• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.10
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• pp.1299-1306
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• 2011

In this study, crack-growth model parameters subjected to variable amplitude loading are estimated in the form of a probability distribution using the method of Bayesian parameter estimation. Huang's model is employed to describe the retardation and acceleration of the crack growth during the loadings. The Markov Chain Monte Carlo (MCMC) method is used to obtain samples of the parameters following the probability distribution. As the conventional MCMC method often fails to converge to the equilibrium distribution because of the increased complexity of the model under variable amplitude loading, an improved MCMC method is introduced to overcome this shortcoming, in which a marginal (PDF) is employed as a proposal density function. The model parameters are estimated on the basis of the data from several test specimens subjected to constant amplitude loading. The prediction is then made under variable amplitude loading for the same specimen, and validated by the ground-truth data using the estimated parameters.

• Bulletin of the Society of Naval Architects of Korea
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• v.20 no.4
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• pp.17-24
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• 1983

In this study, it was investigated the distribution of residual stress in the direction of loading between the root and toe the load fillet welds for thick steel plate. Residual stress distributions are measured by sectioning method which is one of stress-relaxation technique in welded joint, and analyzed by two dimensional finite element method on thermo-elasto-plastic theory under plane stress condition. These are compared the results of F.E.M analysis with the experimental result by stress-relaxation techniques. As a results, the following conclusion were obtained. (1) In the no penetration fillet welded joint specimen using mild steel plate with 25mm in thickness, the residual stress of loading direction near the root was about $10kg/mm^2$ tensile. (2) The tensile residual stress has been observed in fillet region of the fillet joint by F.E.M. analysis method. (3) The range of compressive residual stress distribution from the root was largest in the case of 5mm root penetration.

• Journal of Technologic Dentistry
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• v.31 no.1
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• pp.7-15
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• 2009

Purpose: This study was to propose the clear understanding for stress distribution of supporting bone by use of staggered buccal offset tripodal placement of fixtures of posterior 3 crown implant partial dentures. We realized posterior 3 crown implant fixed partial dentures through finite element modeling and analysed stress effect of implant arrangement location to supporting bone under external load using finite element method. Method: To understand stress distribution of 3 crown implant fixed partial dentures which have 2 different arrangement by finite element analysis. In each model, for loading condition, we applied $45^{\circ}$ oblique load to occlusal surface of crown and applied 100 N for 3 crown individually(total 300 N) for imitating possible oral loading condition. at this time, we calculated Von Mises stress distribution in supporting bone through finite element method. Result: When apply $45^{\circ}$ oblique load to in-line arrangement model, maximum stress result for 100 N for each 3 crown 47.566MPa. In tripodal placement, result for 1mm buccal offset tripodal placement implant model was maximum distributed load 51.418MPa, so result was higher than in-line arrangement model. Conclusion: In stress distribution result by placement of implant fixture, the most effective structure was in-line arrangement. The tripodal placement does not effective for stress distribution, gap cause more damage to supporting bone.

• Wind and Structures
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• v.20 no.4
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• pp.489-508
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• 2015

In this paper, a novel methodology is proposed to obtain optimum location of outriggers. The method utilizes genetic algorithm (GA) for shape and size optimization of outrigger-braced tall structures. In spite of previous studies (simplified methods), current study is based on exact modeling of the structure in a computer program developed on Matlab in conjunction with OpenSees. In addition to that, exact wind loading distribution is calculated in accordance with ASCE 7-10. This is novel since in previous studies wind loading distributions were assumed to be uniform or triangular. Also, a new penalty coefficient is proposed which is suitable for optimization of tall buildings. Newly proposed penalty coefficient improves the performance of GA and results in a faster convergence. Optimum location and number of outriggers is investigated. Also, contribution of factors like central core and outrigger rigidity is assessed by analyzing several design examples. According to the results of analysis, exact wind load distribution and modeling of all structural elements, yields optimum designs which are in contrast of simplified methods results. For taller frames significant increase of wind pressure changes the optimum location of outriggers obtained by simplified methods. Ratio of optimum location to the height of the structure for minimizing weight and satisfying serviceability constraints is not a fixed value. Ratio highly depends on height of the structure, core and outriggers stiffness and lateral wind loading distribution.

