• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1998년도 봄 학술발표회 논문집
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• pp.33-40
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• 1998

Although a structural analysis based on e linear elastic theory yields good results for deformations and stresses produced by working loads, it fails to assess the teal load-carrying of the plates on the verge of yielding. In case of a limit analysis of plates, the yield line theory is widely used on the basis of the upper bound theorem and theoretically it overestimates the strength of the plate. There is, therefore, a general need for analytical methods of predicting the inelastic behavior and load-carrying capacities of plate subjected to arbitrary loadings and boundary conditions. The $\rho$-version of finite element method has been presented for determining the accurate limit load of plates. The numerical results by $\rho$-version model compares with the results obtained by the h-version software ADINA as well as with the available analytical solutions in literatures.

• Structural Engineering and Mechanics
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• 제10권2호
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• pp.181-195
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• 2000

A two-step procedure for the application of non linear constrained programming to the limit analysis of rigid brick-block systems with no-tension and frictional interface is implemented and applied to various masonry structures. In the first step, a linear problem of programming, obtained by applying the upper bound theorem of limit analysis to systems of blocks interacting through no-tension and dilatant interfaces, is solved. The solution of this linear program is then employed as initial guess for a non linear and non convex problem of programming, obtained applying both the 'mechanism' and the 'equilibrium' approaches to the same block system with no-tension and frictional interfaces. The optimiser used is based on the sequential quadratic programming. The gradients of the constraints required are provided directly in symbolic form. In this way the program easily converges to the optimal solution even for systems with many degrees of freedom. Various numerical analyses showed that the procedure allows a reliable investigation of the ultimate behaviour of jointed structures, such as stone masonry structures, under statical load conditions.

• 한국통계학회:학술대회논문집
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• 한국통계학회 2000년도 추계학술발표회 논문집
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• pp.109-113
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• 2000

We consider the probability that the total population of a Jackson network exceeds a given large value. By using the relation to the stationary distribution, we derive upper and lower bounds on this probability. These bounds imply the stronger logarithmic limit than that in Glasserman and Kou(1995) when several nodes have the same maximal load.

• 한국통계학회:학술대회논문집
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• 한국통계학회 2000년도 추계학술발표회 논문집
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• pp.115-118
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• 2000

In this paper we establish limit results on the increments of (N, d)-Gaussian processes with independent components, via estimating upper bounds of large deviation probabilities on the suprema of (N, d)-Gaussian processes.

• 대한수학회논문집
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• 제15권2호
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• pp.379-390
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• 2000

In this paper the limit theorems on lag increments of a Wiener process due to Chen, Kong and Lin [1] are developed to the case of a Gaussian process via estimating upper bounds of large deviation probabilities on suprema of the Gaussian process.

• 한국정밀공학회지
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• 제17권2호
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• pp.144-150
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• 2000

In this paper, the formation of a corner cavity in the final stage of axisymmetric backward extrusion process is studied by means of upper bound analysis using kinematically admissible velocity. The quantitative relationships between corner cavity formation and process parameters are studied. And analytical results are compared with those of experiment to which plasticine is used. It is found that the analytical results agree well with experimental one. In addition, to restrict the formation of a corner cavity, driven container is applied to backward extrusion and the results are compared with those of FEM. The critical thickness of the bottom of the billet decreases with increase in reduction of area, and increases with decrease in friction. To prevent the formation of corner cavity, the concept of moving container was applied. Throughout this process, the occurrence of a corner cavity is delayed and forming limit area is enlarged.

• Advances in materials Research
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• 제5권4호
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• pp.263-277
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• 2016

Mechanical properties of $Al/Al_2O_3$ and $Al/B_4C$ composites prepared through powder metallurgy are estimated up to 50% $Al_2O_3$ and 35% $B_4C$ weight fractions using micromechanics models and experiments. The experimental Young's modulus up to 0.40 weight fraction of ceramic is found to lie closely between Ravichandran's/Hashin-Shtrikman lower/upper bounds, and close to self consistent method/Miller and Lannutti method/modified rule of mixture/fuzzy logic method single value predictions. Measured Poisson's ratio lies between rule of mixture/Ravichandran lower and upper bound/modified Ravichandran upper bounds. Experimental Charpy energy lies between Hopkin-chamis method/equivalent charpy energy/Ravichandran lower limit up to 20%, and close to the reciprocal rule of mixture for higher $Al_2O_3$ content. Rockwell hardness (RB) and Micro-hardness of $Al/Al_2O_3$ are closer to modified rule of mixture predictions.

• 한국군사과학기술학회지
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• 제3권2호
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• pp.35-41
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• 2000

A modified theoretical analysis of the ballistic perforation on the double and multi-layered armour plates using an upper bound method has been presented in this paper. A modified model based on the suggestion of the Awerbuch-bodner model has been adapted and extended into double and multi-layered armour plates when the plugging type of penetration has been occurred. The residual projectile speed, ballistic limit velocity and contact time during the penetration process have been derived from the equation of motion at each stage.

• Geomechanics and Engineering
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• 제22권3호
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• pp.265-275
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• 2020

As a flexible supporting structure, the anchoring frame structure is widely adopted to support multistage slopes in high earthquake-intensity area for its effectiveness and practicality. The previous study indicates that the anchor of anchoring frame structure is the most likely to be damaged during earthquakes. It is crucial to determine the pull-out capacity of anchor against seismic force for the seismic design of anchoring frame structure. In this study, an analytical model of a three-stage slope supported by anchoring frame structure is established, and the upper bound method of limit analysis is applied to deduce the seismic anchor force of anchoring frame structure. The pull-out capacity of anchor against seismic force of anchoring frame structure at each stage is obtained by computer programming. The proposed method is proved to be reasonable and effective compared with the existing published solution. Besides, the influence of main parameters on the pull-out capacity of anchor against seismic force is analyzed to provide some recommendations for the seismic design of anchoring frame structure.

• 한국항만경제학회지
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• 제20권2호
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• pp.73-87
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• 2004

The purpose of this paper is to setup reasonable criterion for underwriters to reimburse the expenses of suing and labouring incurred by assured, using game theory. As for the upper limit for the reimbursement, MIA and ICC do not mention at all but stipulate that proper and reasonable expenses shall be reimbursed, while ITC-Hulls set the amount insured as the upper limit to compensate the sum of expenses and damage loss. And as for failed measures of averting and minimizing loss, MIA and ICC do not mention either, while ITC-Hulls stipulates underwriters shall compensate the expenses and damage loss within the amount insured. The main results of this paper are as follows: First, it is for the benefit of underwriters to reimburse the expenses incurred to take such reasonable measures to avert or minimizing a loss which would be recoverable under the insurance. Second, the expenses of single measure should not be above the amount insured. Third, even if the measures failed, the expense should be reimbursed if it is less than the expected value of the subject-matter insured that could be recovered by the measures. Last, if the measures are taken several times individually, even if the sum of expenses might be above the amount insured, it should be reimbursed.