Independent Modal Control of Beams With Spatially Distributed Orthogonal Photostrictive Actuators

2012 ◽  
Author(s):  
Jing Jiang ◽  
Hong-Hao Yue ◽  
Wen-Xiu Cheng ◽  
Zong-Quan Deng ◽  
Horn-Sen Tzou
Keyword(s):  
Light Intensity ◽  
Time History ◽  
High Energy ◽  
Modal Control ◽  
Simply Supported Beam ◽  
Simply Supported ◽  
Electrode Shape ◽  
Intensity Control ◽  
Spatially Distributed ◽  
Photostrictive Actuators

High-energy light regulated photostrictive actuators provide a new wireless and non-contact precision actuation mechanism. For PLZT actuators with 0–3 polarization, the electrode shape can be designed to achieve desired modal control effects. In this paper, the photonic control of flexible shells using shaped photostrictive actuators is investigated. Spatially distributed and shaped 0–3 polarized PLZT actuators are selected to achieve independent control of various natural modes of a simply supported beam. Constitutive equations which define the time history response of photo-induced strain for 0–3 polarized PLZT actuator are presented. Based on experimental observation and theoretical analysis, the relationships of saturated photovoltage and time constant with actuator thickness and light intensity are formulated. Based on the orthogonality of the mode shape function, distributed orthogonal modal actuators designed for a simply supported beam are proposed. In order to realize the actuator shape design, paired spatially shaped photostrictive actuators are segmented and respectively placed on the top and bottom surfaces of the beam and the light direction of each segment actuator is regulated. Their control effectiveness with constant light intensity control is evaluated and the time history analysis is presented.

Flexoelectric Vibration Control of Plates by Line Electrodes

2016 ◽  
Author(s):  
X. F. Zhang ◽  
H. Y. Li ◽  
H. S. Tzou
Keyword(s):  
Electric Field ◽  
Vibration Control ◽  
Bottom Surface ◽  
Modal Control ◽  
Sensors And Actuators ◽  
Structural Dynamic ◽  
Simply Supported Beam ◽  
Simply Supported ◽  
Flexoelectric Effect ◽  
Conductive Line

The electric polarization induced by the strain gradient is the direct flexoelectric effect; the mechanical stress/strain induced by the electric field gradient is the converse flexoelectric effect. Accordingly, flexoelectric sensors and actuators are respectively designed to monitor the structural dynamic behavior and to control the structural vibration. In this study, a line-electrode induced flexoelectric actuation is designed to control the plate vibrations. A flexoelectric layer laminated on the thin plate is used as a distributed actuator. The bottom surface of the flexoelectric actuator is a common electrode and the top surface is driven by a conductive line to generate an inhomogeneous electric field. Based on the converse flexoelectric effect, the electric filed gradient induces mechanical stresses in the flexoelectric layer resulting in induced bending moments to the plate structure. With the control moment imposed on the plate, flexoelectric vibration control of the plate is evaluated in this study. The objective of this study is to explore the modal control effects of the plate by the conductive line excitation. For a plate with two opposite sides simply supported and the other two are free (SS-F-SS-F), vibration control response of the plate is studied when the conductive line locates parallel to the y width direction. Then, independent modal control effects (i.e., the induced or controllable displacements by the flexoelectric actuator) are evaluated for the modes (1,1), (1,2), (1,3), (2,1) and (3,1) with different line actuation locations. Control effects of the conductive line location to various plate modes are explored and results show that the optimal conductive line location differs for different plate modes. When the FF width decreases to far less than the SS length, the SS-F-SS-F plate is degraded to a simply supported beam. Then, control effects for modes (1,1), (2,1) and (3,1) with different conductive line locations are discussed. The results are compared with the control effect derived directly by the simply supported beam theory. Thus, this study suggests that plate vibration can be controlled by the line-electrode induced converse flexoelectric effect. Conductive line locations are critical to control of various plate modes.

The Application of E Shaped Steel Bearing on the Simply Supported Beam Bridge

2011 ◽  
Vol 90-93 ◽  
pp. 3141-3144
Author(s):  
Ling Jun Kong ◽  
Yan Bei Chen ◽  
Jun Liu ◽  
Qi Bin Jiang
Keyword(s):  
Computational Models ◽  
Time History ◽  
Earthquake Response ◽  
Bending Moments ◽  
Shear Forces ◽  
Simply Supported Beam ◽  
Simply Supported ◽  
Related Data ◽  
Nonlinear Time History ◽  
Beam Bridge

To study the application of E shaped steel bearing on the simply supported beam bridge, the Xinhua bridge is analyzed by the nonlinear time-history method and the Midas/Civil software, considering the interaction between pile and soil. The related data are obtained through two computational models. And the data are compared in this paper. The results show that the bending moments and shear forces of the bottom of the fixed pier are reduced, due to using the E shaped steel bearing at the fixed pier. The E shaped steel bearing dissipates the earthquake energy and reduces the earthquake response of the bridge.

Pedestrian-Induced Vibration of a Simply-Supported Beam

2016 ◽  
Vol 33 (5) ◽  
pp. 577-591 ◽  
Author(s):  
S.-H. Yin
Keyword(s):  
Analytical Approach ◽  
Time History ◽  
Step Length ◽  
Vertical Vibration ◽  
Contact Duration ◽  
Natural Period ◽  
Simply Supported Beam ◽  
Simply Supported ◽  
History Of ◽  
Analytical Relations

AbstractThis paper presents an analytical approach to analyze the vertical vibration of a simply supported beam subjected to pedestrian-induced loads. The loading time history of an individual footstep is simplified as a rectangular force pulse, and each identical footstep load acts at different locations along the beam depending on a step length. Although the loading model is very simple, it enables us to find analytical relations between the pacing parameters and the beam response. The results showed that the dependence of the pacing period, footstep contact duration, time delay of traveling between two pedestrians on the natural period of the beam as well as the step length can influence the dynamic response of the beam significantly.

scholarly journals Effect of Material Characteristics of High Damping Rubber Bearings on Aseismic Behaviors of a Two-Span Simply Supported Beam Bridge

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Yumin Zhang ◽  
Jiawu Li
Keyword(s):  
Time History ◽  
Bending Moment ◽  
Seismic Energy ◽  
Northridge Earthquake ◽  
Horizontal Shear ◽  
Simply Supported Beam ◽  
Simply Supported ◽  
High Damping Rubber ◽  
Rubber Bearings ◽  
Beam Bridge

There are a large number of damping materials in high-damping rubber (HDR) bearings, so the HDR bearings have the characteristics of both common rubber bearings and damping measures and show good aseismic effect. In this paper, the time-history dynamic analysis method is used to study the seismic effects of HDR bearings on the aseismic behaviors of two-span simply supported beam bridge under Northridge earthquake by changing the damping characteristics of the bearings. It is found that, with increasing damping of the bearings, both the horizontal shear and the displacement of the HDR bearings decrease, and the seismic energy dissipates through both the yield deformation and damping of the bearings. Although the girder and bearings have smaller displacement, when the HDR bearings with larger damping, the seismic responses, including displacement of pier top, shear force of pier bottom, and bending moment of pier bottom, are hardly affected by the change of the damping of the bearings. The HDR bearings with higher damping and yield characteristics separate and dissipate the seismic energy transmitted to the superstructure of the bridge and have better seismic effect on the structure in an earthquake.

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