• Title/Summary/Keyword: Inverse analysis method

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A Field Case Research by Construction Management of Underground Excavation Construction Using Inverse Analysis Method (역해석 기법을 이용한 지하굴착공사의 시공관리에 관한 현장사례연구)

  • Park, Hyun-Jung
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.15 no.2
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    • pp.1089-1095
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    • 2014
  • In this study, we compared and analyzed the displacement of final excavation with measured value through an inverse analysis method used in urban excavation construction. We maximized the effectiveness of the inverse analysis method, and plan to achieve cost-effective and practical construction management in the field with identical conditions. As the first stage, we suggest an example of a field which has the inverse analysis method. We applied the inverse analysis method to three different fields on which construction and measuring were finished. Of these three fields, two fields showed a very satisfactory result. However, in one field, there were significant differences between the analysis and measured value. The result of our analysis indicated that, we should unite the conditions of the inverse analysis method and field construction. We need to thoughtfully reconsider the RANKINE earth pressure application in a triangle type. This is because the uniformity of earth pressure is made by its arching effect, in the condition of the displacement of lower underground occurring widely, which is differentiated with the earth pressure conditions of RANKINE, even if the slurry wall has stiffness. Also, when recalculating the soil parameter, we should emphasize the adhesion of the weathering zone, and give experimental consideration to ground water level.

Crack Identification Using Neuro-Fuzzy-Evolutionary Technique

  • Shim, Mun-Bo;Suh, Myung-Won
    • Journal of Mechanical Science and Technology
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    • v.16 no.4
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    • pp.454-467
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    • 2002
  • It has been established that a crack has an important effect on the dynamic behavior of a structure. This effect depends mainly on the location and depth of the crack. Toidentifythelocation and depth of a crack in a structure, a method is presented in this paper which uses neuro-fuzzy-evolutionary technique, that is, Adaptive-Network-based Fuzzy Inference System (ANFIS) solved via hybrid learning algorithm (the back-propagation gradient descent and the least-squares method) and Continuous Evolutionary Algorithms (CEAs) solving sir ale objective optimization problems with a continuous function and continuous search space efficiently are unified. With this ANFIS and CEAs, it is possible to formulate the inverse problem. ANFIS is used to obtain the input(the location and depth of a crack) - output(the structural Eigenfrequencies) relation of the structural system. CEAs are used to identify the crack location and depth by minimizing the difference from the measured frequencies. We have tried this new idea on beam structures and the results are promising.

Crack Identification Using Optimization Technique (수학적 최적화기법을 이용한 결함인식 연구)

  • Seo, Myeong-Won;Yu, Jun-Mo
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.24 no.1 s.173
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    • pp.190-195
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    • 2000
  • It has been established that a crack has an important effect on the dynamic behavior of a structure. This effect depends mainly on the location and depth of the crack. To identify the location and depth of a crack in a structure. Nikolakopoulos et. al. used the intersection point of the superposed contours that correspond to the eigenfrequency caused by the crack presence. However the intersecting point of the superposed contours is not only difficult to find but also incorrect to calculate. A method is presented in this paper which uses optimization technique for the location and depth of the crack. The basic idea is to find parameters which use the structural eigenfrequencies on crack depth and location and optimization algorithm. With finite element model of the structure to calculate eigenfrequencies, it is possible to formulate the inverse problem in optimization format. Method of optimization is augmented lagrange multiplier method and search direction method is BFGS variable metric method and one dimensional search method is polynomial interpolation.

Crack Identification Based on Synthetic Artificial Intelligent Technique (통합적 인공지능 기법을 이용한 결함인식)

  • Sim, Mun-Bo;Seo, Myeong-Won
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.25 no.12
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    • pp.2062-2069
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    • 2001
  • It has been established that a crack has an important effect on the dynamic behavior of a structure. This effect depends mainly on the location and depth of the crack. To identify the location and depth of a crack in a structure, a method is presented in this paper which uses synthetic artificial intelligent technique, that is, Adaptive-Network-based Fuzzy Inference System(ANFIS) solved via hybrid learning algorithm(the back-propagation gradient descent and the least-squares method) are used to learn the input(the location and depth of a crack)-output(the structural eigenfrequencies) relation of the structural system. With this ANFIS and a continuous evolutionary algorithm(CEA), it is possible to formulate the inverse problem. CEAs based on genetic algorithms work efficiently for continuous search space optimization problems like a parameter identification problem. With this ANFIS, CEAs are used to identify the crack location and depth minimizing the difference from the measured frequencies. We have tried this new idea on a simple beam structure and the results are promising.

