• Title/Summary/Keyword: simulations analysis

Search Result 4,305, Processing Time 0.026 seconds

Size and Shape Optimization of the Oil Pump for Fuel Consuming Reduction (엔진 연비 향상을 위한 오일펌프 사이즈/형상 최적화)

  • Jo, Sok-Hyun;Nam, Kyung-Woo
    • Transactions of the Korean Society of Automotive Engineers
    • /
    • v.16 no.1
    • /
    • pp.22-28
    • /
    • 2008
  • Generally block imbedded type oil pump is adopted to make a small engine. In this paper 1D/3D numerical simulations were conducted to reduce energy consumption of the block imbedded type oil pump. At each stage of engine development we have estimated the oil flow rate and pressure to optimize oil pump sizes by using the 1D system analysis and then accomplished 3D CFD(Computational Fluid Dynamics) simulations to optimize oil pump shapes including inlet/outlet port. As a result, the energy consumption of oil pump has been reduced to nearly 27% and the engine fuel consumption to $1{\sim}1.5%$.

Steel processing effects on crash performance of vehicle safety related applications

  • Doruk, Emre
    • Steel and Composite Structures
    • /
    • v.24 no.3
    • /
    • pp.351-358
    • /
    • 2017
  • Due to the increasing competition, automotive manufacturers have to manufacture highly safe and light vehicles. The parts which make up the body of the vehicle and absorb the energy in case of a crash, are usually manufactured with sheet metal forming methods such as deep drawing, bending, trimming and spinning. The part may get thinner, thicker, folded, teared, wrinkled and spring back based on the manufacturing conditions during manufacturing and the type of application methods. Transferring these effects which originate from the forming process to the crash simulations that are performed for vehicle safety simulations, makes accurate and reliable results possible. As a part of this study, firstly, the one-step and incremental sheet metal forming analysis (deep drawing + trimming + spring back) of vehicle front bumper beam and crash boxes were conducted. Then, crash performances for cases with and without the effects of sheet metal forming were assessed in the crash analysis of vehicle front bumper beam and crash box. It was detected that the parts absorbed 12.89% more energy in total in cases where the effect of the forming process was included. It was revealed that forming history has a significant effect on the crash performance of the vehicle parts.

PERFORMANCE ANALYSIS OF HOVERING UH-60A ROTOR BLADE (UH-60A 로터 블레이드의 정지비행 성능해석)

  • Park, Y.M.;Chang, B.H.;Chung, J.D.
    • 한국전산유체공학회:학술대회논문집
    • /
    • 2007.10a
    • /
    • pp.73-76
    • /
    • 2007
  • The present paper describes the results of performance analysis for UH-60A rotor blade in hover. For the numerical simulations, commercial CFD software, FLUENT was used with Spalart-Allmaras turbulence model. The flow solver was based on node based scheme and second order spatial accuracy options was used for simulations. For the enhancement of wake capturing capability, high resolution grid was used around tip vortex region. Granting that somewhat over prediction of thrust was observed near blade tip region, performance was well correlated with experimental data within 3% accuracy in the operating region. Finally it was shown that the present flow solver can be used for preliminary performance analysis tool for hovering helicopter rotor blades.

  • PDF

IMPROVEMENT OF FLOW SIMULATIONS METHOD WITH MULTI-RESOLUTION ANALYSIS BY BOUNDARY TREATMENT (경계면 처리 개선을 통한 다중해상도 유동해석 기법 개선 연구)

  • Kang, H.M.
    • Journal of computational fluids engineering
    • /
    • v.20 no.4
    • /
    • pp.44-50
    • /
    • 2015
  • The computational efficiency of flow simulations with Multi-resolution analysis (MRA) was enhanced via the boundary treatment of the computational domain. In MRA, an adaptive dataset to a solution is constructed through data decomposition with interpolating polynomial and thresholding. During the decomposition process, the basis points of interpolation should exceed the boundary of the computational domain. In order to resolve this problem, the weight coefficients of interpolating polynomial were adjusted near the boundaries. By this boundary treatment, the computational efficiency of MRA was enhanced while the numerical accuracy of a solution was unchanged. This modified MRA was applied to two-dimensional steady Euler equations and the enhancement of computational efficiency and the maintenance of numerical accuracy were assessed.

On the Suitability of Centered and Upwind-Biased Compact Difference Schemes for Large Eddy Simulations (III) - Dynamic Error Analysis - (LES에서 중심 및 상류 컴팩트 차분기법의 적합성에 관하여 (III) -동적 오차 해석 -)

  • Park, No-Ma;Yoo, Jung-Yul;Choi, Hae-Cheon
    • Transactions of the Korean Society of Mechanical Engineers B
    • /
    • v.27 no.7
    • /
    • pp.995-1006
    • /
    • 2003
  • The suitability of high-order accurate, centered and upwind-biased compact difference schemes for large eddy simulation is evaluated by a dynamic analysis. Large eddy simulation of isotropic turbulence is performed with various dissipative and non-dissipative schemes to investigate the effect of numerical dissipation on the resolved solutions. It is shown by the present dynamic analysis that upwind schemes reduce the aliasing error and increase the finite differencing error. The existence of optimal upwind scheme that minimizes total numerical error is verified. It is also shown that the finite differencing error from numerical dissipation is the leading source of numerical errors by upwind schemes. Simulations of a turbulent channel flow are conducted to show the existence of the optimal upwind scheme.

