scholarly journals Wave Mode Control of Cantilever Slab Structure of T-Beam Bridge with Large Aspect Ratio

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Tingting Liu ◽  
Chuanping Zhou ◽  
Zhigang Yan ◽  
Guojin Chen
Keyword(s):  
Aspect Ratio ◽  
Elastic Wave ◽  
Wave Mode ◽  
Control Force ◽  
Cantilever Plate ◽  
Large Aspect Ratio ◽  
Plate Structure ◽  
Beam Bridge ◽  
T Beam ◽  
Wave Control

The cantilever plate structure in a T-beam bridge with a large aspect ratio will cause vibration under the influence of environmental disturbance and self-stress, resulting in fatigue damage of the plate structure. Wave control based on elastic wave theory is an effective method to suppress the vibration of the cantilever plate structure in a beam bridge. Based on the classical thin plate theory and the wave control method, the active vibration control of the T-shaped cantilever plate with a large aspect ratio in the beam bridge is studied in this paper. The wave mode control strategy of structural vibration is analyzed and studied, the controller is designed, the vibration mode function of the cantilever plate is established, and the control force/sensor feedback wave control is implemented for the structure. The dynamic response of the cantilever plate before and after applying wave control force is analyzed through numerical examples. The results show that the response of the structure is intense before control, but after wave control, the structure increases damping, absorbs the energy carried by the elastic wave in the structure, weakens the sharp response, and changes the natural frequency of the structure to a certain extent.

Hybrid Active Wave/Mode Control of Space Prestressed Taut Cable Net Structures

2018 ◽  
Vol 10 (06) ◽  
pp. 1850062 ◽  
Author(s):  
Xiao-Fei Ma ◽  
Tuan-Jie Li ◽  
Zuo-Wei Wang
Keyword(s):  
Shape Control ◽  
Large Scale ◽  
Control Method ◽  
Wave Mode ◽  
Control Model ◽  
Force Balance ◽  
Control Force ◽  
Mode Control ◽  
Active Wave ◽  
Wave Control

The space environments and special mission demands require large-scale and high shape accuracy cable net structures. The vibration control is an essential issue for shape control and performance conservation of large flexible cable net structures. This paper investigates the hybrid active wave/mode control of space prestressed taut cable net structures. First, the traveling wave dynamic model of cable net structures is explored by elemental waveguide and propagation equations of cables together with force balance conditions and compatibility conditions of joints. Then, the active wave control model is established by using the assumption forms of wave controllers to adjust the mechanical boundaries of the controlled joints. Finally, the hybrid active wave/mode control model is proposed by constructing the mapping relationship between wave control force, modal damping and natural frequencies. The proposed control method is verified by a planar cable net structure and the results show that the hybrid active wave/mode control can give a better broadband vibration attenuation performance for space prestressed taut cable net structures.

Machine-learning based design of digital materials for elastic wave control

2021 ◽  
pp. 101372
Author(s):  
Jingyi Zhang ◽  
Yiwen Li ◽  
Tianyu Zhao ◽  
Quan Zhang ◽  
Lei Zuo ◽  
...  
Keyword(s):  
Machine Learning ◽  
Elastic Wave ◽  
Wave Control

Numerical Modeling of Fluid-Induced Rotordynamic Forces in Seals With Large Aspect Ratio

2012 ◽  
Author(s):  
Alexandrina Untaroiu ◽  
Costin D. Untaroiu ◽  
Houston G. Wood ◽  
Paul E. Allaire
Keyword(s):  
Finite Difference ◽  
Aspect Ratio ◽  
Finite Difference Method ◽  
Difference Method ◽  
Dynamic Properties ◽  
Bulk Flow ◽  
Large Aspect Ratio ◽  
Flow Method ◽  
Dynamic Coefficients ◽  
Aspect Ratios

Traditional annular seal models are based on bulk flow theory. While these methods are computationally efficient and can predict dynamic properties fairly well for short seals, they lack accuracy in cases of seals with complex geometry or with large aspect ratios (above 1.0). In this paper, the linearized rotordynamic coefficients for a seal with large aspect ratio are calculated by means of a three dimensional CFD analysis performed to predict the fluid-induced forces acting on the rotor. For comparison, the dynamic coefficients were also calculated using two other codes: one developed on the bulk flow method and one based on finite difference method. These two sets of dynamic coefficients were compared with those obtained from CFD. Results show a reasonable correlation for the direct stiffness estimates, with largest value predicted by CFD. In terms of cross-coupled stiffness, which is known to be directly related to cross-coupled forces that contribute to rotor instability, the CFD predicts also the highest value; however a much larger discrepancy can be observed for this term (73% higher than value predicted by finite difference method and 79% higher than bulk flow code prediction). Similar large differences in predictions one can see in the estimates for damping and direct mass coefficients, where highest values are predicted by the bulk flow method. These large variations in damping and mass coefficients, and most importantly the large difference in the cross-coupled stiffness predictions, may be attributed to the large difference in seal geometry (i.e. the large aspect ratio AR>1.0 of this seal model vs. the short seal configuration the bulk flow code is usually calibrated for, using an empirical friction factor).

scholarly journals Mesoscale flows in large aspect ratio simulations of turbulent compressible convection

2005 ◽  
Vol 430 (3) ◽  
pp. L57-L60 ◽  
Author(s):  
F. Rincon ◽  
F. Lignières ◽  
M. Rieutord
Keyword(s):  
Aspect Ratio ◽  
Large Aspect Ratio
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