• Title/Summary/Keyword: test cost reduction

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A Study on the Corrosion Resistance of Hot Stamped Automotive Parts (자동차 열간 프레스 가공 부품의 내식성에 관한 연구)

  • Yoo, Ji-Hong;Nam, Seung-Man
    • Transactions of the Korean Society of Automotive Engineers
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    • v.18 no.5
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    • pp.25-30
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    • 2010
  • The authors have studied on the corrosion resistance of the hot stamped steel sheets for the application to automotive parts. Recently automotive companies have focused on the hot stamped parts to meet the light weighting needs and the safe reason. Because of the cost reduction of the hot stamped parts, automotive companies increase the usage of the coated steel sheets, especially Al-Si coated steel sheets. The coated layer of Al-Si coated steel sheets contains up to 50% of Fe, which was diffused from the steel sheet, after hot stamping. The hot stamped steel sheet was not phosphated due to the oxidation layer of the coating, however, the result of the water resistance test is similar to that of the conventional GA steel sheets. The pitting depth and the weight reduction of the coated layer of hot stamped steel sheets are less than those of GA steel.

The Characteristics of Engine Noise and its Reduction Techniques (엔진 소음, 진동 특성 및 개선방안)

  • 이재갑;여승동
    • Journal of KSNVE
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    • v.7 no.4
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    • pp.689-700
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    • 1997
  • There are many difficulties in designing the engine structure properly due to the strong conflicts between NVH characteristics and the high performance, light weight and low product cost. Many feasible noise reduction techniques should be carefully incorporated to meet such stringent noise requirements. It is also required that the engine development be carried out by introducing concurrent engineering, in which the analysis and test database are usefully applied to the detail designs from the 1st stage. This paper reviews the significance of the noise characteristics of the structure elements in relation to the combustion pressure. The mechanisms of the crank shaft rumbling, which is the main source having the bad influence on the sound quality, are also explained. The influences of dynamic behavior of engine structure on its noise are investigated, followed by discussions on experimental results of the features necessary for the design of low noise engine concepts.

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A Development of Sound Encloser for Breaker to reduce Construction Noise (건설현장 소음저감을 위한 건설장비용 방음덮개 개발)

  • Jang, Jae-Hee;Jeong, Jae-Kuk
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2000.06a
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    • pp.177-182
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    • 2000
  • This study aims to provide an effective method to reduce construction noise generated by breakers. To reduce the breaker's noise level, a sound encloser was developed; the sound insulation's performance was tested in the field. From the field test, the following results were obtained. The sound insertion loss was about 6.5dB(A), even though part of the sound encloser for the breaker was left unclosed. This is equal to the reduction value which can be obtained by using more expensive low noise breakers, proving that there are more effective measures for sound insulation at lower cost. The characteristic of frequency was evaluated to show an even reduction through all frequency bands, except 630Hz.

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Evaluation of Servo Press Slide Motion for Springback Reduction of High Strength Steel (고장력강판의 스프링백 저감을 위한 서보프레스 슬라이드모션 평가)

  • Song, J.S.;Youn, K.T.;Park, C.D.;Heo, J.Y.;Kim, Y.H.
    • Transactions of Materials Processing
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    • v.26 no.5
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    • pp.277-285
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    • 2017
  • Vehicle weight reduction is a known strategy to improve fuel efficiency and strengthen exhaust gas regulation. The use of high strength steel can satisfy safety, efficiency, emission, manufacturability, durability, and cost requirements. However, springback of high strength steel results in undesired shape defects. Springback is one of the most important issues of high strength steel for many applications in an automobile. Servo press has various capabilities to improve defects, process conditions, and productivity problems when forming a high strength steel. Especially, servo press can be set to function with variable slide motion in a single operation. In this study, the effect of servo press slide motion on 980MPa high strength steel was investigated through U-bending test.

Study of Durability Effect Parameter in Inserting Bush into Suspension Link (서스펜션 링크의 부시 압입에 따른 내구 영향도 연구)

  • Lee, Kyusik
    • Journal of Applied Reliability
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    • v.17 no.2
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    • pp.143-149
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    • 2017
  • Purpose: In recent years, weight reduction for improving fuel efficiency of the vehicle and cost reduction have been developed. The structure of suspension link is widely used as a single plate press structure which can reduce process and weight compared to existing pipe welding method. However, it was found that the lifetime of a single plate press structure is determined by initial defects that occurred during initial manufacturing rather than fatigue damage caused by driving. Methods: I research the mechanism of failure phenomenon of the single plate press assist arm of rear wheel. In addition, I investigate durability effect parameters to determine the link lifetime in inserting bush into single plate press process through durability test. Conclusion: I discover significant durability effect parameter in inserting bush into single plate press process. It is expected that the durability can be improved by suggesting a bush inserting process inspection guide for similar suspension link like single plate press structure.

A Study on the Influece of Residual Stresses on Fatigue Crack Growth Behaviors in the Weldment Plate with Various Thickness (변후 용접판재에서의 피로균열성장거동에 미치는 잔류응력의 영향에 관한 파괴역학적 연구)

  • 차용훈
    • Journal of the Korean Society of Safety
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    • v.8 no.1
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    • pp.71-79
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    • 1993
  • The welding implementation used widely in the industrial field is gradually increasing due to weight reduction. unlimited material thickness. simplified structure design. and 1 manufacturing time and cost reduction. The most significant factor that influences the fatigue crack growth rate is the residual stress generated during the welding process. Many researchers have studied the effect of the residual stress on crack growth behavior. Through a fatigue test in a various-thickness welded specimen. redistributed residual stress is measured as the crack is developed. Then. by superposing the measured residual stress on the K value obtained by the finite element method.