Analysis of Deformation and Microstructural Evolution during ECAP Using a Dislocation Cell Related Microstructure-Based Constitutive Model (전위쎌에 기초한 미세조직 구성모델을 이용한 ECAP 공정 시 변형과 미세조직의 진화 해석)

  • Kim H. S.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
    • /
    • 2004.10a
    • /
    • pp.207-210
    • /
    • 2004
  • The deformation behavior of copper during equal channel angular pressing (ECAP) was calculated using a three-dimensional version of a constitutive model based on the dislocation density evolution. Finite element simulations of the variation of the dislocation density and the dislocation cell size with the number of ECAP passes are reported. The calculated stress, strain and cell size are compared with the experimental data for Cu deformed by ECAP in a modified Route C regime. The results of FEM analysis were found to be in good agreement with the experiments. After a rapid initial decrease down to about 200 nm in the first ECAP pass, the average cell size was found to change little with further passes. Similarly, the strength increased steeply after the first pass, but tended to saturate with further pressings. The FEM simulations also showed strain non-uniformities and the dependence of the resulting strength on the location within the workpiece.

  • PDF

Resource Demand/Supply and Price Forecasting -A Case of Nickel- (자원 수급 및 가격 예측 -니켈 사례를 중심으로-)

  • Jung, Jae-Heon
    • Korean System Dynamics Review
    • /
    • v.9 no.1
    • /
    • pp.125-141
    • /
    • 2008
  • It is very difficult to predict future demand/supply, price for resources with acceptable accuracy using regression analysis. We try to use system dynamics to forecast the demand/supply and price for nickel. Nickel is very expensive mineral resource used for stainless production or other industrial production like battery, alloy making. Recent nickel price trend showed non-linear pattern and we anticipated the system dynamic method will catch this non-linear pattern better than the regression analysis. Our model has been calibrated for the past 6 year quarterly data (2002-2007) and tested for next 5 year quarterly data(2008-2012). The results were acceptable and showed higher accuracy than the results obtained from the regression analysis. And we ran the simulations for scenarios made by possible future changes in demand or supply related variables. This simulations implied some meaningful price change patterns.

  • PDF

Dynamic Analysis of Jerking in Push-Pull Type Train (Push-Pull Type 철도차량 Jerking 현상 해석)

  • 김영준;박상규
    • Proceedings of the KSR Conference
    • /
    • 1998.05a
    • /
    • pp.502-509
    • /
    • 1998
  • The scheme to reduce jerking phenomena in one push-pull type trainset was proposed. To simulate the jerking between coaches, dynamic analysis model was made. This model could analyze longitudinal dynamic behavior between locomotives and coaches caused by spring and damping characteristics of couplers and center pivots; characteristic curves of traction and braking. To validate the analysis results, tests were conducted in the same driving and braking condition. Comparison of longitudinal acceleration between simulation and test results shows a good agreement. To minimize the jerking phenomena, lots of dynamic simulations were conducted with varying driving/braking effort curve. From the results of simulations, an efficient and economic way to reduce jerking phenomena was found to be to reduce slope of tractive effort curve and synchronize braking time between locomotives and coaches. Test results show that this way could reduce the jerking Phenomena. To express jerkins Phenomena quantitatively, maximum peak to peak values of acceleration were used.

  • PDF

A New Interpretation Approach using Tobit Analysis : Simulations based on Type I Tobit of Amemiya - Focused on Childcare Services -

  • Park, Sun-Young
    • Journal of Families and Better Life
    • /
    • v.19 no.6
    • /
    • pp.145-155
    • /
    • 2001
  • The purposes of this study were first to construct statistical and econometric models based on Amemiya\`s Type I Tobit mainly addressing the issue of statistical efficiency; second to explore income, price, and curvilinear age effects on the explained variable in order to illustrates its statistical marginal effects related to econometric issues; finally to provide invaluable insight for graphical simulations as a new interpretation approach using Tobit analysis. Results indicated that interpretation for the mean marginal effects of three possible cases of dependent variable was more likely to be evident to understand Tobit results compared to conventional analysis only using latent variable, beta. Results also revealed that prediction value of dependent variable can be possibly and easily projected by the independent variable changed whereas only beta value can not illustrate its projection as independent variables'changes.

  • PDF

The Development of Torpedo Defense Experimental Technique based on M&S (M&S 기반 어뢰방어전 모의실험 기술 구현)

  • Nah, Young-In;Lee, Sim-Yong;Yoon, Han-Saem
    • Journal of the Korea Institute of Military Science and Technology
    • /
    • v.13 no.5
    • /
    • pp.818-823
    • /
    • 2010
  • Exploiting models and simulations are encouraged among the defense acquisition society, as now enforced by the Defense Aquisition Program Administration's regulations. They are useful and, sometimes, inevitable especially in an earlier phase of system development. Computer-simulation-based experimentation technique for the system operational performance analysis for a torpedo defense system is introduced in this paper. Problem definition for the torpedo defense system analysis and engineering efforts for models and simulations development are presented here, including defining measures of performance and effectiveness for the torpedo defense system, conceptual modeling for torpedo engagement and defense simulation, design of experimentation, design of simulator and experimentor, and hardware and software implementation of an analysis support tool - a system operations demonstration and experimentation simulator.