• Title/Summary/Keyword: 3-D displacement

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Estimation of Displacements Using Artificial Intelligence Considering Spatial Correlation of Structural Shape (구조형상 공간상관을 고려한 인공지능 기반 변위 추정)

  • Seung-Hun Shin;Ji-Young Kim;Jong-Yeol Woo;Dae-Gun Kim;Tae-Seok Jin
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.36 no.1
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    • pp.1-7
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    • 2023
  • An artificial intelligence (AI) method based on image deep learning is proposed to predict the entire displacement shape of a structure using the feature of partial displacements. The performance of the method was investigated through a structural test of a steel frame. An image-to-image regression (I2IR) training method was developed based on the U-Net layer for image recognition. In the I2IR method, the U-Net is modified to generate images of entire displacement shapes when images of partial displacement shapes of structures are input to the AI network. Furthermore, the training of displacements combined with the location feature was developed so that nodal displacement values with corresponding nodal coordinates could be used in AI training. The proposed training methods can consider correlations between nodal displacements in 3D space, and the accuracy of displacement predictions is improved compared with artificial neural network training methods. Displacements of the steel frame were predicted during the structural tests using the proposed methods and compared with 3D scanning data of displacement shapes. The results show that the proposed AI prediction properly follows the measured displacements using 3D scanning.

Cogging Torque Analysis of BLDC Motor with the Axial Displacement of Rotor (축방향 변위를 가진 BLDC 전동개의 코깅토크 해석에 관한 연구)

  • Kim, Young-Kyoun;Lee, Jeong-Jong;Nam, Hyuk;Hong, Jung-Pyo;Jin, Young-Woo;Hur, Yoon
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.52 no.8
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    • pp.368-372
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    • 2003
  • This paper deals with the cogging torque analysis of a BLDC Motor, which has the axial displacement of its rotor. In order to improve the torque performance of the BLDC motor, Brushless motor is commonly designed to minimize its cogging torque. Therefore, a skewed model is used to reduce the cogging torque. However, even though the rotor or stator is skewed, the cogging torque could be increased by the axial displacement of the rotor, which occurs when the BLDC Motor is manufactured. Therefore, this paper investigates the effect of the axial displacement of the rotor on the cogging torque. In order to investigate the effect, an analysis method, which is 3D-EMCN in combination with 2D-FEM, is proposed to analyze the cogging torque of the BLDC motor with the axial displacement of its rotor, and the result of the analysis is verified by comparison with the experimental result.

Study on the Thermal Deformation of the Air-conditioner Indoor Unit Assembly Using 3D Measurement and Finite Element Analysis (에어컨 실내기 사출 조립품의 열 변형 3D측정과 유한요소해석)

  • Hong, Seokmoo;Hwang, Jihoon;Kim, Cheulgon;Eom, Seong-uk
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.24 no.2
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    • pp.251-255
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    • 2015
  • Thermal deformation, such as bending and twisting, occurs among the polymer parts of air-conditioner indoor units because of repetitive temperature change during heating operation. In this study, a numerical method employing finite-element analysis to efficiently simulate the thermal deformation of an assembly is proposed. Firstly, the displacement of an actual assembly produced by thermal deformation was measured using a 3D optical measurement system. The measurement results indicated a general downward sag of the assembly, and the maximum displacement value was approximately 1 mm. The temperature distribution was measured using a thermographic camera, and the results were used as initial-temperature boundary conditions to perform temperature-displacement analysis. The simulation results agreed well with the measured data. To reduce the thermal deformation, the stiffness increased 100%. As the results, the maximum displacement decreased by approximately 5.4% and the twisting deformation of the holder improved significantly.