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Remodeling of tuna purse seiner for improving fishing performance (조업성능 향상을 위한 선망선 개선)

  • Hong, Jin-Keun;Kang, Il-Kwon;Jeong, Seong-Jae
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.47 no.4
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    • pp.435-442
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    • 2011
  • In an attempt to respond to the increase in international oil prices and reduce operating expenses, ship remodeling was carried out on a 740ton class tuna purse seiner. To strengthen the competitiveness of the fisheries industry by improving vessel performance, a bulbous bow was newly equipped. The slipway and rudder area were also lengthened and enlarged with the propeller and main engine remained unchanged. To reduce the hull resistance, a circle type bulbous bow was attached on the hull behind bow thruster and thus the cost for exchanging electrical equipment for bow thruster was reduced. The new rudder area was expanded 15% more than the old one within the extent that the existing mechanical control part and rudder stock were not changed. To prevent fishing net damage and stabilize wake field, slipway was lengthened to the optimal position. All of the new design of remodeling parts went through the model tests in towing tank and CWC. Besides resistance test, all of necessary model test results were delivered for hydrodynamic character for the modified ship. The maneuvering simulation to verify that the remodeled ship satisfies the IMO rules was performed in both zigzag and turning tests. The estimated resistance with new bulbous bow and lengthened stern was reduced by 4.8% in the 2-dimensional analysis and 17.4% in the 3-dimensional analysis in comparison of conventional ship. The average reduction of resistance was estimated about 10%. Maneuvering character of modified hull form was found to satisfy all regulations under IMO. The remodeling of tuna purse seiner can not only improve fishing performance but also contribute to reduction of operating cost by saving energy for the fisheries industry.

Feasibility study on the wide and long 9%Ni steel plate for use in the LNG storage inner tank shell

  • Chung, Myungjin;Kim, Jongmin;Kim, Jin-Kook
    • Steel and Composite Structures
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    • v.32 no.5
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    • pp.571-582
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    • 2019
  • This study aimed to assess the feasibility on the wide and long 9%Ni steel plate for use in the LNG storage inner tank shell. First, 5-m-wide and 15-m-long 9%Ni steel plates were test manufactured from a steel mill and specimens taken from the plates were tested for strength, toughness, and flatness to verify their performance based on international standards and design specifications. Second, plates with a thickness of 10 mm and 25 mm, a width of 4.8~5.0 m, and a length of 15 m were test fabricated by subjecting to pretreatment, beveling, and roll bending resulting in a final width of 4.5~4.8 m and a length of 14.8m with fabrication errors identical to conventional plates. Third, welded specimens obtained via shield metal arc welding used for vertical welding of inner tank shell and submerged arc welding used for horizontal welding were also tested for strength, toughness and ductility. Fourth, verification of shell plate material and fabrication was followed by test erection using two 25-mm-thick, 4.5-m-wide and 14.8-m-long 9%Ni steel plates. No undesirable welding failure or deformation was found. Finally, parametric design using wide and long 9%Ni steel plates was carried out, and a simplified design method to determine the plate thickness along the shell height was proposed. The cost analysis based on the parametric design resulted in about 2% increase of steel weight; however, the construction cost was reduced about 6% due to large reduction in welding work.

Economic Analysis of Two-Layer Quiet Asphalt Pavement Considering Noise Cost Benefits (소음 편익 비용을 고려한 복층 저소음 아스팔트 포장의 경제성 분석)

  • Kang, Haet Vit;Park, Ki Sun;Kim, Nak Seok
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.34 no.5
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    • pp.1581-1587
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    • 2014
  • Two-lalyered quiet asphalt pavements are well known for their noise reduction capabilities compared to the conventional ones. This study was conducted to analyze the economic effects on two-layered quiet asphalt pavement rather than on one-layered. Noise prediction was performed on the data surveyed from the two-layered quiet asphalt pavement. In addition, the economic analysis was executed considering cost benefits using the noise prediction result. The permeability test was also investigated to evaluate the clogging recovery of two-layered quiet asphalt pavement. Analysis results revealed that the construction cost of two-layered quiet asphalt pavements was cheaper than that of the conventional soundproof walls. The two-layered quiet asphalt pavement with simulated clogging conditions was satisfied the permeability requirements of the permeable asphalt pavements. The permeability test results showed that the permeable time was recorded as 6.77 seconds for one cycle of cleaning job with 400 mL of water.

Development of Low-Cost Automatic Flight Control System for an Unmanned Target Drone (무인표적기용 저가형 자동비행시스템 개발)

  • Lee, Jang-Ho;Ryu, Hyeok;Kim, Jae-Eun;Ahn, Iee-Ki
    • Journal of Advanced Navigation Technology
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    • v.8 no.1
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    • pp.19-26
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    • 2004
  • This paper deals with the automatic flight control system for an unmanned target drone which is operated by an army as an anti-air gun shooting training. By automation of unmanned target drone that is manually operated by external pilot, pilot can reduce workload and an army can reduce the budget. Most UAVs which are developed until today use high-cost sensors as AHRS and IMU to measure the attitude, but those are contradictory for the reduction of budget. This paper says the development of low-cost automatic flight control system which makes possible of automatic flight with low-cost sensors. We have developed the integrated automatic flight control system by integrating electricity module, switching module, monitoring module and RC receiver as an one module. We also prove the performance of automatic flight control system by flight test.

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