• Structural Engineering and Mechanics
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• 제76권4호
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• pp.435-449
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• 2020

This work presents the formulation of the isogeometric collocation method to solve the strong form equation of a unified and integrated approach of Reissner Mindlin plate theory (UI-RM). In this plate theory model, the total displacement is expressed in terms of bending and shear displacements. Rotations, curvatures, and shear strains are represented as the first, the second, and the third derivatives of the bending displacement, respectively. The proposed formulation is free from shear locking in the Kirchhoff limit and is equally applicable to thin and thick plates. The displacement field is approximated using the B-splines functions, and the strong form equation of the fourth-order is solved using the collocation approach. The convergence properties and accuracy are demonstrated with square plate problems of thin and thick plates with different boundary conditions. Two approaches are used for convergence tests, e.g., increasing the polynomial degree (NELT = 1×1 with p = 4, 5, 6, 7) and increasing the number of element (NELT = 1×1, 2×2, 3×3, 4×4 with p = 4) with the number of control variable (NCV) is used as a comparable equivalent variable. Compared with DKMQ element of a 64×64 mesh as the reference for all L/h, the problem analysis with isogeometric collocation on UI-RM plate theory exhibits satisfying results.

• 동력기계공학회지
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• 제19권2호
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• pp.22-26
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• 2015

The main objective of this work is to estimate the fluid flow of a proportional valve. The study is based on the classical compressible flow theory and the computations with the help of CFD based commercial software - ANSYS CFX. The fluid flow with the movement of spool along the sleeve is simulated. To change the spool moving from 0.4mm to 2.0mm, the moving mesh method with different condition of orifice is considered here. The results show that it is the highest at the 80 % (1.6mm) opening and at the 20 % (0.4mm) opening, is the lowest.

• Structural Engineering and Mechanics
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• 제36권5호
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• pp.625-642
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• 2010

The Integrated Force Method (IFM) is a novel matrix formulation developed for analyzing the civil, mechanical and aerospace engineering structures. In this method all independent/internal forces are treated as unknown variables which are calculated by simultaneously imposing equations of equilibrium and compatibility conditions. This paper presents a new 12-node serendipity quadrilateral plate bending element MQP12 for the analysis of thin and thick plate problems using IFM. The Mindlin-Reissner plate theory has been employed in the formulation which accounts the effect of shear deformation. The performance of this new element with respect to accuracy and convergence is studied by analyzing many standard benchmark plate bending problems. The results of the new element MQP12 are compared with those of displacement-based 12-node plate bending elements available in the literature. The results are also compared with exact solutions. The new element MQP12 is free from shear locking and performs excellent for both thin and moderately thick plate bending situations.

• Nuclear Engineering and Technology
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• 제55권7호
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• pp.2642-2649
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• 2023

A real-time unmeasured dynamic response prediction process for the nuclear power plant pressure pipeline is proposed and its performance is tested in the test-loop system (KAERI). The aim of the process is to predict unmeasurable or unreachable dynamic responses such as acceleration, velocity, and displacement by using a limited amount of directly measured physical responses. It is achieved by combining a well-constructed finite element model and robust inverse force identification algorithm. The pressure pipeline system is described by using the displacement-pressure vibro-acoustic formulation to consider fully filled liquid effect inside the pipeline structure. A robust multiphysics modal projection technique is employed for the real-time sensor synchronized prediction. The inverse force identification method is also derived and employed by using Bathe's time integration method to identify the full-field responses of the target system from the modal domain computation. To validate the performance of the proposed process, an experimental test is extensively performed on the nuclear power plant pressure pipeline test-loop under operation conditions. The results show that the proposed identification process could well estimate the unmeasured acceleration in both frequency and time domain faster than 32,768 samples per sec.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2022년도 가을 학술논문 발표대회
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• pp.43-44
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• 2022

Recently, there is a demand for a fast and efficient method for measuring displacement during construction or maintenance of new buildings. As the number of safety accidents caused by structural collapse increases, the integrated management plan of the measurement and management system has become a platform and data is shared with stakeholders, so that it is possible to establish safety management in advance according to the displacement of the structure.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 22-24 Oct. 1991
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• pp.528-532
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• 1991

Having very small linear displacement, piezoelectric actuators have been restricted in robotic application as positioning devices. In this paper, a mechanical amplifier was developed to enhance the displacement of piezoelectric actuator and the corresponding driving circuit was designed. This equipment was integrated as a robotic wrist having 2 D.O.F micropositioning capability. Each joint was analysed in mechanical and dynamic view points. Experimental result showed that this device has Some hysteresis but could be used as vibratory robotic wrist with relatively high frequency. For more fine positioning control, a closed loop approach must be taken into account.

• 소음진동
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• 제11권1호
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• pp.36-40
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• 2001

In this paper, an integrated system for dynamic analysis and optimal design of engine mount systems is presented. The system can simulate static and dynamic behaviors of engine mount systems and optimize design parameters such as mount stiffness, mounting locations with desired design targets of frequency or displacement. A FF-engine with an automatic transmission is used to demonstrate the analysis and optimal design capabilities of the proposed design system.

• 한국정밀공학회지
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• 제16권2호통권95호
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• pp.74-81
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• 1999

The integrated chip of optical micro-encoder was fabricated and the feasibility as displacement measurement device was confirmed. The geometry of micro-encoder was designed to utilize the optical interference effect on the second order of diffracted beams. The hybrid-type micro-encoder consisted with light emitting diode, photodiode, polyimide wave-guide and micro-lens provides stable micro-encoding results for high speed displacements. The measurement shows the resolution of displacement of 1.00 +/- 0.02 ${\mu}m$ for the grating with scale pitch of 2.0${\mu}m$.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2022년도 봄 학술논문 발표대회
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• pp.135-136
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• 2022

As a recent technology, it is possible to partially grasp the occurrence of displacement of the entire building through artificial intelligence technology for big data through scanning. However, scanning and data processing take a lot of time, so there is a limit to constant monitoring, so constant monitoring technology of building behavior that combines wireless remote sensors and 3D shape scanning is required. Therefore, in this study, artificial intelligence program coding technology is linked. In addition, a technology capable of real-time wireless remote measurement of structure displacement will be developed through technology development in response to safety management that combines existing building technologies such as sensors. Through this, it is possible to establish an integrated management system for safety inspection and diagnosis.

• 한국전산구조공학회논문집
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• 제16권4호
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• pp.345-351
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• 2003

자동차 산업에서 안전에 대한 법적인 요구 및 시장 수요의 증가에 따라 강도와 경량화라는 안전과 환경에 대한 상반된 목적을 만족시켜야 하기 때문에 일체형 시트의 설계는 점점 더 중요성이 부각되고 있다. 본 연구에서는 미국시험규정 FMVSS210에 따라 외연적 유한 요소해석 프로그램인 LS-Dyna를 사용하여 시트 충돌해석을 수행하였다 하지만 충돌해석은 많은 해석시간을 요구하기 때문에 효율적이고 신뢰성 있는 최적설계기법이 요구된다. 따라서 통계적 기법인 실험계획법과 반응표면모델을 적용하여 많은 해석시간을 요구하는 LS-Dyna해석을 가능한 줄이고 비선형 최적설계 알고리즘을 적용하여 강도와 경량화를 동시에 최적화하고자 한다. 본 연구에서는 실험계획법을 사용하여 최대 변위 및 총중량에 대한 설계영역을 탐색하고 반응표면모델을 구성하여 최적설계를 수행하였다.