• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2007년도 춘계학술대회 논문집
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• pp.434-437
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• 2007

Cold forging technology of a gear product is being interested in the dimensional accuracy, high stiffness and reduction of stress concentration. Especially it is needed to avoid the damage due to extremely high local pressure. Therefore it is important to ensure high pressure in die design. In this study, single die insert type and splitted die insert type are considered to recognize the notch effects in the die of sprocket forming. The stress concentration has been released at the notch area by the cushion effect in the splitted die insert.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.113-115
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• 2007

This paper presents a design notch to reduce cogging torque of interior type permanent magnet motor. As design notch on rotor of IPM motor, magnetic field from between rotor and teeth of state is changed. By reason of variation magnetic field, cogging torque is generated. Through Fourier formulation of magnetic field on rotor, we found position of notch and manufactured armature that is designed by optimizing analysis. The validity of the proposed design is confirmed with experiments.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1996년도 제24회 추계학술대회
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• pp.168-175
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• 1996

This paper reports on theoretical study of the pressure overshoot in the delivery ports and pressure rising within balanced type vane pump. Pressure overshoot occur due to the accelerated fluid through the notch, so, result in pressure ripple, flow ripple, and noise. For calculating the pressure rising and fluctuations of pressure, we have modeled mathematically used continuity equation based on compressibility and momentum equation considered fluid inertia in the notch, and analyzed simultaneously. As a results of analysis, we have found oscillation of pressure and compression chamber pressure depend on the rotational speeds, bulk modulus of working fluid, notches, number of vane and camring. Using the model, notches have been shown to be important design factor in relaxing the rapid pressure rising and reducing the amplitudes of pressure overshoot.

• 소성∙가공
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• 제16권6호
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• pp.452-456
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• 2007

Cold forging technology of a gear product is being interested in the dimensional accuracy, high stiffness and reduction of stress concentration. Especially it is needed to avoid the damage due to extremely high local pressure. Therefore it is important to reduce the high pressure in die design of cold forging. In this study, single die insert type and splitted die insert type are considered to recognize the notch effects in the die of sprocket forming. The stress concentration has been released at the notch area by the cushion effect in the splitted die insert.

• 한국가스학회지
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• 제27권2호
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• pp.95-103
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• 2023

본 논문에서는 가스압력을 고려할 때 수소가스 저장용기(Type 1)의 거동특성을 평가하기 위해 ISO 18119의 노치형상에 따라 수소가스 저장용기에서 발생한 VMS(von Mises stress)을 유한요소법으로 해석하였다. 해석결과에 따르면 길이방향 노치에서 발생한 최대 VMS가 원주방향 노치보다 높게 발생하였다. 또한, 저장용기의 거동시 발생한 응력을 VMS와 재료의 항복강도 비인 응력비로 분석하였다. 해석결과에 따르면 노치가 길이방향으로 형성된 저장용기의 경우 가스압력 50 MPa에서 저장용기 내부와 외부가 각각 0.85와 0.50로 증가하였으나 1보다 낮게 분석되었다.

• 드라이브 ㆍ 컨트롤
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• 제13권3호
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• pp.39-46
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• 2016

Flow and pressure ripple in swash plate type piston pumps is largely dependent on the design of notches(silencing grooves) in the valve plate. In uni-directional pumps, the basic design concept for notches in the valve plate could be said to be established. It is easily deduced that the design concept for notches in uni-directional pumps can not be simply applied to bi-directional pumps requested for EHA(electric hydrostatic actuators). To carry out systematic research on technological issues regarding notch applications to bi-directional piston pumps, five notch designs are devised. The effects of the notch designs on the characteristics of the pump are investigated by numerical simulations and experiments. Through this study, basic concepts about notch design for bi-directional piston pumps are suggested.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 춘계학술대회 논문집
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• pp.533-539
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• 1997

Pressure ripple of hydraulic vane pump results form flow ripple due to pump geometry and reverse flow through the discharge port due to compressibility of fluid and result in vibration and noise of connected hydraulic elements. In a ba;anced type vane pump, cam ring curve is important factor to influence the flow ripple. Therefore, to reduce the now ripple, it has been required that optimal selection of seal region by proper design of cam ring and each port position, and notches for preventing the excessive reverse flow. This paper has been performed analytical study of compression characteristics with major design parameter in side plate and cam ring, and examined into the role of notch and radius reduction ratio.

• 한국정밀공학회지
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• 제15권1호
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• pp.87-93
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• 1998

Pressure ripples of hydraulic vane pump results from flow ripples due to pump geometry and reverse flow through the discharge port due to compressibility of fluid and result in vibration and noise of connected hydraulic elements. In a balanced type vane pump, cam ring curve is important factor to influence the flow ripples. Therefore, to reduce the flow ripple, it has been required that optimal selection of seal region by proper design of cam ring and each port position, and notches for preventing the excessive reverse flow. This paper has been performed analytical study of compression characteristics with major design parameter in side plate and cam ring. and examined into the role of notch and radius reduction ratio.

• Nuclear Engineering and Technology
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• 제54권5호
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• pp.1588-1596
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• 2022

In the nuclear power plants, stainless steel is widely used for fabrication of various components such as piping and pipe fittings. These piping components are subjected to cyclic loading due to start up and shut down of the nuclear power plants. The application of cyclic loading may lead to initiation of crack at stress raiser locations such as nozzle to piping connection, crown of piping bends etc. of the piping system. Crack initiation can also take place from the flaws which have gone unnoticed during manufacturing. Therefore, prediction of crack initiation life would help in decision making with respect to plant operational life. The primary objective of the present study is to compile various analytical models to predict the crack initiation life of the pipes with notch. Here notch simulates the stress raisers in the piping system. As a part of the study, Coffin-Manson equations have been benchmarked to predict the crack initiation life of pipe with notch. Analytical models proposed by Zheng et al. [1], Singh et al. [2], Yang Dong et al. [25], Masayuki et al. [33] and Liu et al. [3] were compiled to predict the crack initiation life of SA312 Type 304LN stainless steel pipe with notch under fatigue loading. Tensile and low cycle fatigue properties were evaluated for the same lot of SA312 Type 304LN stainless steel as that of pipe test. The predicted crack initiation lives by different models were compared with the experimental results of three pipes under different frequencies and loading conditions. It was observed that the predicted crack initiation life is in very good agreement with experimental results with maximum difference of ±10.0%.

• 한국기계가공학회지
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• 제17권4호
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• pp.104-112
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• 2018

Considering the shape of a valve plate in design is important for reducing the pulsation phenomenon, which is a negative factor in pump performance. The purpose of this study is to propose an optimized method for a valve-plate V-type notch of a piston pump by modeling and simulation. The method uses $SimulationX^{(R)}$, a commercial hydraulic analysis program, and to provide data for the designing of the notch. The opening areas are determined by performing kinematic analysis of the notch part where the opening area changes rapidly. After applying the result analysis, the main effects on maximum pressure pulsation and maximum backflow according to the notch design factors are analyzed by using the full factorial method of experimental design. The optimized solutions are derived for the notch design variables, based on the analyzed data.