• 대한기계학회논문집A
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• 제27권9호
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• pp.1477-1485
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• 2003

The displacement vector field can be represented in terms of a scalar potential ${\phi}$ and a vector potential ${\phi}$. The scalar potential ${\phi}$ is related to dilatational waves and the vector potential ${\phi}$ is related to rotational waves. Using these two complex displacement potentials, the stress and displacement fields for steadily growing interface cracks in dissimilar materials are obtained. The energy release rate for steadily growing interface cracks in dissimilar materials are also obtained. And with photoelastic isochromatic patterns simulated by computer graphics, the stress intensity factors are discussed.

• 한국기계기술학회지
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• 제20권6호
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• pp.901-905
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• 2018

The objective of this study is to investigate the effect of torque variation on stress distributions in A-IMS module with both side tubular shaft yoke by numerically. In order to achieve this, the torque value was increased from 10Nm to 40Nm, and the results of this work were confirmed in terms of Von-mises Stress and the displacement characteristics. As the torque in module assembly was increased, the stress in tubular shaft york and splined shaft york was increased linearly. The indentation due to the steel ball was occurred in over $40N{\cdot}m$ torque which is over the yield strength condition. The largest displacement occurred in the tubular shaft yoke 1, however, it does not exceed the yield strength and is supposed to be restored due to the elasticity. Therefore, it was concluded that there is no problem for the manufacturing of A-IMS with both side tubular shaft yoke.

• 대한기계학회논문집A
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• 제25권8호
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• pp.1235-1241
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• 2001

An engineering estimation equation for the crack opening displacement(COD) is proposed for a complex cracked pipe, based on the reference stress approach. To define the reference stress, a simple plastic limit load analysis for the complex cracked pipe subjected to combined bending and tension is performed considering the crack closure effect in the compressive-stressed region. Comparison with ten published test data and the results from existing method shows that the present method not only reduces non-conservatism associated with the existing method, but also provides consistent and overall satisfactory results.

• Wind and Structures
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• 제31권4호
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• pp.373-380
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• 2020

For large-scale 5MW offshore wind turbines, the discrete equation of fluid domain and the motion equation of structural domain with geometric nonlinearity were built, the three-dimensional modeling of the blade considering fluid-structure interaction (FSI) was achieved by using Unigraphics (UG) and Geometry modules, and the numerical simulation and the analysis of the vibration characteristics for wind turbine structure under rotating effect were carried out based on ANSYS software. The results indicate that the rotating effect has an apparent effect on displacement and Von Mises stress, and the response and the distribution of displacement and Von Mises stress for the blade in direction of wingspan increase nonlinearly with the equal increase of rotational speeds. Compared with the single blade model, the blade vibration period of the whole machine model is much longer. The structural coupling effect reduces the response peak value of the blade displacement and Von Mises stress, and the increase of rotational speed enhances this coupling effect. The maximum displacement difference between two models decreases first and then increases along wingspan direction, the trend is more visible with the equal increase of rotational speed, and the boundary point with zero displacement difference moves towards the blade root. Furthermore, the Von Mises stress difference increases gradually with the increase of rotational speed and decreases nonlinearly from the blade middle to both sides. The results can provide technical reference for the safe operation and optimal design of offshore wind turbines.

• 한국지반공학회지:지반
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• 제1권1호
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• pp.73-84
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• 1985

본 연구에거는 유한요소법에 의해서 제상하중을 받고 있는 연약지반의 응력분포와 변위를 규명하 였다. 응력에는 체적응력, 간극수압, 연직응력, 수평응력, 전단응력이 포함된다. 유한요소기법으로서 Christian-Boehmer방법을 택하였으며 진배수 및 비배수조건에서 일반탄성model과 참정 Cam-clay model을 지배방정으로 선정하였다. 그 결과는 다음과 같다. 1. 체적응력은 간극수압과 거의 일치한다. 이는 비배수조건에서 전응력이 간극수탄과 같다는 것 을 의미한다. 2. 연직응력은 배수 및 비배수표건이라 구성식의 model에 관계없이 같은 갈을 나타런다. 3. 수평응력은 배수조건과는 무관하지만 구함식의 model에 따라서 다른 값으로 나타난다. 4. 전단응력은 배수조건 및 구성식의 model model에 따라 다른 값이 된다. 수정 Cam-clay에 의한 해석치가 가장 크게 된다. 5. 변위 Vector의 방향은 하중이 증가하는 동안 성토법면근방에서 외향으로 향한다. 6. 변위의 크기는 수정 Cam-clay에 의한 해석이 탄성 model의 2배가 된다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2007년도 춘계학술대회 논문집
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• pp.241-245
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• 2007