• Journal of Advanced Marine Engineering and Technology
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• v.30 no.3
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• pp.420-427
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• 2006

This paper describes design and characteristic analysis of the 200[kW], 3000[rpm] induction motor for gearless turbo machine. It was designed by the loading distribution method and the results of characteristics obtained by the equivalent circuit method are compared with the results of circle diagram. To verify the validation of design 2D finite element method is used and also 3D finite element method is used to calculate the current density curve of the rotor bars when they are broken.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.2237_2238
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• 2009

This paper describes the design process of three-phase squirrel cage induction moter. stator and rotor were modelled with the result obtained from loading distribution on the provided specification. For proving validity of the result obtained from loading distribution, through Maxwell simulator the first test target values, output and efficency, synchronous speed and etc, were compared with the design result.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.2239_2240
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• 2009

This paper describes the design process of three-phase Synchronous generator. stator and rotor were modelled with the result obtained from loading distribution on the provided specification. For proving validity of the result obtained from loading distribution, through Maxwell simulator the first test target values, output and efficiency, Rated speed and etc, were compared with the design result.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.11
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• pp.58-66
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• 2011

In this paper, the starting torque and efficiency characteristics of the induction motor (IM) for the electric vehicle (EV) are improved by changing the slot shapes of squirrel cage. The initial model of the induction motor is designed by the loading distribution method (LDM), and then the rotor with squirrel cage of NEMA class A is selected to optimize the slot shape by response surface method(RSM). The design variables of rotor slot shape are obtained by the RSM. Starting torque and efficiency were calculated by the equivalent circuit method. As a result, starting torque and efficiency of the optimized model shows good performance through whole-speed range.

• Bulletin of the Society of Naval Architects of Korea
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• v.7 no.2
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• pp.27-40
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• 1970

The distribution of stress and strain in elastic stages is investigated by the experiments of two dimensional photoelastic coating and Moire fringe method. Center block type and cover plate type of fillet welds are used as specimens in the test. The results are as follows. 1) Center block type gets less uniform stress distribution than cover plate type. And its stress concentration factor, especially at root, is larger than that at toe. 2) When main plate and cover plate closely contact and it cause friction, stress concentration decreases more than that in case of slit. That is because stress can be transmitted on the contact surface. 3) When slit is made, the outside of fillet gets more stress than the inside of it. 4) While the plastic strain distribution of center block type reaches the maximum at root and differs very slightly from that under lower loading, the plastic strain distribution of cover plate type is inclined to get the maximum at the outside of fillet rather than at root. 5) When the plastic strain value of cover plate type is compared with that of center block type at toe and root, the relations between the former and the latter shows root<toe and root>toe. 6) Because stress distribution becomes changed according to loading, fracture angle cannot be estimated by the peaks of elastic stress distribution. 7) The strain distribution just before fracture can be found by Moire fringe method.

• The Journal of Korean Academy of Prosthodontics
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• v.44 no.1
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• pp.85-102
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• 2006

Statement of problem: Currently, there are some 20 different geometric variations in implant/abutment interface available. The geometry is important because it is one of the primary determinants of joint strength, joint stability, locational and rotational stability. Purpose: As the effects of the various implant-abutment connections and the prosthesis height variation on stress distribution are not yet examined this study is to focus on the different types of implant-abutment connection and the prosthesis height using three dimensional finite element analysis. Material and method. The models were constructed with ITI, 3i TG, Bicon, Frialit-2 fixtures and solid abutment, TG post, Bicon post, EstheticBase abutment respectively. And the super structures were constructed as mandibular second premolar shapes with 8.5 mm, 11 mm, 13.5 mm of crown height. In each model, 244 N of vertical load and 244 N of $30^{\circ}$ oblique load were placed on the central pit of an occlusal surface. von Mises stresses were recorded and compared in the crowns, abutments, fixtures. Results: 1. Under the oblique loading, von Mises stresses were larger in the crown, abutment, fixture compared to the vertical loading condition. 2. The stresses were increased proportionally to the crown height under oblique loading but showed little differences with three different crown heights under vertical loading. 3. In the crown, the highest stress areas were loading points under vertical loading, and the finish lines under oblique loading. 4. Under the oblique loading, the higher stresses were located in the fixture/abutment interface of the Bicon and Frialit-2 systems compared to the ITI and TG systems. Conclusions: The stress distribution patterns of each implant-abutment system had difference among them and adequate crown height/implant ratio was important to reduce the stresses around the implants.