• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.7 no.2
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• pp.437-444
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• 2017

Stress concentrations around discontinuities, such as a hole in cross section of a structural member, have great importance because the most materials failure around the region may be occurred. Stress on the point applied by concentrated load reaches much larger value than the average stress in structural member. In this paper, stress analysis was performed for the plate with a partial through-hole to find the difference of the principal stress distribution. The difference between maximum principal stress and minimum principal stress in photoelasticity is equal to the value obtained by multiplying the isochromatic fringe order by the fringe constant of the material divided by the distance through which the light passes, that is, the thickness of the specimen. Since the difference of principal stress is proportional to the photoelastic fringe order, the distribution of the principal stress difference by the finite element analysis can be compared with the photoelasticity experimental result. ANSYS Workbench, that is the finite element software, is used to compute the differences of principal stresses at the specific points on the measured lines. The computation values obtained by ANSYS are compared with the experimental measurements by photoelasticity, and two results are comparable to each other. In addition, the stress concentration factor is obtained using the stress distribution analyzed from the variation of hole depth. Stress concentration factor is increasing, as the depth of hole increase.

• Journal of Korean Tunnelling and Underground Space Association
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• v.7 no.2
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• pp.133-141
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• 2005

The behavior of the ground in crossed zone due to the excavation of new lower tunnel rectangularly crossed to that was studied by model tests and numerical analysis in shallow cover. Results of the model tests show that earth pressure of the ground in crossed zone were redistributed due to the longitudinal arching effect by the excavation of lower tunnel. By the numerical analysis, minimum principal stress in crown of single tunnel has more decrease than parallel tunnel or crossed tunnel. Vertical stress at rectangularly crossed tunnel decrease more than single tunnel by stress shadow.

• Journal of the Korean Society for Nondestructive Testing
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• v.24 no.1
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• pp.38-44
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• 2004

An experimental study for a crane hook was performed to investigate the stress distribution along a certain line where the maximum and minimum stresses to be developed. On this line, the isoclinic fringe and/or principal stress direction is constant. The crane hook was modeled into a 2-dimensional plate made of urethane rubber called 'Photoflex' The Photoflex is very sensitive to a load and has low photoelastic fringe constant. The Tardy compensation method with the fringe sharpening process and the 4-step phase shifting method, was used for the photoelastic technique. Experimental results by photoelasticity were compared with the calculated stresses from the simple curved beam theory and tile finite element analysis. Ail the results were close to each other.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.4A
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• pp.267-279
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• 2009

A numerical model that can simulate the nonlinear behavior of ultra high strength fiber reinforced concrete (UHSFRC) structures subjected to monotonic loading is introduced. The material properties of UHSFRC, such as compressive and tensile strength or elastic modulus, are different from normal strength reinforced concrete. The uniaxial compressive stress-strain relationship of UHSFRC is designed on the basis of experimental result, and the equivalent uniaxial stress-strain relationship is introduced for proper estimation of UHSFRC structures. The steel is uniformly distributed over the concrete matrix with particular orientation angle. In advance, this paper introduces a numerical model that can simulate the tension-stiffening behavior of tension part of the axial member on the basis of the bond-slip relationship. The reaction of steel fiber is considered for the numerical model after cracks of the concrete matrix with steel fibers are formed. Finally, the introduced numerical model is validated by comparison with test results for idealized UHSFRC beams.

• Journal of the Korean Geotechnical Society
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• v.20 no.9
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• pp.177-189
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• 2004

The backfilled space carl have various shapes such as vertical or lateral symmetric, unsymmetric slope depending on field conditions. Kellogg (1993) suggested the different equations for the backfill earth pressure and the lateral stress ratio considering that the stresses are different between the symmetrically sloped backfilled space and the vertical one. Kellogg (1993) assumed the stress generated on sloped wall surface as the simple internal friction angle of backfilled soil. However, Moon (1997) suggested modified Kellogg equation assuming that stress behavior in the sloped wall will be varied according to the rotation angle of principal stress and the friction of sloped wall surface. This study has compared and investigated the horizontal stresss of unsymmetrical backfilled space numerically and experimentally obtained when Kellogg lateral stress ratio is appled to and when average lateral stress ratio considering unsymmetric backfill slop of left and right are applied to the modified Kellogg equation. It is shown that the horizontal stress on the sloped wall has good match numerically and experimentally in the modified Kellogg equation when Kellogg's lateral stress ratio in symmetric condition is applied to the unsymmetric condition. But the horizontal stress on the vertical wall shows disagreement numerically and experimentally. The horizontal stress results in good agreement numerically and experimentally when the average lateral stress ratio of left and right at unsymmetric slop as applied to the modified Kellogg equation. Therefore, it is estimated that the application of the average lateral stress ratio to the left and right wall should be considered when backfilled space formed unsymmetric conditions.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.4
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• pp.310-320
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• 2009

