共查询到20条相似文献,搜索用时 31 毫秒
1.
2.
3.
A Modeling Language Based on UML for Modeling Simulation Testing System of Avionic Software 总被引:1,自引:1,他引:0
With direct expression of individual application domain patterns and ideas,domain-specific modeling language(DSML) is more and more frequently used to build models instead of using a combination of one or more general constructs.Based on the profile mechanism of unified modeling language(UML) 2.2,a kind of DSML is presented to model simulation testing systems of avionic software(STSAS).To define the syntax,semantics and notions of the DSML,the domain model of the STSAS from which we generalize the domain co... 相似文献
4.
5.
基于时域反射法(TDR)建立了航空导线绝缘故障的数学模型及相应的仿真模型,计算与分析航空导线的绝缘层沿径向发生变化时其特征阻抗及反射系数的变化规律,仿真研究了脉冲波和阶跃波在导线中的传播规律,试验研究了导线特征阻抗的变化以及入射波上升时间对TDR波形的影响。结果表明:随着绝缘损坏量的增加,反射系数的变化率加快;对于相同的绝缘损坏量,绝缘层薄的导线反射系数大,易检测出来;在故障检测中阶跃波优于脉冲波;短路故障容易确定;特征阻抗降低到一定程度时,绝缘故障才能从TDR波形上辨别出来。对于小范围的绝缘故障检测,入射波上升时间越短,TDR波形越能反映故障的特征,但反射脉冲变窄,要求高采样频率;入射波上升时间增长,反射脉冲变宽,幅值降低,但一定程度上有利于检测出绝缘故障。 相似文献
6.
7.
含湍流可变向微下击暴流的建模 总被引:1,自引:0,他引:1
本文建立一个适用于飞行力学研究和飞行员训练的微暴流风切变模型。该模型可模拟以任意方向倾泻的微暴流,其暴核离地高度、暴核直径、暴流强度、暴流倾泻方向、距机场位置等皆为可调参数,使用灵活方便,文中还给出了一种模拟非平衡微暴流湍流的方法,使微暴流模型更趋完善。 相似文献
8.
Airfoil Aeroelastic Flutter Analysis Based on Modified Leishman-Beddoes Model at Low Mach Number 总被引:1,自引:0,他引:1
SHAO Song ZHU Qinghua ZHANG Chenglin NI Xianping Science Technology on Rotorcraft Aeromechanics Laboratory Nanjing University of Aeronautics Astronautics Nanjing China 《中国航空学报》2011,24(5):550-557
Based on modified Leishman-Beddoes (L-B) state space model at low Mach number (lower than 0.3), the airfoil aeroelastic system is presented in this paper. The main modifications for L-B model include a new dynamic stall criterion and revisions of normal force and pitching moment coefficient. The bifurcation diagrams, the limit cycle oscillation (LCO) phase plane plots and the time domain response figures are applied to investigating the stall flutter bifurcation behavior of airfoil aeroelastic systems with symmetry or asymmetry. It is shown that the symmetric periodical oscillation happens after subcritical bifurcation caused by dynamic stall, and the asymmetric periodical oscillation, which is caused by the interaction of dynamic stall and static divergence, only happens in the airfoil aeroelastic system with asymmetry. Validations of the modified L-B model and the airfoil aeroelastic system are presented with the experimental airload data of NACA0012 and OA207 and experimental stall flutter data of NACA0012 respectively. Results demonstrate that the airfoil aeroelastic system presented in this paper is effective and accurate, which can be applied to the investigation of airfoil stall flutter at low Mach number. 相似文献
9.
10.
11.
着陆缓冲装置的性能主要依靠缓冲器来实现,而缓冲器的仿真建模是虚拟样机设计的关键,传统的缓冲器建模方法主要采用理论公式法,其精度较难确定。根据无人机的使用要求,设计一种适用于伞降回收的滑橇缓冲方案;运用缓冲器静压试验及缓冲器落震试验数据曲线建立缓冲器动力学模型;基于缓冲器动力学模型研究全机多刚体落震模型,对无人机着陆缓冲过程的动态特性进行仿真分析;应用有限元技术对滑橇结构动态响应进行非线性动力学仿真分析,并根据仿真结果优化滑橇缓冲装置设计参数。结果表明:仿真结果与全机落震试验结果相吻合;所建立的无人机落震模型精度较高,满足工程需要,能极大地减少试验成本,缩短研制周期。 相似文献
12.
基于Mori-Tanaka有限元法的粘弹复合推进剂非线性界面脱粘 总被引:2,自引:2,他引:0
为了研究复合推进剂基体的大应变粘弹性和界面的非线性脱粘,将Mori-Tanaka法和有限元数值求解相结合,提出了一种Mori-Tanaka有限元法。同时,为验证该方法的有效性,针对推进剂夹杂随机填充的特点,提出了一种含非线性界面脱粘的数值仿真法。最后以某推进剂配方为算例,对两种方法的计算结果了进行比较。结果表明,两种方法结果接近,从而验证了Mori-Tanaka有限元法的有效性,且该方法计算量小,极大的提高了计算效率。两种方法的提出,可以有效的用来分析界面对推进剂力学性能的影响。 相似文献
13.
