• 한국가스학회지
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• 제14권5호
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• pp.19-25
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• 2010

본 연구에서는 o-xylene+n-pentanol 및 m-xylene+n-hexanol 계의 인화점을 Tag 개방식 장치(ASTM D1310-86)를 이용하여 측정하였다. 실험값은 Raoult의 법칙, van Laar 및 Wilson 식을 이용한 계산된 값들과 비교하였다. 그 결과, 최적화법에 의한 예측값이 Rauolt의 법칙에 의한 계산 보다 실험값에 더욱 근접하였다. 또한, van Laar 식을 사용한 최적화법이 Wilson 식에 의한 최적화법 보다 실험값에 대한 모사성이 우수하였다.

• 한국자동차공학회논문집
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• 제16권4호
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• pp.63-68
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• 2008

The fatigue characteristics of bevel gear used for differential gear of automobile was investigated in this paper. From the A-N(Almen intensity-Number of fracture)curve of bevel gear it was shown that there was a specific time that have a maximum fatigue life. Optimal peening condition was 65m/s of project velocity and 8min of project time. Fatigue life was also investigated from the S-N curve between optimal peened specimen and unpeened specimen. Another very significant point is that the crack initiation of bevel gear by shot peening was generated in the subsurface from fractography. This paper shows that shot peening process tremendously improve fatigue characteristics of bevel gear.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 추계학술대회 논문집
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• pp.39-40
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• 2006

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 추계학술대회 논문집
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• pp.243-244
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• 2006

• Advanced Composite Materials
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• 제16권1호
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• pp.31-44
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• 2007

The purpose of this study is to improve the examining and understanding of the bonding behavior of Fiber Reinforced Polymer (FRP) sheets bonded to concrete blocks and steel plates under fatigue loading. First, a series of experimental investigations is summarized in the paper. The fatigue behavior of bonding surface between FRP sheets and concrete is finally characterized by the conducted P-S-N diagram representing the relationship among the probability of FRP debonding (P), the bond stress amplitudes (S), and the number of cycles (N) at debonding on a semi-logarithmic scale. The different debonding modes for various fracturing surface are also investigated and evaluated.

• 한국농공학회지
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• 제41권4호
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• pp.92-103
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• 1999

Recently structural damage has been frequently observed in reinforced concrete brdiges due to repeated loads such as vehicular traffic an due to continual overloads by heavy duty trucks. Therefore, the purpose of this experimental stduy is to investigate the damage mechanism due to fatigue behavior of high-strength reinforced concrete beams under repeated loads. From the test results, the relation of cycle loading to deflection is on the mid-span , the crack growth and the modes of failure according to cycle number, fatigue life and S-N curve were observed through the fatigue test. Based on the fatigue test results , high-strength reinforced concrete beams failed to 57 ∼66 percent of the static ultimate strength . Fatigue strength aobut two million cycles from S-N curves was certified by 60 percent of static ultimate strength.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2004년도 학술대회지
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• pp.291-296
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• 2004

The paper describes a test program on welded K-joints fabricated from circular hollow section brace members and chords made with API 2W 50 grade steel produced by POSCO. The K-joints were tested for three loading conditions at RIST. The specimens were tested in reaction frame that allowed vertical uniform loading to the structure. From the test, the crack initiation and development were observed and the fatigue failure could be predicted. The results were also compared with the provided S-N curves by DnV.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.359-364
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• 2004

We investigated the effect of weld details on fatigue behavior of a material, JIS SM 490 A, with yielding strength of about 350 MPa and tensile strength of about 520 MPa. Tensile tests, instrumented indentation tests and fatigue tests were carried out on double V-grooved butt weld plates such as reinforcement removed, as-welded and weld toe ground. In addition plates with transverse fillet welded web, load carrying cruciform fillet welded plates, non-load-carrying cruciform fillet welded plates and longitudinal butt welded plates were tested. S-N curves for the above specimens were obtained and analyzed

• Journal of Electrical Engineering and Technology
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• 제11권4호
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• pp.939-942
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• 2016

One of the most important characteristic curves of a solar cell is its current density-voltage (J-V) curve under AM1.5G insolation. Solar cell can be considered as a semiconductor diode, so a diode equivalent model was used to estimate its parameters from the J-V curve by numerical simulation. Active layer plays an important role in operation of a solar cell. We investigated the effect thicknesses and defect densities (N_d) of the active layer on the J-V curve. When the active layer thickness was varied (for N_d = 8×10¹⁷ cm^-3) from 800 nm to 100 nm, the reverse saturation current density (J_o) changed from 3.56×10^-5 A/cm² to 9.62×10^-11 A/cm² and its ideality factor (n) changed from 5.28 to 2.02. For a reduced defect density (N_d = 4×10¹⁵ cm^-3), the n remained within 1.45≤n≤1.92 for the same thickness range. A small increase in shunt resistance and almost no change in series resistance were observed in these cells. The low reverse saturation current density (J_o = 9.62×10^-11 A/cm²) and diode ideality factor (n = 2.02 or 1.45) were observed for amorphous silicon based solar cell with 100 nm thick active layer.

• 대한기계학회논문집
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• 제7권4호
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• pp.425-433
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• 1983

Fatigue tests by axial loading (R=0.1) were carried out to investigate fatigue crack growth properties of small surface cracks in mild steel at room temperature, 250.deg. C and 400.deg. C, by using flat specimens with a small artificial pit. All the data of the fatigue crack growth rate obtained in the present tests are determined as a function of the stress intensity factor range, so that the applicability of liner fracture mechanics to the fatigue crack growth of surface cracks at elevated temperatures is investigated and discussed in comparison with the data of type 304 stainless steel at room temperature and elevated temperature. The obtained results are as follows: 1) Relations of both surface fatigue crack length and its depth to cycle ratio fall within a narrow scatter band in spite of different stress levels. 2) The .DELTA. .sigma. .root. .pi. a-da/dN relation of surface fatigue crack growth at room temperature is independent of the stress level and can be plotted as a straight line at log-log diagram, but the relation at 400.deg. C depends partly on the stress level. 3) Relations of the fatigue crack growth into depth d(2b)/dN and is stress intensity factor range .DELTA. $K_{I}$, accounted for the aspect ratio variation, fall within a narrow scatter band for wide range of the applied stress levels. And .DELTA. $K_{I}$E-d(2b)/dN relations of mild steel at different stress level coincide relatively well with the data of type 304 stainless steel. 4) The value of aspect ratio obtained by a beach mark method and a temper coloring method approaches about 0.9 in common with crack growth and it is independent of stress level and temperatures. 5) The equi-crack length curve is parallel to S-N$_{f}$ curve at elevated temperatures.s.s.s.