• Journal of the Computational Structural Engineering Institute of Korea
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• v.29 no.6
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• pp.491-498
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• 2016

Stress on plates may increase in the neighborhood the edges or the holes for rivets or bolts. Excessive stress concentration may lead to severe breakage of the plates. Thus, it is important to conduct optimization of arrangement of holes at the design stage. In this paper, accuracy of FEM analysis was examined for such stress concentration. By changing the hole size on a narrow plate, change of the stress concentration factor(K) was investigated. Additionally, the same experiment was conducted about series of multiple holes on plate to investigate interaction between the adjacent holes. Then, the FEM results were compared to the reference predictions respectively. Finally, a method by which simple stress concentrating situations can be optimized, will be suggested. This method was examined by FEM, and showed similar tendency with the expectation. Therefore, this method can be valuable when arranging the holes on a plate.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.5 no.2
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• pp.207-214
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• 2015

Stress concentrations around discontinuities, such as a hole or a sudden change in cross section of a structural member, have great important cause in the most materials failure because the stress near the points of application of concentrated loads can reach values much larger than the average value of the stress in the member. This paper presents the stress concentrations between fillet and hole at different locations in a stepped plate under tensile loading. The analysis for interaction effect of stress concentration was performed by photoelasticity and ANSYS which is a commercial finite element software. From the analysis results, the circular hole located at the different position from the fillet radius can cause different values of stress concentration factor within interacting region.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.5
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• pp.513-523
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• 2016

The stress concentration factors and stress intensity factors for a simple beam and a cantilever are analyzed by using finite element method and phtoelasticity. Using the analyzed results, the estimated graphs on stress concentration factors and stress intensity factors are obtained. To analyze stress concentration factors of notch, the dimensionless notch length H(height of specimen)/h=1.1~2 and dimensionless gap space r(radius at the notch tip)/h=0.1~0.5 are used. where h=H-c and c is the notch length. As the notch gap length increases and the gap decreases, the stress concentration factors increase. Stress concentration factors of a simple beam are greater than those of a cantilever beam. However, actually, the maximum stress values under a load, a notch length and a gap occur more greatly in the cantilever beam than in the simple beam. To analyze stress intensity factors, the normalized crack length a(crack length)/H=0.2~0.5 is used. As the length of the crack increases, the normalized stress intensity factors increase. The stress intensity factors under a constant load and a crack length occur more greatly in the cantilever beam than in the simple beam.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.5
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• pp.1069-1078
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• 1990

It is shown that the performance of finite element based on energy orthogonal functions may be superior to conventional formulation for plane stress problem. Using this finite element, it is then attempted to show the distribution of stress concentration effect for subsurface under loading point. It turned out that the stress concentration effect for subsurface is not dependent on the width of the member but the loading area. And then it is shown that the solution attained by taking the stress function as a Fourier series is not satisfactory in y<0.1B.

• Transactions of the Korean Society of Mechanical Engineers
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• v.8 no.2
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• pp.127-132
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• 1984

In this paper, stress concentration factor and distribution of slotted or notched plate which is subjected to uniaxial tensile load are studied. The experimental measurements have shown the following; (1)The stress around slot or notch of slotted or notched plate which is subjected to uniaxial tensile load is state of biaxial stress, which is mainly varied to notch radius and depth. (2)The stress concentration factor around slot or notch is mainly influenced by the .sigma.$_{yy}$ , it is varied with notch radius and depth. (3)For the notched specimen, there is a notch depth where stress concentration factor is maximum. On the other hand, for the slotted specimen, stress concentration factor increases as the notch depth increases. An investigation of the relationship between fracture and stress concentration factor due to the slot or notch will be presented on the later paper, for reference.

• Journal of the Society of Naval Architects of Korea
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• v.33 no.3
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• pp.1-7
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• 1996

The stress concentration factor gives the significant effect the fatigue strength of welded joints. The model used herein is the type of the load carrying fillet welded cruciform joint with full or partial penetration. In order to obtain the stress concentration factor at the weld toe of fillet joint, the reasonable element size of the toe part is investigated and the stress analysis for the series models by FEM under tensile load is performed. On the basis of the calculation results, the estimated formulae for the stress concentration factor(Kt) at weld toe part of the fillet welded joint, which the effect of toe radius, flank angle and other parameters are taken into account, is derived.

• Journal of the Society of Naval Architects of Korea
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• v.35 no.4
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• pp.46-54
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• 1998

In this paper, the erect of notch geometries on dynamic stress concentration was investigated by using the dynamic photoelasticity and the drop weight loading system Dynamic stress fields arisen by elastic wave through the loading system around various types of notch geometries were captured by using $10^6/sec$ frame rate Cranz-Shardin camera system with 12 photographic frames. We found that dynamic stress concentrations around the notch tip and comer were highly dependent on the change in notch geometries. The elders of dynamic stress singularity ware determined with respect to varying geometries of notches and we explained dynamic stress concentration in terms of the orders of dynamic stress singularity.

• Journal of Dental Rehabilitation and Applied Science
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• v.26 no.1
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• pp.39-46
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• 2010

To assess the stress distribution of implant prosthesis induced by intentional misfit using photoelastic model. Stress was measured at the surrounding bone after applying vertical load to the implant. Three implants were placed in each of three photoelastic resin blocks. No misfits were used for the control group, while for the experimental group $100{\mu}m$ misfit after cutting the crown was used. The photoelastic stress analysis was performed. In control group, stress concentration was not shown when the load was not applied, whereas stress concentration was shown only in the loaded part even when load was applied and the stress was distributed in anterior-posterior direction when applying a load in the middle. When intentional misfits were given, stress around the fixture was incurred when tightening the screw even if load was not applied. If the load was applied, stress was concentrated around the implants including areas where the load was applied. In particular, the prosthesis made of UCLA showed more stress concentration as compared with a conical abutment. In the UCLA case, concentration was shown from the apex following through the axis to the cervical area. Prosthesis with misfit makes the stress concentrated though the load was not applied and it induces even more severe stress concentration when the load was applied. This founding demonstrates the importance of the correct prosthesis production.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.3
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• pp.333-340
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• 2011

We evaluated the stress-reduction effect for different shapes of a composite adherend with or without a spew fillet. Six different single-lap joint specimens were modeled and assessed using nonlinear finite element analysis. Moreover, we investigated the effect of the stiffness ratio of the adherend and adhesive. The single-lap joint with normal tapering had the highest stress values, and the single-lap joint with reverse tapering and a spew fillet had the lowest stress values. The composite adherends with higher stiffness had lower stress values, and the adhesives with lower stiffness had lower stress values.

• Journal of Welding and Joining
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• v.10 no.1
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• pp.35-42
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• 1992

In this study, the stress concentration phenomenon for the dissimilar joints(ceramic-metal) bonded by thermal treating using a soft-insert metal(copper) was investigated with the aid of FEM(finite element method) under the load condition of uniform tension. The analysis was carried out by the supposing that stress states are plane stress or plane strain and elastic or elastic-plastic. And the Von Mises yield criterion and the incremental theory as plastic flow were adopted in this analysis. As the summarized results obtained, the stress concentration phenomenon was severer as the soft insert metal was thicker, in plane strain than in plane stress and in elastic-plastic state than in elastic state. Furthermore, the inducing mechanism of stress concentration was well expressed by the constraint forces(Fc) generated between the soft and the hard material.