• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 봄 학술발표회 논문집
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• pp.915-920
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• 2001

This study was conducted to analysis the distribution of the rectangular stress block for high-strength polymer concrete beam. C-shaped specimens were produced and tested to compute parameters of the rectangular stress block. They were $\kappa_{1}$ = 0.73, $\kappa_{3}$ = 0.94 and $\gamma$= 0.845, respectively. Experimental value of flexural strength of beam was same to be compared with theoretical value. But there is desirable to need many experimental data in order to exact design of polymer concrete structure.

• Communications for Statistical Applications and Methods
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• 제3권3호
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• pp.187-194
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• 1996

We treat the problem of estimating reliability R = P[Y < X] in the stress-strength model in which a unit of strength X is subfected to enviromental stress Y./ In this paper several nonparametric approaches to estimation of R are analyzed and compared by simulations.

• Journal of the Korean Statistical Society
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• 제27권4호
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• pp.435-449
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• 1998

In this paper, we consider the problem of constructing the lower cofidence intervals for the reliability P(X < Y z,w), where the stress X and the strength Y are the random variables with explanatory variables z and w, respectively. As an estimator of the reliability, a Mann-Whitney type statistic is considered. It is shown that under regularity conditions, the proposed estimator is asymptotically normal. Based on the result, the distribution free lower confidence intervals are constructed.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2008년도 추계 학술발표회 제20권2호
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• pp.843-846
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• 2008

Rationality of strength models for structural concrete depends on how to treat loads on boundaries and load paths within members. Differentiation between strut-and-tie models and stress fields approaches for shear strength models is discussed in this paper for salient use of current design formula in design code provisions. How to model configuration of loads and stress states along the boundary for the regions under provides a key to realistic construction of stress fields together with STM.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 1999년도 춘계 학술발표회 논문집 Proceedings of EESK Conference-Spring
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• pp.77-84
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• 1999

An assessment of liquefaction potential is made in principle by comparing earthquake induced shear stress to the liquefaction strength of the soil. In this research a modified method based on Seed and Idriss theory is developed for evaluating liquefaction strength of Jumunjon sand(Korean standard sand). Also the factors affecting liquefaction strenght such as cyclic shear stress amplitude and relative density are investigated and verified by using cyclic triaxial test. From the result the new relationships between cyclic shear stress ratio and number of load cycles are proposed for evaluating liquefaction strength under moderated magnitude(M=6.5) of earthquake.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2012년도 추계 학술논문 발표대회
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• pp.263-264
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• 2012

In this study, the ultra high strength concrete which have 100, 150, 200MPa took the heat from 20℃ to 70 0℃ and the 0, 20% stress in normal condition's to evaluate stress-strain, residual compressive strength and thermal expansion deformation were evaluated. The heating speed of specimen was 0.77℃/min 20~50℃, 50℃ before the target temperature, and the other interval's heating speed was 1℃/min. As a result, the stress-strain curve of non-load specimen showed the liner behavior at high temperature when the specimen's strength increased more. If ultra high strength concrete got loads, its compressive strength tended to decrease different from the normal strength concrete. The thermal expansion deformation was expanded from a vitrification of quartz over 500℃. however, over the 600℃, it was shrinked because of the dehydration of the combined water.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집A
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• pp.137-142
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• 2001

In structural applications, brittle materials such as soda-lime glasses and ceramics are often subjected to multiaxial stress. Brittle materials with crack or damaged by foreign object impacts are abruptly fractured from cracks, because of their properities of very high strength and low fracture toughness. But in most cases, the residual strength has been derived from tests under uniaxial stress such as a 4-point bend test. The strengths under multiaxial stresses might be different from the strength. In comparable tests, the residual strength under biaxial stress state by the ball-on-ring test was greater than that under the uniaxial one by the 4-point bend test. In the case that crack having 90deg. to loading direction, the ratio of biaxial to uniaxial flexure strength was 1.12. At a different crack angle to loading direction when it was evaluated by the 4-point bend test, the residual strength was different and the ratio of 45deg. to 90deg. was 1.16.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1997년도 추계학술대회 논문집
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• pp.322-327
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• 1997

This paper investigates the effects of shot peening on mechanical properties of SAE 9254, which is a spring steel used for the suspension system of automobiles. Rotary Bending Fatigue test is accomplished and the results are summarized as fellows : 1. The tensile strength and the hardness do not change so much. 2. The layer of highly residual stress is obtained by multi-stage shot peening. 3. The fatigue strength seems to be improved by residual stress. 4. The fatigue strength of un-peened and multistage shot peened material are 425 MPa and 756 MPa, respectively.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 추계 학술발표회 제16권2호
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• pp.675-678
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• 2004

The importance of predicting concrete compressive strength of in concrete structures is gradually increasing in construction industry. The estimation of concrete compressive strength of is a critical factor of the construction schedule and quality control. This study was performed to examine the relationship between concrete compressive strength and stress wave velocity which was determined by the impact echo method and SASW method.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1999년도 봄 학술발표회 논문집
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• pp.431-438
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• 1999

An assessment of liquefaction potential is made in principle by comparing the shear stress induced by earthquake to the liquefaction strength of the soil. In this study, a modified method based on Seed and Idriss theory is developed for evaluating liquefaction potential. The shear stress in the ground can be evaluated with seismic response analysis and the liquefaction strength of the soil can be investigated by using cyclic triaxial tests. The cyclic triaxial tests are conducted in two different conditions in order to investigate the factors affecting liquefaction strength such as cyclic shear stress amplitude and relative density. And performance of the modified method in practical examples is demonstrated by applying it to liquefaction analysis of artificial zones with dimensions and material properties similar to those in a typical field. From the result, the modified method for assessing liquefaction potential can successfully evaluate the safety factor under moderate magnitude(M=6.5) of earthquake.