• Title/Summary/Keyword: "drop in" Performance test

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Drop Test for the UAV Landing Gear Performance Verification (무인정찰기 착륙장치 성능입증을 위한 낙하시험)

  • Shin, Jeong-Woo;Lee, Seung-Gyu;Yang, Jin-Yeol;Kim, Sung-Joon;Hwang, In-Hee;Chung, Sang-Joon
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2011.10a
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    • pp.250-254
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    • 2011
  • Main role of landing gear is to absorb the energy which is generated by aircraft lanidng and ground maneuvering. Generally, in order to absorb the impact energy during landing, oleo-pneumatic type shock absorber is used for aircraft landing gear. Oleo-pneumatic type shock absorber has a good energy absorbing efficiency and is light in weight because its structure is relatively simple. For the landing gear development, it is necessary to conduct drop test in order to verify shock absorbing performance. In the drop test, first, gas spring curve verification tests are conducted. Then, limit and reserve energy absorption drop tests are performed based on the STANAG 4671. The drop tests results with performance analysis results are presented.

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Drop Performance Test of Conceptually Designed Control Rod Assembly for Prototype Generation IV Sodium-Cooled Fast Reactor

  • Lee, Young-Kyu;Lee, Jae-Han;Kim, Hoe-Woong;Kim, Sung-Kyun;Kim, Jong-Bum
    • Nuclear Engineering and Technology
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    • v.49 no.4
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    • pp.855-864
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    • 2017
  • The control rod assembly controls reactor power by adjusting its position during normal operation and shuts down chain reactions by its free drop under scram conditions. Therefore, the drop performance of the control rod assembly is important for the safety of a nuclear reactor. In this study, the drop performance of the conceptually designed control rod assembly for the prototype generation IV sodium-cooled fast reactor that is being developed at the Korea Atomic Energy Research Institute as a next-generation nuclear reactor was experimentally investigated. For the performance test, the test facility and test procedure were established first, and several free drop performance tests of the control rod assembly under different flow rate conditions were then carried out. Moreover, performance tests under several types and magnitudes of seismic loading conditions were also conducted to investigate the effects of seismic loading on the drop performance of the control rod assembly. The drop time of the conceptually designed control rod assembly for 0% of the tentatively designed flow rate was measured to be 1.527 seconds, and this agrees well with the analytically calculated drop time. It was also observed that the effect of seismic loading on the drop time was not significant.

Influence of design modification of control rod assembly for Prototype Generation IV Sodium-cooled Fast Reactor on drop performance

  • Son, Jin Gwan;Lee, Jae Han;Kim, Hoe Woong;Kim, Sung Kyun;Kim, Jong Bum
    • Nuclear Engineering and Technology
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    • v.51 no.3
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    • pp.922-929
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    • 2019
  • This paper presents the drop performance test of the control rod assembly which is one of the main components strongly related to the safety of the prototype generation IV sodium-cooled fast reactor. To investigate the drop performance, a real-sized control rod assembly that was recently modified based on the drop analysis results was newly fabricated, and several free drop tests under different flow rate conditions were carried out. Then the results were compared with those obtained from the previous tests conducted on the conceptually designed control rod assembly to demonstrate the improvement in performance. Moreover, the drop performance tests under several types and magnitudes of seismic loadings were also conducted to investigate the effect of the seismic loading on the drop performance of the modified control rod assembly. The results showed that the effects of the type and magnitude of the seismic loading on the drop performance of the modified control rod assembly were not significant. Also, the drop time requirement was successfully satisfied, even under the seismic loading conditions.

Drop Performance Test of Control Rod Assembly for Prototype Gen-IV Sodium-cooled Fast Reactor (PGSFR 제어봉집합체 낙하성능시험)

  • Lee, Young Kyu;Kim, Hoe Woong;Lee, Jae Han;Koo, Gyeong Hoi;Kim, Jong Bum;Kim, Sung Kyun
    • Transactions of the Korean Society of Pressure Vessels and Piping
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    • v.12 no.1
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    • pp.134-140
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    • 2016
  • The Control Rod Assembly (CRA) controls the reactor power by adjusting its position in the reactor core during normal operation and should be quickly inserted into the reactor core by free drop under scram condition to shut down chain reactions. Therefore, the drop time of the CRA is one of important factors for the safety of the nuclear reactor and must be experimentally verified. This study presents the drop performance test of the CRA which has been conceptually designed for the Proto-type Generation IV Sodium-cooled Fast Reactor. During the test, the CRA was free dropped from a height of 1 m under different flow rate conditions and its drop time was measured. The results showed that the drop time of the CRA increased as the flow rate increased; the average drop times of the CRA were approximately 1.527 seconds, 1.599 seconds and 1.676 seconds at 0%, 100% and 200% of design flow rates, respectively.

A Study on the/ Correlation Between Board Level Drop Test Experiment and Simulation

  • Kang, Tae-Min;Lee, Dae-Woong;Hwang, You-Kyung;Chung, Qwan-Ho;Yoo, Byun-Kwang
    • Journal of the Microelectronics and Packaging Society
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    • v.18 no.2
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    • pp.35-41
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    • 2011
  • Recently, board level solder joint reliability performance of IC packages during drop impact becomes a great concern to semiconductor and electronic product manufacturers. The handheld electronic products are prone to being dropped during their useful service life because of their size and weight. The IC packages are susceptible to solder joint failures, induced by a combination of printed circuit board (PCB) bending and mechanical shock during impact. The board level drop testing is an effective method to characterize the solder joint reliability performance of miniature handheld products. In this paper, applying the JEDEC (JESD22-B111) standard present a finite element modeling of the FBGA. The simulation results revealed that maximum stress was located at the outermost solder ball in the PCB or IC package side, which consisted well with the location of crack initiation observed in the failure analysis after drop reliability tests.

