joon
    • Journal of the Architectural Institute of Korea Structure & Construction
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    • v.36 no.2
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    • pp.127-136
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    • 2020
  • Prism compressive strength is the most influential parameter to evaluate the seismic performance of non-structural concrete brick masonry walls, and is affected by the practice and workmanship of masonry workers. This study experimentally investigates the influence of workmanship on prism compressive strength throughout the compressive test with prism specimens constructed according to masonry workmanship. To do this, the workmanship is categorized into good, fair, and poor conditions which are statistically evaluated with thickness and indentation depth of bed-joints. Then, the effect of workmanship on the structural properties of masonry prisms is evaluated by investigating relations between properties such as their compressive strength, elastic modulus and numerical parameters such as thickness, filling of bed-joints. This study demonstrates that the indentation depth is more important parameter for structural properties of masonry prisms and masonry prisms with loss in bed-joint area less than of 7% can be in fair condition.

Modal parameter identification of civil structures using symplectic geometry mode decomposition

  • Feng Hu;Lunhai Zhi;Zhixiang Hu;Bo Chen
    • Wind and Structures
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    • v.36 no.1
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    • pp.61-73
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    • 2023
  • In this article, a novel structural modal parameters identification methodology is developed to determine the natural frequencies and damping ratios of civil structures based on the symplectic geometry mode decomposition (SGMD) approach. The SGMD approach is a new decomposition algorithm that can decompose the complex response signals with better decomposition performance and robustness. The novel method firstly decomposes the measured structural vibration response signals into individual mode components using the SGMD approach. The natural excitation technique (NExT) method is then used to obtain the free vibration response of each individual mode component. Finally, modal natural frequencies and damping ratios are identified using the direct interpolating (DI) method and a curve fitting function. The effectiveness of the proposed method is demonstrated based on numerical simulation and field measurement. The structural modal parameters are identified utilizing the simulated non-stationary responses of a frame structure and the field measured non-stationary responses of a supertall building during a typhoon. The results demonstrate that the developed method can identify the natural frequencies and damping ratios of civil structures efficiently and accurately.