• Title/Summary/Keyword: drop ball method

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Experimental Study on the Internal Flow of a Ball Valve used for a Gas Pipeline (가스 파이프라인용 볼 밸브 내부유동의 실험적 연구)

  • KIM, CHUL-KYU;LEE, SANG-MOON;JANG, CHOON-MAN
    • Journal of Hydrogen and New Energy
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    • v.27 no.3
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    • pp.311-317
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    • 2016
  • This paper presents the flow characteristics of a ball valve used for a gas pipeline. Understanding of the internal flow of a ball valve is an important to analyze the physical phenomena of the valve. Present experimental study was performed by IEC 60534-2-3, the international standard for an industrial control valve testing procedure. Pressure measured at upstream and downstream of the valve, flow-rate and gas temperature passing the inside of the gas pipeline were measured with respect to valve opening rates. Throughout the experimental measurement of the ball valve, empirical equation of the pressure drop between the ball valve according to the mass flow rates is successively obtained using a polynomial curve fitting method. In addition, flow coefficient for determining the valve capacity is also analyzed with respect to valve opening rates using the curve fitting method.

A Study on Toughened Glass Used for Vehicles and Its Testing Methods (자동차용 강화유리와 그 시험방법에 대한 연구)

  • Ahn, Ho-soon;Kwon, Hea-boung;Lee, Kwang-bum;Jeon, Sang-woo;Son, Young-san
    • Journal of Auto-vehicle Safety Association
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    • v.7 no.3
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    • pp.14-18
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    • 2015
  • Toughened glass is known to have about four times larger external impact resistance than that of original glass. This study is aimed to verify that ceramic-printed toughened glass does not meet of GTR(Global Technical Regulations) No. 6 and its strength is lower than that of original glass through tests. The tests were conducted on the test pieces of original glass, toughened glass, and ceramic-printed toughened glass from five glass manufacturers. In Test 1, a 227g steel ball was dropped from a height of 2 meters, and damage was checked according to the test method of GTR No. 6. In Test 2, a steel ball was freely dropped from different heights and limited damage height was determined. In the result of Test 1 according to the test method of GTR No. 6, while all five test pieces of toughened glasses were not damaged, all the ceramic-printed toughened glass from the five manufacturers were damaged. In the result of Test 2, none of the five test pieces of toughened glass were damaged by a 10m ball drop, meanwhile, the original glasses were damaged by an average of 3m ball drop. And the results of the tests show that the ceramic-printed toughened glass does not have the features of toughened glass due to its very low strength. Therefore, this study contributes to the safety of consumers by considering the GTR No. 6, and by revising the toughened glass test method.

Engineering Characteristics Assessment of Rapid Set Controlled Low Strength Material for Sewer Pipe Using Excavated Soil (굴착토를 활용한 속경성 유동성 채움재의 공학적 특성 평가)

  • Kim, Young-Wook;Lee, Bong-Chun;Jung, Sang-Hwa
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.8 no.4
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    • pp.450-457
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    • 2020
  • In this study, engineering characteristics such as flowability, segregation and compressive strength by age to derive fast hardening material mixing proportion using excavated soil. And based on optimal mixing proportion, field simulation experiment conducted in laboratory to examine the effectiveness of the method such as kelly ball drop test and soil penetration test for reviewing the following process. As as a result of evaluation, in case of kelly ball drop test and soil penetration test were securing the following process initiation time 3 hours after place CLSM. As results of these assessments, kelly ball drop test and soil penetration test were applicable for revewing following process in construction field besides unconfined compressive strength method.

Shear and impact strength of waste plastic fibre reinforced concrete

  • Karanth, Savithri S;Ghorpade, Vaishali G;Rao, H Sudarsana
    • Advances in concrete construction
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    • v.5 no.2
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    • pp.173-182
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    • 2017
  • This paper is aimed at determining the shear and impact strength of waste plastic fibre reinforced concrete. M30 grade of concrete is prepared with waste plastic door fibres cut into 5 mm width and aspect ratios of 30, 50, 70, 90 and 110. Fibres are used in a volume fraction of 0 to 1.5% with an increment of 0.25%. L shaped specimens are cast for shear strength tests and flat plates of size $250{\times}250{\times}30mm$ are used for impact tests. "Drop ball method" is used for checking the impact strength. Shear strength is checked with L shaped specimens under UTM with a special attachment. It was found that up to 1.25% of waste plastic fibres can be effectively used for better strength of concrete both in shear and impact. Shear and impact strength were found to be increasing up to a volume fraction of fibres of 1.25%.

Prediction of Impact Life Time in Solder Balls of the Board Level Flip Chips by Drop Simulations (낙하해석을 통한 보드 레벨 플립칩에서의 솔더볼 충격수명에 관한 연구)

  • Jang, Chong Min;Kim, Seong Keol
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.23 no.3
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    • pp.237-242
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    • 2014
  • Recently much research are has been done into the compositions of lead-free solders. As a result, there has been a rapid increase in the number of new compositions. In the past, the properties of these new compositions were determined and verified through drop-impact tests. However, these drop tests were expensive and it took a long time to obtain a result. The main goal of this study was to establish an analytical method capable of predicting the impact life-time of a new solder composition for board-level flip chips though the application of drop simulations using LS-DYNA. Based on the reaction load obtain with LS-DYNA, the drop-impact fracture cycles were predicted. The study was performed using a Sn-3.0Ag-0.5Cu solder (305 composition). To verify the reliability of the proposed analytical method, the results of the drop-impact tests and life-time analysis were compared, and were found to be in good agreement. Thus, the new analytical method was shown to be very useful and effective.