The residual stress in axial stress in the axial direction of the steel filaments has been measured by using a method based on the combination of the focused ion beam (FIB) and high resolution strain mapping program (VIC-2D). That is, the residual stress was calculated from the measured displacement field before and after the introduction of a slot along the steel filaments. The displacement was obtained by the digital correlation analysis of high-resolution scanning electron micrographs, while the slot was introduced by FIB milling with low energy beam. The present measurement revealed that the residual stress within 8% of the magnitude was persistent in the steel filaments fabricated.

• Transactions on Electrical and Electronic Materials
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• 제5권2호
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• pp.61-65
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• 2004

Bolt-tightened Langevin type vibrators using longitudinal mode of bar were designed and fabricated. In order to amplify the displacement of the tip of the vibrators, stacked ceramics were used and five different shapes of the horns were designed and jointed. Resonant frequencies and vibration characteristics of vibrators and horns were analyzed by ANSYS(finite element analysis computer program), and the displacements of tips of the horns were measured. As results, when the numbers of the stacked ceramics were increased, the displacements of the tips were increased and the driving voltages were decreased. Step l horn (BLT-St1) showed maximum displacement of 36.92 $\mu\textrm{m}$ at 36.7 ㎑ with 45 V$\sub$rms/ and 0.11 A. The displacement amplification ratio was about 5.2. But, the stress of step l horn was concentrated on intersection, where two diameters meet. To lessen the stress, step3 shaped hem is recommended.

• Structural Engineering and Mechanics
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• 제22권4호
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• pp.469-481
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• 2006

A new method called fuzzy factor method for the stationary stochastic response analysis of fuzzy truss with global fuzzy structural parameters is presented in this paper. Considering the fuzziness of the structural physical parameters and geometric dimensions simultaneously, the fuzzy correlation function matrix of structural displacement response in time domain is derived by using the fuzzy factor method and the optimization method, the fuzzy mean square values of the structural displacement and stress response in the frequency domain are then developed with the fuzzy factor method. The influences of the fuzziness of structural parameters on the fuzziness of mean square values of the displacement and stress response are inspected via an example and some important conclusions are obtained. Finally, the example is simulated by Monte-Carlo method and the results of the two methods are close, which verified the feasibility of the method given in this paper.

• 한국기계가공학회지
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• 제11권3호
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• pp.122-129
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• 2012

This study investigates structural and vibration analyses according to the thickness of bicycle frame tube. The model of bicycle frame has the dimension as length of 862mm, width of 100mm and hight of 402.5mm. There are 3 kinds of models with tubes of top, down and seat at bicycle frame as thicknesses of 10, 15 and 20mm. The maximum displacement and stress occur at the center part of seat stay and at the installation part of rear wheel respectively. Maximum displacements become 0.031936, 0.029159 and 0.027984mm in cases of thicknesses of 10, 15 and 20mm respectively. In case of thickness of 20mm among 3 cases, maximum displacement becomes lowest. But maximum stresses become 10.019, 8.5492 and 9.2511MPa in cases of thicknesses of 10, 15 and 20mm respectively. In case of thickness of 15mm among 3 cases, maximum stress becomes lowest. There is no resonance at practical driving conditions and natural frequency remains almost unchanged along the change of thickness. In case of the displacement due to vibration mode, the displacement difference at thickness between 15mm and 20mm becomes 1/2 times than that between 10mm and 15mm. Design at bicycle frame tube becomes most economical and durable effectively in case of thickness of 15mm among 3 cases.

• 한국재난정보학회 논문집
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• 제12권1호
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• pp.40-46
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• 2016

Nowdays, adjacent loading bringing enormous harm to the existing bridge in engineering construction. In this paper, the influencing mechanism of adjacent loading to pier and Law of displacement of pier is researched through living examples, and the safe influence area has been defined. Research shows that: the main damages to piers is caused by the side loading; lateral displacement index of pier top surface is more conservative than the pier additional stress index; it is secure when the distance of adjacent load is 0.5 times of the height of accumulation or 6m, otherwise it would be very scary, and the monitoring measure is necessary.