从贯彻GJB9001A-2001有关生产和检验共用设备控制的特殊要求谈起,对于如何理解该标准相关条款的内容并有的放矢地做好共用设备的测量控制工作阐述了作者的一些观点。同时还就具体实施共用设备检验前校准时应注意的问题提出了意见。 相似文献
14.
《中国航空学报》2021,34(1):380-396
A theoretical formulation for time-domain nonlinear aeroelastic analysis of a flexible wing model is presented and validated by wind tunnel tests. A strain-based beam model for nonlinear structural analysis is combined with the Unsteady Vortex Lattice Method (UVLM) to form the complete framework for aeroelastic analysis. The nonlinear second-order differential equations are solved by an implicit time integration scheme that incorporates a Newton-Raphson sub-iteration technique. An advanced fiber optic sensing technique is firstly used in a wind tunnel for measuring large structural deformations. In the theoretical study, the nonlinear flutter boundary is determined by analyzing the transient response about the nonlinear static equilibrium with a series of flow velocities. The gust responses of the wing model at various gust frequencies are also studied. Comparisons of the theoretical and experimental results show that the proposed method is suitable for determining the nonlinear flutter boundary and simulating the gust response of flexible wings in the time domain. 相似文献
15.
研究了分数阶傅里叶变换(Fractional Fourier Transform,FRFT)抗线性调频(Linear Frequency Modulation,LFM)干扰技术,提出了一种基于FRFT域幅度一阶矩的逐精度求取最佳变换阶次的方法,并针对连续LFM干扰提出了一种求取最佳变换阶次的策略。同时针对全球导航卫星系统(Global Navigation Satellite System,GNSS)中的LFM干扰,对信号的预处理、阈值的自适应选取做了研究与分析,给出了相应的处理方法。仿真结果表明,该方法能够减少抗连续LFM干扰时求取最佳变换阶次的计算量,而且可以有效抑制GNSS接收机中的LFM干扰。 相似文献
16.
针对圆台共形阵列,建立了空时二维自适应处理(STAP)的杂波模型,给出了圆台阵列杂波抑制最优权值的计算方法。在此基础之上,为了实现可应用到实际环境中的自适应处理方法,进一步讨论了将局部联合域(JDL)降维算法推广至圆台阵列中的问题。得出了圆台阵列JDL算法降维变换矩阵的表达形式,研究了参考波束的数目选取、波束指向等因素对降维损失的影响。理论分析以及仿真结果表明,通过合理选择通道数、波束方位向指向间隔等参数,该算法能够减少自适应波束形成的计算量,而且可以用较少的训练样本获得较好的处理性能。 相似文献
17.
18.
19.
《Aerospace Science and Technology》2005,9(3):223-232
The real-time pseudo-dynamic sub-structure (SubPSD) test is a new procedure for dynamic testing of structures. Here, the actual test specimen is a part, i.e. sub-structure, of a larger, complex system. The main structure is simulated on a computer which is in interaction with the test rig.One possible application is the qualification test of a payload (sub-structure) mounted in a carrier rocket (computer model). Consideration of the interaction between main- and sub-structure will yield more realistic results than conventional shaking table tests. This can be a good basis for a more effective, light-weight design of the payload.An algorithm is presented, which is based on the Newmark time domain solution of the equation of motion. It uses sub-stepping instead of iteration to reach equilibrium within each time step. This algorithm and a suitable hardware allow for true real-time performance of the SubPSD test, even with oscillatory sub-structures. Numerical studies are presented which demonstrate the accuracy but also the limits of the procedure. Experimental results of a 4 d.o.f. test model are compared to the numerical results. 相似文献
20.
应变控制下NEPE推进剂非线性疲劳损伤 总被引:2,自引:1,他引:1
为研究高能硝酸酯增塑聚醚(NEPE)推进剂的非线性疲劳损伤特性,基于损伤力学和黏弹性理论,建立了一种非线性疲劳损伤模型.该模型考虑了材料疲劳过程中刚度衰减的特征.建立的疲劳损伤模型,通过动态热机械分析仪(DMA)进行5组不同应变水平下的疲劳实验,获得模型参数,并对模型进行验证,利用电荷耦合器件图像传感器(CCD)进行显微观察,分析了应变加载历史对NEPE推进剂微观上的影响.结果表明:提出的损伤演化模型能够很好地描述NEPE推进剂应变控制下的非线性疲劳损伤;定应变往复拉伸造成了推进剂颗粒与基体的脱湿,在循环初期脱湿速度较快,随着循环周期增加,脱湿程度逐渐趋于稳定. 相似文献