Pressure Drop and Refrigerant-Entrainment Characteristics of the Eliminators used in Absorption Chillers (흡수식 냉동기용 엘리미네이터의 압력손실 및 액적유입 특성)

  • 정시영;류진상;이상수;이정주
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.15 no.2
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    • pp.109-115
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    • 2003
  • The performance of two vertical-blade eliminators (V1, V2) and two horizontal-blade ones (H1, H2) for absorption chillers were tested in terms of pressure drop and refrigerant entrainment. The test was carried out using a wind tunnel with a cross section of 300 mm$\times$300 mm. The pressure drop of four eliminators tested was found to be in the rage of 1.0~2.7mm $H_2O$ at the face velocity of 2m/s. In the refrigerant entrainment test the vertical-blade eliminators showed much better performance than the horizontal-blade ones. The horizontal-blade eliminators showed satisfactory results at the air velocity of 2m/s but exceeded the limit value at 3 m/s. Since the cooling capacity of a machine is lowered by about 2.5% at the pressure drop of 1 m $H_2O$, more researches are required to reduce the pressure drop in the eliminator.

Performance Test and Evaluation of Ship Exhaust Huffier (선박용 소음기 성능 시험 및 평가)

  • Kim, Bong-Ki;Kim, Sang-Ryul;Kim, Hyun-Sil;Shin, Min-Chol
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2008.11a
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    • pp.158-163
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    • 2008
  • Muffler design in the exhaust system is critical to provide for low noise in shipboard spaces. In an attempt to effectively design the low noise muffler, it is important to evaluate the performance of the muffler considering not only the noise, but also pressure drop as well. For this purpose, a test system of large exhaust muffler for ship propulsion systems was designed based on ISO 7235. The substitution test for determining both the insertion loss and pressure drop of mufflers was carried out. A ship exhaust muffler is considered as a test example and the insertion loss and pressure drop are obtained.

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Performance Test and Evaluation of Ship Exhaust Muffler (선박용 소음기 성능 시험 및 평가)

  • Kim, Bong-Ki;Kim, Sang-Ryul;Kim, Hyun-Sil;Shin, Min-Chol
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.18 no.12
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    • pp.1237-1242
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    • 2008
  • A muffler design in the exhaust system is critical to provide fur low noise in shipboard spaces. In an attempt to effectively design the low noise muffler, it Is important to evaluate the performance of the muffler considering not only the noise, but also pressure drop as well. For this purpose, a test system of large exhaust mufflers fur ship propulsion systems was designed based on ISO 7235. The substitution test fur determining both the insertion loss and pressure drop of mufflers was carried out. A ship exhaust muffler is considered as a test example and the insertion loss and pressure drop were obtained.

Pressure Drop and Leakage Performances of Flat Seals with Inclined Grooves (경사 그루브를 갖는 평판 실의 압력 강하 및 누설 성능)

  • Jung, Jin Woo;Jeong, Gwon Jong;Hwang, Sung Ho;Kim, Tae Ho;Kim, Eojin
    • Tribology and Lubricants
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    • v.38 no.5
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    • pp.213-221
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    • 2022
  • This paper presents performance measurements of pressure drop and leakage flow rate of test flat seals with asymmetric inclined grooves. This study aims to reveal the influence of groove shapes, often machined in radial film riding-face seals, in forming a hydrodynamic wedge on leakage performance. A test facility was developed, and test seals were manufactured to study the effects of the inlet pressure level, ratio of inlet to outlet pressure, seal groove length, and seal groove height on the steady-state pressure drop and leakage performance. A series of tests were conducted, and the test data were compared to the predictions from a simple and efficient mathematical model using a one-dimensional Reynolds equation. The test results revealed that an increase in the inlet pressure increased the pressure drop through the test seals. The leakage flow rate increased significantly as the inlet pressure and ratio of the inlet to outlet pressure increased. The groove shape also affects seal performance. An increase in the groove length and height resulted in an evident increase in the leakage flow rate. The simple model predictions underestimated the leakage flow rates but showed good agreement with the trend in the measurements for all test operating conditions and changes in the groove shape.

The Evaluation of Shock Absorption Performance of Magneto-Rheological Elastomer Through the Drop Impact Test (낙하 충격 실험을 통한 자기유변탄성체의 충격 흡수 성능 평가)

  • Joeng, Kyeong Sik;Lee, Chul Hee
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2013.10a
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    • pp.92-93
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    • 2013
  • In this study, Shock Absorption performance of Magneto-rheological elastomer(MRE) is identified through the drop impact test. Magneto-rheological materials are divided into two groups by MR fluid in fluid state and MR elastomer in solid state like rubber. The stiffness characteristics of Magneto-rheological material can be changed as magnetic field is applied. The impact loads in MR elastomer were measured under weight of impactor. Experiment results are shown through the experiments to confirm the effect of shock absorption of MR elastomer. Thus, the MR elastomer can be applied to shock absorber used in area that shock occurs.

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