Manufacturing Experiments using FDM 3D-printed Flexible Resistance Sensors with Heterogeneous Polymer Material Annealing (이종 폴리머재료 어닐링을 이용한 유연저항센서 FDM 3D프린팅 제작실험)

  • Lee, Sun Kon;Oh, Young Chan;Kim, Joo Hyung
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.19 no.1
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    • pp.81-88
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    • 2020
  • In this paper, the performances of the electrical characteristics of the Fused Deposition Modeling (FDM) 3D-printed flexible resistance sensor was evaluated. The FDM 3D printing flexible resistive sensor is composed of flexible-material thermoplastic polyurethane and a conductive PLA (carbon black conductive polylactic acid) polymer. While 3D printing, polymer filaments heat up quickly before being extruded and cooled down quickly. Polymers have poor thermal conductivity so the heating and cooling causes unevenness, which then results in internal stress on the printed parts due to the rapidity of the heating and cooling. Electrical resistance measurements show that the 3D-printed flexible sensor is unstable due to internal stress, so the 3D-printed flexible sensor resistance curve does not match the increases and decreases in the displacement curve. Therefore, annealing was performed to eliminate the mismatch between electrical resistance and displacement. Annealing eliminates residual stress on the sensor, so the electrical resistance of the sensor increases and decreases in proportion to displacement. Additionally, the resistance is lowered in comparison to before annealing. The results of this study will be very useful for the fabrication of various devices that employ 3D-printed flexible sensor that have multiple degrees of freedom and are not limited by size and shape.

A 2D hybrid stress element for improved prediction of the out-of-plane fields using Fourier expansion

  • Feng, M.L.;Dhanasekar, M.;Xiao, Q.Z.
    • Structural Engineering and Mechanics
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    • v.13 no.5
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    • pp.491-504
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    • 2002
  • Recently we formulated a 2D hybrid stress element from the 3D Hellinger-Reissner principle for the analysis of thick bodies that are symmetric to the thickness direction. Polynomials have typically been used for all the displacement and stress fields. Although the element predicted the dominant stress and all displacement fields accurately, its prediction of the out-of-plane shear stresses was affected by the very high order terms used in the polynomials. This paper describes an improved formulation of the 2D element using Fourier series expansion for the out-of-plane displacement and stress fields. Numerical results illustrate that its predictions have markedly improved.

Accuracy Analysis of Close-Range Digital Photogrammetry for Measuring Displacement about Loading to Structure (하중에 따른 구조물 변위계측을 위한 근접수치사진측량의 정확도 분석)

  • Choi, Hyun;Ahn, Chang Hwan
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.29 no.4D
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    • pp.545-553
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    • 2009
  • This paper describes the result of study on measurement of displacement of structure by means of non-contacting method, close-range digital photogrammetry using digital camera. To apply close-range digital photogrammetry to displacement measurement of structure, correction of lens distortion that interferes geometrical analysis has been carried out and then measuring displacement was performed on load regulated-rahmen. For enhanced applicability of displacement measurement, MIDAS which is a structural analysis program was used for modeling and the result was taken from comparative analysis. As a result of the study, it is showed that close-range digital photogrammetry could supplement several weaknesses of LVDT and cable displacement meter and, especially, economy in the perspective of measuring time could be realized. Close-range digital photogrammetry using digital camera can be applied to the area where requires visual analysis such as 3D modeling of structure, profile replication of measurement of structure as well as measurement of displacement of structure.

Displacement-based Seismic Assessment and Rehabilitation of Asymmetric Wall Structures (비대칭 벽식 구조지 변위기초 내진성능평가 및 보강)

  • Hong, Sung-Gul;Ha, Tae-Hyu
    • Journal of the Earthquake Engineering Society of Korea
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    • v.9 no.3 s.43
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    • pp.23-32
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    • 2005
  • Torsional behavior of eccentric structure under seismic leading may cause the stress and/or deformation concentration, which arouse the failure of the structure in an unexpected manner. This study suggests D-R relationship which shows the overall displacement and rotation of the system based on the ultimate displacement capacity of the each lateral load resistant member. Using the suggested D-R relationship and displacement spectrum, the seismic assessment is conducted and verified in comparison with the time history analysis result. Multi-level seismic assessment Is considered which takes multiple seismic hazard levels and respective performance levels into account. Finally, based on the seismic assessment result, seismic rehabilitation process is presented. In this research, two rehabilitation methods are considered. One is done by means of stiffening/strengthening the seismic resistant members, and the other is based on the member ductility. Especially, in the first method, to optimize the rehabilitation result, the rehabilitation problem is modeled as an optimization problem, and solved using BFGS quasi-Newton optimization method.