Crack identification based on synthetic artificial intelligent technique (통합적 인공지능 기법을 이용한 결함인식)

  • Shim, Mun-Bo;Suh, Myung-Won
    • Proceedings of the KSME Conference
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    • 2001.06c
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    • pp.182-188
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    • 2001
  • It has been established that a crack has an important effect on the dynamic behavior of a structure. This effect depends mainly on the location and depth of the crack. To identify the location and depth of a crack in a structure, a method is presented in this paper which uses synthetic artificial intelligent technique, that is, Adaptive-Network-based Fuzzy Inference System(ANFIS) solved via hybrid learning algorithm(the back-propagation gradient descent and the least-squares method) are used to learn the input(the location and depth of a crack)-output(the structural eigenfrequencies) relation of the structural system. With this ANFIS and a continuous evolutionary algorithm(CEA), it is possible to formulate the inverse problem. CEAs based on genetic algorithms work efficiently for continuous search space optimization problems like a parameter identification problem. With this ANFIS, CEAs are used to identify the crack location and depth minimizing the difference from the measured frequencies. We have tried this new idea on a simple beam structure and the results are promising.

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Detection of a Crack in Beams by Eigen Value Analysis (고유치 해석을 이용한 보의 크랙 탐색)

  • Lee, Hee-Su;Lee, Ki-Hoon;Cho, Jae-Hoon
    • Proceeding of EDISON Challenge
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    • 2016.03a
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    • pp.195-202
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    • 2016
  • In this paper, crack detection method using eigen value analysis is presented. Three methods are used: theoretical analysis, finite element method with the cracked beam elements and finite element method with three dimensional continuum elements. Finite element formulation of the cracked beam element is introduced. Additional term about stress intensity factor based on fracture mechanics theory is added to flexibility matrix of original beam to model the crack. As using calculated stiffness matrix of cracked beam element and mass matrix, natural frequencies are calculated by eigen value analysis. In the case of using continuum elements, the natural frequencies could be calculated by using EDISON CASAD solver. Several cases of crack are simulated to obtain natural frequencies corresponding the crack. The surface of natural frequency is plotted as changing with crack location and depth. Inverse analysis method is used to find crack location and depth from the natural frequencies of experimental data, which are referred by another papers. Predicted results are similar with the true crack location and depth.

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Crack Identification Using Evolutionary Algorithms in Parallel Computing Environment (병렬 환경하의 진화 이론을 이용한 결함인식)

  • Sim, Mun-Bo;Seo, Myeong-Won
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.26 no.9
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    • pp.1806-1813
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    • 2002
  • It is well known that a crack has an important effect on the dynamic behavior of a structure. This effect depends mainly on the location and depth of the crack. To identify the location and depth of a crack in a structure, a classical optimization technique was adopted by previous researchers. That technique overcame the difficulty of finding the intersection point of the superposed contours that correspond to the eigenfrequency caused by the crack presence. However, it is hard to select a trial solution initially for optimization because the defined objective function is heavily multimodal. A method is presented in this paper, which uses continuous evolutionary algorithms(CEAs). CEAs are effective for solving inverse problems and implemented on PC clusters to shorten calculation time. With finite element model of the structure to calculate eigenfrequencies, it is possible to formulate the inverse problem in optimization format. CEAs are used to identify the crack location and depth minimizing the difference from the measured frequencies. We have tried this new idea on a simple beam structure and the results are promising with high parallel efficiency over about 94%.

