Mass-normalized mode shape identification method for bridge structures using parking vehicle-induced frequency change

2018 ◽  
Vol 25 (6) ◽  
pp. e2174 ◽  
Author(s):  
Wen-Yu He ◽  
Wei-Xin Ren ◽  
Xiao-Han Zuo
Keyword(s):  
Mode Shape ◽  
Frequency Change ◽  
Shape Identification ◽  
Identification Method ◽  
Bridge Structures

Mass normalized mode shape identification of bridge structures using a single actuator-sensor pair

2018 ◽  
Vol 25 (11) ◽  
pp. e2244 ◽  
Author(s):  
Rajdip Nayek ◽  
Suparno Mukhopadhyay ◽  
Sriram Narasimhan
Keyword(s):  
Mode Shape ◽  
Shape Identification ◽  
Bridge Structures

scholarly journals Mass-Stiffness Combined Perturbation Method for Mode Shape Monitoring of Bridge Structures

2019 ◽  
Vol 2019 ◽  
pp. 1-14
Author(s):  
Liye Zhang ◽  
Ye Xia ◽  
Jose A. Lozano-Galant ◽  
Limin Sun
Keyword(s):  
Mode Shape ◽  
Experimental Tests ◽  
Mode Shapes ◽  
Shape Identification ◽  
Similar Frequency ◽  
Damage Scenarios ◽  
Perturbation Mode ◽  
Bridge Structures ◽  
Traditional Mode ◽  
The Relationship

Identification of the mode shapes through monitoring is one of the key problems in damage diagnosis based on modal parameters especially for damaged structures. In order to obtain mode shapes of damaged structures easily and accurately, the mass-stiffness combined perturbation (MSCP) method is proposed in this paper. To do so, the relationship between the stiffness perturbation mode shapes of damaged and intact structures is firstly derived and established. Then, the principle of similar frequency is applied to optimize the objective function of the most suitable mass perturbation model. Both numerical analyses and experimental tests on simple and complex structures demonstrate that the proposed MSCP method achieves higher precision than traditional mode shape identification methods. The additional advantages of the MSCP method include (i) lower requirement on the frequency analysis of only damaged structures and (ii) higher effectiveness for minor damage scenarios. In fact, the lower the damage, the higher the precision achieved by the MSCP method. As illustrated in the paper, the proposed technique has excellent applications in mode shapes identification and structural health monitoring.

Mode shape identification and orthogonalization

AIAA Journal ◽  
1990 ◽  
Vol 28 (4) ◽  
pp. 711-716 ◽  
Author(s):  
Alvar M. Kabe
Keyword(s):  
Mode Shape ◽  
Shape Identification

Effect of Peak Excitation Frequency on Seismic Fatigue Damage of Plant Pipelines

2020 ◽  
Author(s):  
Fumio Inada ◽  
Michiya Sakai ◽  
Ryo Morita ◽  
Ichiro Tamura
Keyword(s):  
Fatigue Damage ◽  
Mode Shape ◽  
Excitation Frequency ◽  
Peak Frequency ◽  
New Method ◽  
Vibration Velocity ◽  
Frequency Change ◽  
Concentrated Mass ◽  
Input Acceleration ◽  
Cumulative Fatigue Damage

Abstract In a previous report, a new method of calculating the approximate seismic cumulative fatigue damage of plant pipelines was developed, in which the sum of the cumulative absolute velocities (CAV) of the pipeline response per cycle was calculated, and the result was applied to the allowable vibration velocity described in the ASME Operation and Maintenance (O/M) code 2012. The new method provided a conservative value of cumulative fatigue damage. In this present study, a parameter showing the effect of a concentrated mass attached to the tip of a cantilever pipe was obtained as a function of the ratio of the concentrated mass to the mass of the cantilever pipe by eigenmode calculation using ABAQUS. In the previous report, the new method was based on the relative response of the pipeline, whereas in this present study, the application of the method was expanded to evaluations using the CAV of the excitation input for each cycle. We conducted the fast forward simulation of a real earthquake to determine the effect of the peak frequency change on cumulative fatigue damage, and we found that the response of cumulative fatigue damage at the peak frequency tends to decrease with increasing peak excitation frequency, which was consistent with the results obtained using the previously reported new method. Both the new method and the newly expended method are based on the ASME O/M code, and the results obtained by these methods suggest that the peak frequency tends to affect general pipelines. In the calculations, when the configuration of the pipeline is fixed and the mode shape does not change, the cumulative fatigue damage was found to decrease with increasing peak frequency of input acceleration. If the mode shape changes with the peak input acceleration frequency, then cumulative fatigue damage is affected. Moreover, if the participation factor has a larger value in a higher mode, the cumulative fatigue damage also has a larger value.

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