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舰空导弹发射模型研究 总被引:1,自引:0,他引:1
韩雁飞 《舰载武器(含VCD光盘)》2001,(4):12-16
以舰空导弹使用研究为主线,对与作战使用紧密相关的瞄准和发射问题进行了深入的分析,旨在为舰空导弹作战使用研究提供总体思路和方法,同时也为仿真计算奠定基础。本文内容包括发射装置对目标的跟踪模型,发射参数的计算模型,导弹离轨姿态的确定模型以及射击瞄准的实现模型。 相似文献
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白车身通常有数千焊点,不同的焊点模拟方法对于CAE分析精度有重要影响.白车身CAE开发中焊点模拟有3种主要方式:点对点刚性单元(如RBE2,CROD,CBEAM等)、剪弹性梁单元(如CWELD,CFAST)和ACM2类型的六面体单元加RBE3单元连接.讨论了3种类型焊点模拟方法在工程中的应用,通过模态对比分析和易用性总结得出:点对点刚性使用简单,但分析精度较低;剪弹性梁单元易用性复杂,分析精度最高;ACM2单元易用性和分析精度均介于二者之间.为白车身CAE分析中焊点模拟方式的选择提供参考. 相似文献
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螺旋桨是水下设备推进系统中的核心零件,图谱桨是螺旋桨中的一种,其下又细分为B型、Ka型、AU型、MAU型等。其中,B型图谱桨的桨叶截面形状为翼型,相对其它桨型效率较高。在对经典的图谱和B型图谱桨参数研究比较之后,基于PropCad对B型图谱桨进行了优化设计,导入SolidWorks生成三维模型实现了参数化建模,模型是盘面比为35%的三叶B型图谱桨。通过ICEM CFD对三维模型进行了网格划分,网格分为流动域、旋转域两部分。在Fluent中利用MRF模型进行数值仿真计算,模型设置为RNG k-epsilon模型,将仿真计算的结果与螺旋桨水下实际应用效果进行了对比。仿真结果和实际效果一致,证明了此建模方法的准确性、可靠性,同时也证明了此螺旋桨实际应用时水动力性能优越。 相似文献
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In this paper we present a mixed-integer linear program to represent the decision-making process for heterogeneous fleets selecting vehicles and allocating them on freight delivery routes to minimize total cost of ownership. This formulation is implemented to project alternative powertrain technology adoption and utilization trends for a set of line-haul fleets operating on a regional network. Alternative powertrain technologies include compressed (CNG) and liquefied natural gas (LNG) engines, hybrid electric diesel, battery electric (BE), and hydrogen fuel cell (HFC). Future policies, economic factors, and availability of fueling and charging infrastructure are input assumptions to the proposed modeling framework. Powertrain technology adoption, vehicle utilization, and resulting CO2 emissions predictions for a hypothetical, representative regional highway network are illustrated. A design of experiments (DOE) is used to quantify sensitivity of adoption outcomes to variation in vehicle performance parameters, fuel costs, economic incentives, and fueling and charging infrastructure considerations. Three mixed-adoption scenarios, including BE, HFC, and CNG vehicle market penetration, are identified by the DOE study that demonstrate the potential to reduce cumulative CO2 emissions by more than 25% throughout the period of study. 相似文献
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An experimental and computational investigation was conducted to evaluate the underwater blast response of fully submerged carbon fiber composite plates after prolonged exposure to saline water. The material was a biaxial carbon fiber/epoxy composite with a [±45°] fiber orientation layup. The plates were placed in a saline water bath with a temperature of 65 °C for 35 and 70 days, which simulates approximately 10 and 20 years of operating conditions in accordance to Fick's law of diffusion coupled with Arrhenius's Equation and a reference ocean temperature of 17 °C. Underwater blast experiments were performed in a 2.1 m diameter pressure vessel. The composite plates were placed in the center of the vessel while fully submerged in water, and an RP-85 explosive was detonated at a standoff distance of 102 mm from the center of the plate. Two cases of fluid hydrostatic gage pressures were investigated: 0 MPa, and 3.45 MPa. Two high speed cameras were utilized for three-dimensional Digital Image Correlation, which provided full-field displacements and velocities of the composite plates during underwater blast loading. A third high speed camera captured the behavior of the explosive gas bubble. Moreover, the pressure fields generated by the explosive detonation and resulting gas bubble were recorded with tourmaline pressure transducers. A water diffusion study was completed which showed that the diffusion of water into the composites reached a point of complete saturation after 35 days of exposure. Quasi-static material characterization tests were performed before and after prolonged exposure to saline water. The properties obtained from quasi-static testing also served as material inputs for the numerical models. The quasi-static test results showed that the tensile modulus E1,2 does not change with exposure to saline water, whereas the in-plane shear modulus G12 decreases with saline water exposure. During blast loading, for the case of 0 MPa hydrostatic gage pressure, the gas bubble interacts with the composite plate substantially. In such an event, the out of plane displacement increased for saline water exposed plates when compared to virgin structures. For the case of 3.45 MPa hydrostatic gage pressure, the gas bubble does not visibly interact with the composite plate. In this case, the out of plane displacement for specimens exposed to saline water was similar to the virgin specimen. A fully coupled Eulerian–Lagrangian fluid structure interaction simulation was performed by using the DYSMAS code. The numerical simulations showed that the displacement of fully submerged composite plates is driven by the displacement of fluid, as well as the size of the gas bubble formed by the explosive rather than the peak pressure generated by the explosive. The numerical simulations were in agreement with the experimental findings in terms of pressure history and plate deformation. 相似文献
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Anticipatory signal control in traffic networks adapts the signal timings with the aim of controlling the resulting (equilibrium) flows and route choice patterns in the network. This study investigates a method to support control decisions for successful applications in real traffic systems that operate repeatedly, for instance from day to day, month to month, etc. The route choice response to signal control is usually predicted through models; however this leads to suboptimality because of unavoidable prediction errors between model and reality. This paper proposes an iterative optimizing control method to drive the traffic network towards the real optimal performance by observing modeling errors and correcting for them. Theoretical analysis of this Iterative Optimizing Control with Model Bias Correction (IOCMBC) on matching properties between the modeled optimal solution and the real optimum is presented, and the advantages over conventional iterative schemes are demonstrated. A local convergence analysis is also elaborated to investigate conditions required for a convergent scheme. The main innovation is the calculation of the sensitivity (Jacobian) information of the real route choice behavior with respect to signal control variables. To avoid performing additional perturbations, we introduce a measurement-based implementation method for estimating the operational Jacobian that is associated with the reality. Numerical tests confirm the effectiveness of the proposed IOCMBC method in tackling modeling errors, as well as the influence of the optimization step size on the reality-tracking convergence. 相似文献