• Title/Summary/Keyword: 모아레

Search Result 112, Processing Time 0.026 seconds

Inverse Estimation of Viscoplastic Properties of Solder Alloy Using Moir$\acute{e}$ Interferometry and Computer Model Calibration (모아레 간섭계와 모델교정법을 이용한 솔더 합금의 점소성 물성치 역추정)

  • Gang, Jin-Hyuk;Lee, Bong-Hee;Joo, Jin-Won;Choi, Joo-Ho
    • Journal of the Computational Structural Engineering Institute of Korea
    • /
    • v.24 no.1
    • /
    • pp.97-106
    • /
    • 2011

  • In this study, viscoplastic material properties of solder alloy which is used in the electronics packages are inversely estimated. A specimen is fabricated to this end, and an experiment is conducted to examine deformation by Moir$\acute{e}$ interferometry. As a result of the experiment, bending displacement of the specimen and shear strain of the solder are obtained. A viscoplastic finite element analysis procedure is established, and the material parameters are determined to match closely with the experiments. The uncertainties which include inherent experimental error and insufficient data of experiments are addressed by using the method of computer model calibration. As a result, material parameters are identified in the form of confidence interval, and the displacements and strains using these parameters are predicted in the form the prediction interval.

  • PDF KSCI

Analysis of a Complete Contact Problem in Bonded Condition: Comparison of Experimental-Numerical Analyses and Theoretical Solutions (응착조건의 완전접촉문제 해석: 실험 및 수치해석과 이론해의 비교)

  • Kim, Hyung-Kyu;Jang, Jae-Won;Lee, Soon-Bok
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.39 no.6
    • /
    • pp.583-588
    • /
    • 2015

  • Asymptotic method has been often used to theoretically analyze the complete contact problem. The error of the asymptotic results increases as the distance from the contact edge increases. The singularity cannot be properly obtained from a finite element (FE) analysis owing to the finiteness of the element size. In the present work, the complete contact problem in bonded condition is analyzed using a combined experimental-numerical approach to assist and/or compare with the asymptotic results. Al and Cu alloys are used for the material combination of the punch and substrate. 120 and 135 degrees are used for the punch angle. The FE models are validated by comparison of displacement distributions obtained by the FE analysis and $moir{\acute{e}}$ experiment. Generalized stress intensity factors are evaluated using the validated FE models. Stress field in the vicinity of the sharp contact edges obtained from the FE and asymptotic analyses are compared. The discrepancies are also discussed.

  • https://doi.org/10.3795/KSME-A.2015.39.6.583 인용 PDF KSCI

A Vision-based Pipe Support Displacement Measurement Method Using Moire Patterns (모아레 현상을 이용한 영상기반 파이프 서포트 변위측정 방법)

  • Park, Junbeom;Park, Semi;Kim, Jaehyeon;Kim, Jungyeol
    • Korean Journal of Construction Engineering and Management
    • /
    • v.23 no.1
    • /
    • pp.37-45
    • /
    • 2022

  • It is very important to measure the displacement of a structure to evaluate the safety of the structure. This study shows a methodology to measure the displacement to determine the stability of a structure when it is damaged by loads. The methodology used Moiré's phenomenon and was verified through experiments. The experiments utilized pipes to simulate the pipe supports in the construction site and measured the vertical displacement of the Moiré interference patterns according to the horizontal displacement of the pipes. Experiments confirmed that the linear relationship between horizontal displacement of pipes and vertical displacement of Moiré patterns and derive a relational expression. In conclusion, the methodology presented in this work allows us to simultaneously measure a number of vertical members' displacements regardless of distance and determine the safety of the structure.

  • https://doi.org/10.6106/KJCEM.2022.23.1.037 인용 PDF KSCI