共查询到20条相似文献,搜索用时 265 毫秒
1.
建立了非线性随机动力模型—带噪声的能源Logistic反馈控制模型,应用随机平均法对随机动力模型进行了简化,得到了一个二维的扩散过程.二维过程满足Ito型随机微分方程,应用不变测度理论研究了该模型的随机分岔.最后,给出了数值实验验证了相应的结论. 相似文献
2.
单自由度摩擦系统离散模型 总被引:2,自引:0,他引:2
发展了两种随机离散数学模型:导出了一个以二维平均映射描述的随机模型,并建立了一个概率预报模型.通过实例对不同模型进行了比较,对于平均映射模型,分岔图指出了外噪声对系统性质的影响,通过符号动力学方法分析指出概率预报模型的随机性质. 相似文献
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《数学的实践与认识》2015,(9)
考虑了一个新三维指数系统的Hopf分岔,并且分析了指数系统添加非线性控制器后的Hopf分岔.通过严格的数学推导给出受控系统发生余维一,余维二和余维三的Hopf分岔的参数条件,证明了可以控制系统在指定区域内发生退化分岔和可调控分岔的稳定性,并且通过数值模拟验证了得出的结论. 相似文献
4.
交通流模型的分岔点对应临界的交通状态,对研究交通流的稳定性具有重要的理论意义.为了分析宏观交通流模型的分岔特征,通过对低维宏观交通流模型的求解得到两个平衡点,并讨论了其稳定性,发现该模型存在一个跨临界分岔点.数值仿真验证了结论的正确性,并且在一定条件下,通过改变响应时间会影响到最终的平衡状态. 相似文献
5.
《应用数学和力学》2020,(7)
基于Fourier变换方法,对移动荷载作用下三维、二维和一维轨道-地基模型的振动响应特征进行了研究,将轨道视为Timoshenko梁,比较了不同速度和地基厚度下各计算模型之间的响应差异.研究结果表明:三维模型存在一个地基等效刚度,为波数和频率的函数.二维和三维模型的临界速度较为接近,但比一维地基梁模型要小得多.荷载速度小于地基临界速度时,三维模型的梁挠度幅值最小,二维模型次之,一维模型梁挠度最大.当荷载速度达到或超过临界速度时,二维模型的梁挠度幅值变得最大,此时三者的挠度时程曲线存在明显差别.二维和三维模型的地层水平位移幅值先随地基深度增加而增大,在某一深度达到最大值后随深度增加逐渐减小,竖向位移幅值则随深度的增加逐渐减小. 相似文献
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张康明 《数学的实践与认识》2010,40(14)
讨论了一个具有唯一鞍焦点的多参数三维混沌系统,该系统包含了Sprott提出的一个最简混沌模型.在特定的条件下得到了Hopf分岔的存在性条件;进一步利用规范型理论获得了决定Hopf分岔方向和分支周期解稳定性的公式,同时利用计算机模拟证实本文的理论分析结果. 相似文献
10.
《数学年刊A辑》2001,22(2):263-264
Koiter型的二维非线性壳模型合理性的验证
P.G.Ciarlet A.Roquefort
第一作者最近提出了“Koiter型”的二维非线性壳模型,该文证明了根据加在可容许的不可延拓位移所成的伴随流形上的两组互斥的假定,这个二维模型的解的形式渐近展开式中的主项,以厚度为“小”参数,或者满足一个非线性弹性“薄膜”壳的二维方程,或者满足一个非线性弹性“弯曲”壳的二维方程.
这些结论与最近由B.Miara,接着由V.Lods和B.Miara对于三维非线性弹性方程解的形式渐近展开式的主项,也是以厚度为“小”参数,所得出的结论相同.于是,这里所考虑的Koiter型的非线性壳模型合理性得到验证,至少在形式上得到验证. 相似文献
11.
The purpose of this paper is to put forward a new model of conflict analysis - the 3-D graph model and its stability analysis, including the three most important factors of conflict analysis. The rules concerning the movement of multiple players are still considered based on practical restrictions. Therefore the 3-D graph model may be used to solve real problems effectivity. 相似文献
12.