Identification of isotropic and orthotropic constitutive parameters by FEA-free energy-based inverse characterization method

  • Shang, Shen;Yun, Gun Jin;Kunchum, Shilpa;Carletta, Joan
    • Structural Engineering and Mechanics
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    • v.45 no.4
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    • pp.471-494
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    • 2013
  • In this paper, identification of isotropic and orthotropic linear elastic material constitutive parameters has been demonstrated by a FEA-free energy-based inverse analysis method. An important feature of the proposed method is that it requires no finite element (FE) simulation of the tested material. Full-field displacements calculated using digital image correlation (DIC) are used to compute DIC stress fields enforcing the equilibrium condition and DIC strain fields using interpolation functions. Boundary tractions and displacements are implicitly recast into an objective function that measures the energy residual of external work and internal elastic strain energy. The energy conservation principle states that the residual should be zero, and so minimizing this objective function inversely identifies the constitutive parameters. Synthetic data from simulated testing of isotropic materials and orthotropic composite materials under 2D plane stress conditions are used for verification of the proposed method. When identifying the constitutive parameters, it is beneficial to apply loadings in multiple directions, and in ways that create non-uniform stress distributions. The sensitivity of the parameter identification method to noise in both the measured full-field DIC displacements and loadings has been investigated.

Feasibility Test for Hydraulic Conductivity Characterization of Small Basin-Scale Aquifers Based on Geostatistical Evolution Strategy Using Naturally Imposed Hydraulic Stress (자연 수리자극을 이용한 소유역 규모 대수층 수리전도도 특성화: 지구통계 진화전략 역산해석 기법의 적용 가능성 시험)

  • Park, Eungyu
    • Journal of Soil and Groundwater Environment
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    • v.25 no.4
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    • pp.87-97
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    • 2020
  • In this study, the applicability of the geostatistical evolution strategy as an inverse analysis method of estimating hydraulic properties of small-scale basin was tested. The geostatistical evolution strategy is a type of data assimilation method that can effectively estimate aquifer hydraulic conductivity by combining a global optimization model of the evolution strategy and a local optimization model of the ensemble Kalman filtering. In the applicability test, the geometry, hydraulic boundary conditions, and the distribution of groundwater monitoring wells of Hanlim-Eup were employed. On the other hand, a synthetic hydraulic conductivity distribution was generated and used as the reference property for ease of estimation quality assessment. In the estimations, two different cases were tested where, in Case I, both groundwater levels and hydraulic conductivity measurements were assumed to be available, and only the groundwater levels were available, in Case II. In both cases, the reference and estimated hydraulic conductivity fields were found to show reasonable similarity, even though the prior information for estimation was not accurate. The ability to estimate hydraulic conductivity without accurate prior information suggests that this method can be used effectively to estimate mathematical properties in real-world cases, many of which little prior information is available for the aquifer conditions.

Estimation of Coefficient of Horizontal Subgrade Reaction by the Inverse Analysis on the Lateral Load Test Results (수평재하시험 역해석을 통한 수평지반반력계수 산정)

  • Ryu, Soo-Yong;Kwak, No-Kyung;Park, Min-Chul;Jeong, Sang-Guk;Lee, Song
    • Journal of the Korean GEO-environmental Society
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    • v.13 no.8
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    • pp.15-24
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    • 2012
  • Even though decision of coefficient of horizontal subgrade reaction is important in analysis for pile under lateral load, the behavior of pile under lateral loading is estimated differently due to using established suggestion. Therefore this study estimates coefficient of horizontal subgrade reaction by using Chang's method or numerical inverse analysis method with the result of lateral load test. Then this study investigates the adequacy and reliability for coefficient of horizontal subgrade reaction. The analytical results of coefficient of horizontal subgrade reaction with lateral load test showed that coefficient of horizontal subgrade reaction with Chang's method was underestimated as compared with inverse analysis. Deformation modulus of foundation by Standard Specifications for Highway Bridges and Eo${\fallingdotseq}$1,400~1,600N showed similar range like range of coefficient of horizontal subgrade reaction with lateral load test.