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991.
YANG Xiao-dong 《应用数学和力学(英文版)》2005,26(8):989-995
IntroductionThe class of systems with axially moving materials involves power transmission chains,band saw blades and paper sheets during processing. Vibration of such systems is generallyundesirable. The traveling tensioned Euler-Bernoulli beam is the pr… 相似文献
992.
An analysis is presented for the primary resonance of a clamped-hinged beam, which occurs when the frequency of excitation is near one of the natural frequencies,n . Three mode interaction (2 31 and 3 1 + 22) is considered and its influence on the response is studied. The case of two mode interaction (2 31) is also considered to compare it with the case of three mode interaction. The straight beam experiencing mid-plane stretching is governed by a nonlinear partial differential equation. By using Galerkin's method the governing equation is reduced to a system of nonautonomous ordinary differential equations. The method of multiple scales is applied to solve the system. Steady-state responses and their stability are examined. Results of numerical investigations show that there exists no significant difference between both modal interactions' influences on the responses. 相似文献
993.
994.
In this paper we prove Phragmén-Lindelöf type alternative for the initial boundary problem of Stokes equation, i. e. we show that the energy expression for the solution of the initial boundary problem must either grow exponentially or decay exponentially with axial distance from the end of a semi-infinite strip. For the case of decay, we also establish the pointwise estimate for the maximum module of the Stokes flow and present a method for obtaining explicit bounds for the total energy.Project supported by the National Natural Science Foundation of China and Zhongshan University Science Foundation 相似文献
995.
T. Yano 《Shock Waves》1996,6(6):313-322
A weakly nonlinear plane acoustic wave is emitted into an ideal gas of semi-infinite extent from an infinite plate by its
sinusoidal motion of single period. The wave develops into anN wave in the far field, as long as the energy dissipation is negligible everywhere except for discontinuous shock fronts.
The third-order effects at shock fronts are evaluated, i.e., the generation of reflected acoustic wave as a result of the
interaction of shock and expansion wave and the production of entropy by the energy dissipation at shock fronts. Consideration
of these effects enables one to estimate the whole mass, momentum and total excess energy (sum of the kinetic energy and excess
of internal energy over an initial undisturbed value) transported by theN wave to the accuracy of third order of wave amplitude. It is shown that the mass and total excess energy transported by theN wave increase and the momentum decreases to asymptotic limits as the wave propagates. The result shows good agreement with
a numerical result obtained by solving the Euler equations with a high-resolution TVD upwind scheme. 相似文献
996.
本文利用非线性时空有限方法和样条有限元技术对具有初内力的板的非线性频响特性进行了分析,计算了在不同初始内力下方板的大振幅自由振动、有阻尼强迫振动和矩形板的内共振。 相似文献
997.
In this paper, the higher-order asymptotic solution to the Cauchy problem of a nonlinear wave equation is found by using a
computer algebra-perturbation method. The secular terms in the solution from straightforward expansions are eliminated with
the straining of characteristic, coordinates and the use of the renormalization technique, and the four-term uniformly valid
solution is obtained with the symbolic computation by using a computer algebra system. The comparison of the derived asymptotic
solution and the numerical solution shows that they coincide with each other for smaller ε and agree quite well for larger
ε (e. g., ε=0.25)
Project supported by the National Natural Science Foundation of China and Shanghai Municiple Natural Science Foundation 相似文献
998.
999.
Jeremiah Rushchitsky 《Comptes Rendus Mecanique》2002,330(3):175-180
The problem of self-switching plane waves in elastic nonlinearly deformed materials is formulated. Reduced and evolution equations, which describe the interaction of two waves the power pumping wave and the faint signal wave are obtained. For the case of wave numbers matching the pumping and signal waves, a procedure of finding the exact solution of evolution equations is described. The solution is expressed by elliptic Jacobi functions. The existence of the power wave self-switching is shown and commented. To cite this article: J. Rushchitsky, C. R. Mecanique 330 (2002) 175–180. 相似文献
1000.
LIF技术测量浓度场的影响因素分析 总被引:5,自引:0,他引:5
本文研究了作为示踪剂的荧光素钠的谱图,测定了荧光素钠在蒸馏水和普通自来水中的吸光系数,估算了荧光分子的平均寿命。最后,详细分析了浓度、激光功率、温度、pH值和截止滤光片对荧光强度的影响。 相似文献