Board-Level Drop Analyses having the Flip Chips with Solder balls of Sn-3.0Ag-0.5Cu and Sn-1.0Ag-0.5Cu (Sn-3.0Ag-0.5Cu 및 Sn-1.0Ag-0.5Cu 조성의 솔더 볼을 갖는 플립칩에서의 보드레벨 낙하 해석)

  • Kim, Seong-Keol
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.20 no.2
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    • pp.193-201
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    • 2011
  • Recently, mechanical reliabilities including a drop test have been a hot issue. In this paper, solder balls with new components which are Sn-3.0Ag-0.5Cu and Sn-1.0Ag-0.5Cu-0.05N are introduced, and board level drop test for them are conducted under JEDEC standard in which the board with 15 flip chips is dropped as 1,500g acceleration during 0.5ms. The drop simulations are studied by using a implicit method in the ANSYS LS-DYNA, and modal analysis is made. Through both analyses, the solder balls with new components are evaluated under the drop. It is found that the maximum stress of each chip is occurred between the solder ball and the PCB, and the highest value among the maximum stresses in the chips is occurred on the chip nearest to fixed holes on the board in the drop tests and simulations.

Porous concrete with optimum fine aggregate and fibre for improved strength

  • Karanth, Savithri S.;Kumar, U. Lohith;Danigond, Naveen
    • Advances in concrete construction
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    • v.8 no.4
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    • pp.305-309
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    • 2019
  • Pervious concrete pavements are the need of the day to avoid urban flooding and to facilitate ground water recharge. However, the strength of pervious or porous concrete is considerably less compared to conventional concrete. In this experimental investigation, an effort is made to improve the strength of pervious concrete by adopting fibres and a small amount of fine aggregate. A porous concrete with cement to aggregate ratio of 1:5 and a water-powder ratio of 0.4 is adopted. 30% of the cement is replaced by cementitious material ground granulated blast furnace slag (GGBS) for better strength and workability. Recron fibres at a dosage of 0.5, 1.0 and 1.5% by weight of cement were included to improve the impact strength. Since concrete pavements are subjected to impact loads, the impact strength was also calculated by "Drop ball method" in addition to compressive strength. The effect of fine aggregate and recron fibres on workability, porosity, compressive and impact strength was studied. The investigations have shown that 20% inclusion of fine aggregate and 1.5% recron fibres by weight of cement give better strength with an acceptable range of porosity.

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.

A study on efficient machining of smooth drafting surface using CAM software (CAM 소프트웨어를 활용한 완만한 구배면의 효율적인 가공에 관한 연구)

  • Park, Hee-Su;Choi, Kye-Kwang
    • Design & Manufacturing
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    • v.13 no.3
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    • pp.19-23
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    • 2019
  • In the mold industry, CAM software has been introduced to solve the impossible or time-consuming part of the mold industry because the increase in labor costs, the drop in mold price, and the short delivery time are tasks to be solved not only in the manufacturing industry but also in the mold industry as a whole. In order to reduce the processing time and improve the surface roughness, we have been conducting various researches for efficient machining. This study was carried out to compare the ball end mill and radius end mill tools with the Power mill software and NC brain software under the same conditions and to find out the most efficient method of machining the smooth drafting surface and improving the surface roughness. (1) By machining the smooth drafting surface using radius end mill, the machining time is 23.7% faster than when using ball end mill. (2) Surface roughness when machined with radius end mill is smoother than when using ball end mill. Based on these results, it can not be applied to all shapes, but if it is a relatively wide and simple gradient shape, the raster machining method using radius end mill can be more effective in terms of delivery and quality than machining with ball end mill.

Board Level Drop Simulations and Modal Analysis in the Flip Chips with Solder Balls of Sn-1.0Ag-0.5Cu Considering Underfill (언더필을 고려한 Sn-1.0Ag-0.5Cu 조성의 솔더볼을 갖는 플립칩에서의 보드레벨 낙하 및 진동해석)

  • Kim, Seong-Keol;Lim, Eun-Mo
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.21 no.2
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    • pp.225-231
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    • 2012
  • Drop simulations of the board level in the flip chips with solder joints have been highlighted for years, recently. Also, through the study on the life prediction of thermal fatigue in the flip chips considering underfill, its importance has been issued greatly. In this paper, dynamic analysis using the implicit method in the Finite Element Analysis (FEA) is carried out to assess the factors effecting on flip chips considering underfill. The design parameters are size and thickness of chip, and size, pitch and array of solder ball with composition of Sn1.0Ag0.5Cu. The board systems by JEDEC standard is modeled with various design parameter combinations, and through these simulations, maximum yield stress and strain at each chip are shown at the solder balls. Modal analysis is simulated to find out the relation between drop impact and vibration of the board system.