Design and analysis of isolation effectiveness for three-dimensional base-seismic isolation of nuclear island building

  • Zhu, Xiuyun;Lin, Gao;Pan, Rong;Li, Jianbo
    • Nuclear Engineering and Technology
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    • v.54 no.1
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    • pp.374-385
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    • 2022
  • In order to investigate the application of 3D base-seismic isolation system in nuclear power plants (NPPs), comprehensive analysis of constitution and design theory for 3-dimensional combined isolation bearing (3D-CIB) was presented and derived. Four different vertical stiffness of 3D-CIB was designed to isolate the nuclear island (NI) building. This paper aimed at investigating the isolation effectiveness of 3D-CIB through modal analysis and dynamic time-history analysis. Numerical results in terms of dynamic response of 3D-CIB, relative displacement response, acceleration and floor response spectra (FRS) of the superstructure were compared to validate the reliability of 3D-CIB in mitigating seismic response. The results showed that 3D-CIB can significantly attenuate the horizontal acceleration response, and a fair amount of the vertical acceleration response reduction of the upper structure was still observed. 3D-CIB plays a significant role in reducing the horizontal and vertical FRS, the vertical FRS basically do not vary with the floor height. The smaller the vertical stiffness of 3D-CIB is, the better the vertical isolation effectiveness is, whereas, it will increase the displacement and the rocking effect of superstructure. Although the advantage of 3D-CIB is that the vertical stiffness can be flexibly adjusted, it should be designed by properly accounting for the balance between the isolation effectiveness and displacement control including rocking effect. The results of this study can provide the technical basis and guidance for the application of 3D-CIB to engineering structure.

Structural member stiffness influence on vertical earthquake behaviour of mid-rise R/C frame buildings in Turkey

  • Selcuk Bas
    • Computers and Concrete
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    • v.33 no.6
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    • pp.689-706
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    • 2024
  • This study is aimed at identifying structural element stiffness influence on vertical earthquake response of mid-rise R/C frame buildings. To this aim, a mid-rise RC building structure is designed as per the new Turkish Seismic Code for Buildings-2018, and 3D FE model of the building is established. Based on the established FE model, a total number of six buildings are considered depending on certain percentage increase in beam, slab, and column. The time-history response analyses (THA) are performed separately for only horizontal (H) and horizontal +vertical (H+V) earthquake motions to make a comparison between the load cases. The analysis results are presented comparatively in terms of the monitoring parameters of the base overturning moment (Mo), the top-story lateral displacement (dL) and the top-story vertical displacement (dV). The obtained results reveal that the base overturning moment and the top-story vertical displacement are affected by vertical earthquake motion regardless of the increase in the dimension of beam, slab, and column. However, vertical earthquake motion is not effective on the top-story lateral displacement due to no change between H and H+V load. The dimensional increase in either slab or beam leads to a considerable increase in the base overturning moment and the top-story vertical displacement while causing decrease in the top-story lateral displacement. In addition, the dimensional increase in column has a positive effect on the decrease in the monitoring parameters of the base overturning moment (Mo), the top-story lateral displacement (dL) and the top-story vertical displacement (dV).

Study on Bandwidth Frequency of Servovalve based on Metering Cylinder (실린더를 이용한 서보 밸브 대역폭 주파수의 측정에 관한 연구)

  • Kim, S.D.;An, Wen-Long;Jeon, S.H.
    • Journal of Drive and Control
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    • v.12 no.3
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    • pp.44-51
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    • 2015
  • In this study, a metering cylinder was constructed, and the velocity obtained from the linear velocity transducer (LVT) of the cylinder piston was used to evaluate the dynamic performance of an electro-hydraulic servovalve. Frequency response experiments involving the spool displacement and piston velocity (LVT signal) were conducted with different input signal amplitudes, hydraulic pipe diameters, and supply pressures. The spool displacement signal accurately reflected the performance of the servovalve. Meanwhile, the -3 dB bandwidth frequency of the LVT signal was similar to the spool displacement signal, except for a small-amplitude input signal, and the $-90^{\circ}$ phase lag bandwidth frequency showed some differences.