• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.11
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• pp.1829-1834
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• 2001

The aim of this study is to investigate the ductile fracture behavior under mixed mode (I/II) loading using SA533B pressure vessel steel. Anti-symmetric 4-point (AS4P) bonding tests were performed to obtain the J-R curves under two different mixed mode (I/II) loadings. In addition, the fractographic examination of fracture surfaces was carried out to compare with those of pure Mode I and Mode II. In conclusions, the J-R curves under Mixed Mode (I/II) loading were located between those of Mode I and Mode II loadings. When the mixture ratio of mixed mode (I/II) loading was high, the J-R currie of mixed mode (I/II) loading approached that of pure mode I loading after some amount of crack propagation. In contrast with the above fact, if the mixture ratio was low, the J-R curve looked after that of pure mode II loading. The fractographic evidences such as the shape of dimples under different loading conditions supported these conclusions.

• Proceedings of the Korean Nuclear Society Conference
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• 1999.10a
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• pp.271.2-271
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• 1999

• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.4
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• pp.761-769
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• 1994

Actual load acting on rail surface in the track is the combined mode loading due to the contact rolling load of the wheels. To investigate the fracture behavior on rail steel under combined modes I and II, fracture tests were performed by using the test jigs and fracture specimen which were designed by Richard. The analysis results of experimental fracture data were compared with various fracture criteria that have been introduced for determination of the crack propagation direction and the critical stress of fracture of a crack submitted to a mixed mode loading. From the results, it was shown that the actual crack propagation direction of rail steel agree with the crack propagation directions predicted by maximum tangential stress criterion and strain energy density criterion, and that fracture criterion follows principal strain criterion.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.725-728
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• 2004

In this study, the effect of mode II by variation of multilevel loading direction was experimentally investigated in the fatigue crack propagation behavior. To generate mixed-mode I+II loading state, the compact tension shear(CTS) specimen and loading device were used in this tests. The experimental method divided into three steps and three cases that were step I(0$^{\circ}$), step II(30$^{\circ}$, 60$^{\circ}$, 90$^{\circ}$),step III(0$^{\circ}$) and case I(0$^{\circ}$ ⇒ 30$^{\circ}$ ⇒ 0$^{\circ}$), case II(0$^{\circ}$ ⇒ 60$^{\circ}$ ⇒ 0$^{\circ}$), case III(0$^{\circ}$ ⇒ 90$^{\circ}$ ⇒ 0$^{\circ}$). The result of test, the step II affected to the step III in the all case. Specially, The fatigue crack propagation rate was faster and the fatigue life was smaller than of mixed mode I+II(30$^{\circ}$,60$^{\circ}$) due to the effect of mode II in the step III of the case III

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.2
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• pp.289-295
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• 2001

The aim of this study is to investigate the ductile fracture behaviour under pure Mode II loading using A533B pressure vessel steel. Single punch shear(SPS) test was performed to obtain the J-R curve under pure Mode II loading which was compared with that of the Model I loading. Simulation using Rousellier Ductile Damage Theory(RDDT) was carried out with 4-node quadrilateral element(L(sub)c=0.25mm). For the crack advance, the failed element removal technique was adopted with a $\beta$ criterion. Through the $\beta$ value tuning-up procedures, $\beta$(sub)crit(sup)II was determined as 1.5 in contrast with $\beta$(sub)crit(sup)I=5.5. In conclusion, it was found that the J-R curve under Mode II loading was located at lower part than that under Mode I loading obtained from the previous study and that the $\beta$ values strongly depended on the loading type. In addition, the predicted result using RDDT showed a good agreement with the SPS experimental one under pure Mode II loading.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.49 no.7
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• pp.6-11
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• 2012

A mobile station(MS) in an 802.16e network manages its limited energy using the sleep mode operation. An MS can power down its physical operation components during the unavailability interval of the sleep mode. To reduce energy consumption by increasing the unavailability interval, this paper proposes an enhanced power saving mechanism(ePSM) when both activated Type I and Type II power saving classes(PSCs) exist in an MS. A performance evaluation confirms that ePSM results in the improved performance in terms of the unavailability interval as well as the energy consumption than conventional schemes.

• Journal of the KSME
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• v.32 no.6
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• pp.536-553
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• 1992

하중 종류 중에서 가장 기본적인 하중 중의 하나인 순수 전단력과 순수 굽힘 모멘트를 발생시 키고자 할 때는 아래와 같은 장치를 사용하는 것이 좋다. 1) 등방성체나 이방성체의 횡 전단계수 (G$_{12}$)와 횡 응력 프린지치(f$_{12}$) 등을 측정 하고자 할 때, 또는 모드 II (mode II)상태의 파괴역학을 연구하고자 할 때는 그림 1, 그림 2, 그림 3 그리고 그림 4 등에 제시된 것 중에서 적당한 것을 사용할 수 있다. 그러나 순수 전단 력이 발생되는 면적이 크고, 순수 전단력을 정확하고 균일하게 발생시키고자 할 때, 각 재료의 전단 물성치(shear properties) 측정, 모드II(mode II) 상태의 파괴역학을 연구하고자 할 때는 본 연구자가 고안한 H.I.S.T. 장치를 이용하면 편리하다. 2) 직선 보에 순수 굽힘 모멘트를 균일하고 정확하게 가하고자 할 대는 N.B.M.장치를 사용하는 것이 좋다. 또 N.B.M. 장치는 어느 보의 장치보다도 곡선보나 변형이 큰 보에도 더 정확하고 균일하게 순수 굽힘 모멘트를 발생시킬 수 있다.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.34 no.4
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• pp.450-456
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• 1998

• Proceedings of the Korean Nuclear Society Conference
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• 2001.10a
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• pp.262.1-262
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• 2001

• Journal of the Korean Wood Science and Technology
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• v.20 no.2
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• pp.61-72
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• 1992

This study was carried out to investigate the fracture behavior and the fracture criterion of yellow lauan(Shorea spp.), when has used for furniture and wood structures, and to offer a reliability for wood structure and basic data for wood fracture criterion in experiments which are fracture tested under mode I, mode II and mixed mode loading condition. The results were summarized as follows; 1. Fractures in specimens which have inclined grain in yellow lauan procedeed from crack tip in the radial direction along the grain. 2. In yellow lauan, $K_{IC}RL$ was 42.1kg/$cm^{3/2}$ and $K_{IIC}RL$ was 15.8kg/$cm^{3/2}$. 3. The fracture criteria of lauan were; ($K_I/K_{IC}$)+($K_{II}/K_{IIC}$)=1 in RL system with inclined grain at $45^{\circ}$, ($K_I/K_{IC}$)+$(K_{II}/K_{IIC})^2$=1 with inclined grain at $15^{\circ}$ and $(K_I/K_{IC})^2$+$(K_{II}/K_{IIC})^2$=1 with inclined grain at $30^{\circ}$, $60^{\circ}$, $75^{\circ}$ and $90^{\circ}$, respectively. 4. The fracture criterion of wood could vary with the species, and the load applying condition. In order to measure the fracture criterion strictly, along with standardization of specimen geometry a large amount of experimental data is needed. 5. $K_{IC}$(critical stress intensity factor) can be predicted by grain angle. As the grain inclined angle increased, $K_{IC}$ and $K_{IIC}$ are increased.