Centrifuge simulations of wave propagation using a moving load system

Author(s):  
K. Itoh ◽  
A. Takahashi ◽  
O. Kusakabe ◽  
M. Koda ◽  
O. Murata ◽  
...  
Keyword(s):  
Author(s):  
Bo Zhao ◽  
David A. Peters

Abstract The space-time finite element method has emerged as a promising alternative numerical analysis technique for structural dynamics. This paper concentrates on hp-version triangular elements based on a variational statement of elasto-dynamics formed on Hamilton’s law of varying action. As such, forces and momenta are weak; and element boundaries may cut across space and time. This forms a natural framework for problems with both moving load and wave propagation. This paper presents applications of the method to such problems with numerical results and conclusions regarding proper mesh geometry.


2022 ◽  
pp. 136943322110632
Author(s):  
Jianyi Ji ◽  
Ronghui Wang ◽  
Niujing Ma ◽  
Kunhong Huang ◽  
Xiang Zhang

A physical perspective of the propagation and attenuation of flexural waves is presented in this paper for the dynamic behaviors of cable stayed beams subjected to a moving load. Based on the method of reverberation-ray matrix (MRRM), the waveform solutions of the wave equations of a simplified beam-cable system subjected to a moving load (hereinafter referred to as a beam-cable system) are given, and the theory is verified by a numerical example. The dynamic response of cable stayed beams is decomposed into nine kinds of flexural waves, including traveling waves, near-field waves, and nondispersive waves, according to the wavenumber characteristics. Numerical examples are analyzed to demonstrate the propagation characteristics of flexural waves through cable stayed beams. Numerical results show that the flexural waves in the cable stayed beams are mainly low-frequency waves whose frequencies are less than 3 times the structural fundamental frequency, which can be used to further improve the computational efficiency of response analysis method based on MRRM, and the proportion of high-frequency components increases gradually with increasing structural stiffness. The near-field wave can be transformed into a traveling shear wave when its frequency is larger than the critical frequency, which decreases with increasing radius of gyration and decreasing elastic modulus of the beam. With the increase in the radius of gyration and the elastic modulus of the beam, the attenuation effect of the near-field wave weakens. The wave velocity and the wave dispersion effect have a positive correlation with the stiffness-related parameters of the beam-cable system. The study of the effect of the beam-cable system parameters on flexural wave propagation characteristics can be applied to achieve a better dynamic design for engineering structures.


1981 ◽  
Vol 48 (3) ◽  
pp. 613-618 ◽  
Author(s):  
L. Jezequel

The motion of a beam or a plate resting on an elastic foundation and subjected to a moving load has been studied by numerous authors. But the extension of these studies to the case of periodic structures is difficult. In this paper, a method allowing the calculation at low numerical cost of periodically supported beams subjected to a moving force, is proposed. The interpretation of this method on the basis of the free-wave propagation equations in periodic structures has led to the definition of the predominant, so-called “primary,” critical speeds. Individual examples were used to test the method. It was also possible to define the limits of a Winkler continuous model in representing the support reactions.


Author(s):  
J. M. Galbraith ◽  
L. E. Murr ◽  
A. L. Stevens

Uniaxial compression tests and hydrostatic tests at pressures up to 27 kbars have been performed to determine operating slip systems in single crystal and polycrystal1ine beryllium. A recent study has been made of wave propagation in single crystal beryllium by shock loading to selectively activate various slip systems, and this has been followed by a study of wave propagation and spallation in textured, polycrystal1ine beryllium. An alteration in the X-ray diffraction pattern has been noted after shock loading, but this alteration has not yet been correlated with any structural change occurring during shock loading of polycrystal1ine beryllium.This study is being conducted in an effort to characterize the effects of shock loading on textured, polycrystal1ine beryllium. Samples were fabricated from a billet of Kawecki-Berylco hot pressed HP-10 beryllium.


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