In this paper, we estimate area-averaged solution of peening residual stress using a 3-D multi-impact symmetry-cell FE model. The symmetry-cell model includes factors reflecting peening phenomena and plastic shot. Area-averaged solution is much closer to XRD experimental solution than 4-node-averaged solution in plastic shot FE model. We then obtain FE Almen saturation curve corresponding to experimental Almen curve based on area-averaged solution. Using the curve, we obtain FE area-averaged solution in major peening materials, and compare the FE solution with experimental solution. In peening materials, surface, maximum compressive residual stress and deformation depth reach experimental solutions. Thus, FE Almen curve is useful for estimation of residual stress solution and could improve the efficiency of peening process. Consequently, it is confirmed that concept of area-averaged solution is the realistic analytical method for evaluation of peening residual stress.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1994.10a
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• pp.111-115
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• 1994

본 연구에서는 보강 되지 않은 사각단면 박스 구조물, 보강된 사각 단면 박스 구조물, 그리고 보강된 요철형 단면 박스 구좀ㄹ에 대하여 양단 고정(clamped-clamped)과 일단 고정 타단 자유(clamped-free)의 경계 조건에 대해 실험적 진동 해석을 수행 하였으며, 유한요소 code인 ANSYS를 이용하여 유한 요소 해석을 수행하였다. 또한 유한 요소 해석과 실험을 통하여 신뢰성이 검증된 요소를 각 박스 구조물에 적용하여 각 경우에 대한 응력해석을 유한요소법을 이용하여 수행하였다. 또한 각각의 경우에 보강재의 개수 및 단면 형상 변화, 그리고 두께 변화가 진동과 응력에 미치는 민감도를 연구하였다.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.73-78
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• 2004

In this research, the photoelastic experimental hybrid method with Hook-Jeeves numerical method has been developed: This method is more precise and stable than the photoelastic experimental hybrid method with Newton-Rapson numerical method with Gaussian elimination method. Using the photoelastic experimental hybrid method with Hook-Jeeves numerical method, we can separate stress components from isochromatics only and stress intensity factors and stress concentration factors can be determined. The photoelastic experimental hybrid method with Hook-Jeeves had better be used in the full field experiment than the photoelastic experimental hybrid method with Newton-Rapson with Gaussian elimination method.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.150-154
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• 2008

In this research, stress components and principal stresses of O-ring under internal pressure and under uniform squeeze rate were obtained from the stress freezing method of photoelastic experiment and photoelastic experimental Hybrid method for 3-dimensional problems. The obtaining processes of those were introduced. It was certified that the processes of those are effective for the 3-dimensional stress analysis of structures. Stress freezing method, the obtaining processes of those and photoelastic experimental hybrid method were effectively applied to the stress analysis of O-ring made from rubber that under uniform deformation and internal pressure. Stress components and principal stress of Oring under uniform squeeze rate and under internal pressure were analyzed.

• Journal of Korean Society of Steel Construction
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• v.10 no.3 s.36
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• pp.327-338
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• 1998

This paper presents the elastic behavior for panel zone and flange of connection in steel frame pier. The results of stress distributions on a series of experiments and FEM analysis models are reported herein. The investigations show that the shear stresses in the panel zone are varied with sectional-area ratio$(A_f/A_w)$ and also indicate that the nomal stresses in the flange due to the shea lag are significantly higher than the current design procedure. Based on the results, some new proposals considering the design parameters affecting connecting behavior are presented for the evaluations of stresses of panel zone and flange in connection.