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991.
992.
Summary The article presents a fast numerical algorithm for calculating the response of a halfspace under any surface loads. Under
certain conditions there exists an analytical solution to the problem in the Fourier domain. To get the desired response,
a numerical inverse Fourier transform of this analytic solution has to be made. By using a wavelet decomposition, the proposed
algorithm can reduce the calculation time significantly, thus allowing the computation of complex problems. As an example,
the response of the beam-halfspace coupled system under moving load is presented.
Received 6 March 1997; accepted for publication 20 May 1997 相似文献
993.
APPLICATION OF WAVELET TRANSFORM TO BIFURCATION AND CHAOS STUDY 总被引:2,自引:0,他引:2
I.IntroductionThetypesofmotionforanonlinearvibrationsystemmaybeperiodic,quasiperiodicorchaotic.Foragivensetofparametersofthesystem,Poincarkmap,powerspectral,waveformandLyapunovexponentareusuallyutilizedtoseewhethertheresponseofthesystemischaoticornot,butitisdiftlculttodeterminepreciselytheexistingdomainsorattractingbasinsofdifferenttypesofmotionsinparametricspaceorinitialvaluespaceonlyfromgraphicsstudy,andcomputingLyapunovexponentistimeconsuming.Aswavelettransformcanreveallocalpropertyinboth… 相似文献
994.
Marius Buliga 《Journal of Elasticity》1998,52(3):201-238
995.
Singularly perturbed systems with structural perturbations are analyzed for stability. New sufficient conditions of asymptotic stability and uniform asymptotic stability are established. The systems in question are widely used in control theory, engineering, etc 相似文献
996.
小波分析技术在陀螺故障诊断中的应用研究 总被引:4,自引:0,他引:4
小波分析是一种全新的时一频两维分析技术,其对高频突变信号和低频缓变信号的分析有其独特的优点。本文分析了小波分析技术的原理,提出了将其引入机械设备故障诊断中的方法。通过对有故障陀螺振动信号的多尺度分析,研究故障信号小波变换轴心轨迹分量图,建立典型故障特征模型,从而对单故障及多故障问题进行分析与诊断。 相似文献
997.
Fan Xijun 《Acta Mechanica Sinica》1992,8(4):295-306
The constitutive equation for a semiconcentrated fibre suspension in the Oldroyd-B fluid has been derived from a statistical
model of such a suspension by employing the molecular theory for polymeric liquids. To circumvent theoretical difficulties
in viscoelastic fluid mechanics, several simplified models are used to account for the interactions of fibres and polymer
molecules. Some of material functions are calculated in terms of the constitutive equation.
The project Supported by the University of Melbourne of Australia, the National Natural Science Foundation of China and Zhejiang
Province 相似文献
998.
Alex Elías-Züñiga 《Nonlinear dynamics》2007,49(1-2):307-315
The aim of this paper is to show how Jacobi elliptic functions in combination with the averaging and the harmonic balance
methods can be applied to obtain the approximate solution of two coupled, ordinary differential equations having a spring
with cubic nonlinearity and subjected to driving forces of elliptic type. By an appropriate choice of the system parameter
values, it is possible to show that our derived solution represents the exact steady-state solution of the undamped Duffing
equation with driving force of elliptic type. At the end of this work, we also demonstrate the validity of our derived solution
by comparing the amplitude–time response curves with those of the numerical integration solutions. 相似文献
999.
Hot wire signals obtained in grid-turbulence are processed through orthogonal wavelet transform. It is shown that using wavelet
decomposition in combination with the form of scaling named Extended Self Similarity, some statistical properties of fully
developed turbulence can be extended to very low Reλ flows. Furthermore, based on the wavelet decomposition, a new technique for coherent structures identification is introduced.
We present results obtained in grid turbulence data at low and very low Reλ conditions. 相似文献
1000.
K. S. Matviichuk 《International Applied Mechanics》2006,42(6):699-713
Sufficient conditions for the technical stability in measure of a nonstationary control system with variable structure are
established. The controller of the system has feedback-switched filters functioning together with shaper and actuator. It
is assumed that the nonstationary parameters of the system vary within given ranges, at a finite rate, with appropriate control
laws, with adjustment against mismatch signal, its derivatives of finite order, and all variable parameters of the filter.
The parameters of the switching hyperplane remain constant. This approach for analysis of technical stability does not involve
sliding mode conditions. Criteria of technical instability in measure for the control system under consideration are formulated
using the properties of systems of comparison from below. The general criteria of technical stability and instability are
applied to nonstationary filtered-control systems of variable structure of the third order. The comparison method based on
normalized Lyapunov functions is used
__________
Translated from Prikladnaya Mekhanika, Vol. 42, No. 6, pp. 110–127, June 2006. 相似文献