This paper deals with the problem of switching design for guaranteed cost control of discrete-time two-dimensional (2-D) nonlinear switched systems described by the Roesser model. The switching signal, which determines the active mode of the system, is subject to a state-dependent process whose values belong to a finite index set. By using 2-D common Lyapunov function approach, a sufficient condition expressed in terms of tractable matrix inequalities is first established to design a min-projection switching rule that makes the 2-D switched system asymptotically stable. The obtained result on stability analysis is then utilized to synthesize a suboptimal state feedback controller that minimizes the upper bound of a given infinite-horizon cost function. Finally, two numerical examples are given to illustrate the effectiveness of the proposed design method. 相似文献
13.
A theoretical model for Reynolds-stress and dissipation-rate budgets in near-wall region 总被引:6,自引:0,他引:6
A 3-D wave model for the turbulent coherent structures in near-wall region is proposed. The transport nature of the Reynolds
stresses and dissipation rate of the turbulence kinetic energy are shown via computation based on the theoretical model. The
mean velocity profile is also computed by using the same theoretical model. The theoretical results are in good agreement
with those found from DNS, indicating that the theoretical model proposed can correctly describe the physical mechanism of
turbulence in near wall region and it thus possibly opens a new way for turbulence modeling in this region. 相似文献
14.
2—D奇异系统正则观测器的设计 总被引:3,自引:0,他引:3
本文讨论了一类2-D奇异系统正则观测器的设计问题。为此,首先将2-D奇异系统等价为降阶正则系统和一纯代数等式的组合,在此基础上,从理论上解决了2-D奇异系统的一类正则观测器的设计问题。 相似文献
15.
Yuncheng You 《Mathematical Methods in the Applied Sciences》2012,35(4):398-416
In this work, the existence and properties of a global attractor for the solution semiflow of the Oregonator system are proved. The Oregonator system is the mathematical model of the celebrated Belousov–Zhabotinskii reaction. A rescaling and grouping estimation method is developed to show the absorbing property and the asymptotic compactness of the solution trajectories of this three‐component reaction–diffusion system with quadratic nonlinearity. It is also proved that the fractal dimension of the global attractor is finite and an exponential attractor exists for the Oregonator semiflow. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
16.
3-D network model and its parameter calibration 总被引:2,自引:0,他引:2
A material model, whose framework is parallel spring-bundles oriented in 3-D space, is proposed. Based on a discussion of
the discrete schemes and optimum discretization of the solid angles, a 3-D network cell consisted of one-dimensional components
is developed with its geometrical and physical parameters calibrated. It is proved that the 3-D network model is able to exactly
simulate materials with arbitrary Poisson ratio from 0 to 1/2, breaking through the limit that the previous models in the
literature are only suitable for materials with Poisson ratio from 0 to 1/3. A simplified model is also proposed to realize
high computation accuracy within low computation cost. Examples demonstrate that the 3-D network model has particular superiority
in the simulation of short-fiber reinforced composites. 相似文献
17.
This article explicates the development of top-view numeric coding of 3-D cube structures within a design research project focused on 3-D visualization skills for elementary grades children. It describes children's conceptual development of 3-D cube structures using concrete models, conventional 2-D pictures and abstract top-view numeric representations integrated with the Geocadabra Construction Box, a computer interface that simulates these representations dynamically. 相似文献
18.
本文针对文献[1]所述复合材料层合板三维模型,在三维线性弹性理论基本方程和经典变分原理的基础上,通过分块矩阵运算和线性Lagrange乘子法,推导出比文献[1]更全面更系统的基本方程和变分原理,使复合材料层合板三维线性理论臻于完整。 相似文献
19.
The Oregonator model is the mathematical dynamics which describes the Field-Körös-Noyes mechanics of the famous Belousov-Zhabotinskii? reaction. In this work, we establish some fundamental analytic properties of this dynamics and its corresponding steady state. Under various conditions on the parameters and the size of the reactor, we examine the existence and non-existence of non-constant steady states. In particular, for some properly chosen parameter ranges, we prove the occurrence of the Turing pattern generated by this Oregonator model. Our results exhibit interesting and very different roles of the diffusion rates and the reactor in the formation of the Turing pattern. Our mathematical analysis mainly relies on a priori estimates and the topological degree argument. 相似文献
20.
求解二维波动方程正演反演问题的半离散方法 总被引:1,自引:0,他引:1
本文用半离散方法将二维波动方程离散为一维耦合波动方程组.给出了离散的收敛性及波动方程组的适定性.利用这种方法可以求解波动方程系数及演问题. 相似文献