Deflection estimation of beam structures based on the measured strain mode shape

Author(s):  
Qing Zhang ◽  
Xing Fu ◽  
Liang Ren
2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Yong-Ying Jiang ◽  
Bing Li ◽  
Zhou-Suo Zhang ◽  
Xue-Feng Chen

Identification of structural crack location has become an intensely investigated subject due to its practical importance. In this paper, a hybrid method is presented to detect crack locations using wavelet transform and fractal dimension (FD) for beam structures. Wavelet transform is employed to decompose the mode shape of the cracked beam. In many cases, small crack location cannot be identified from approximation signal and detailed signals. And FD estimation method is applied to calculate FD parameters of detailed signals. The crack locations will be detected accurately by FD singularity of the detailed signals. The effectiveness of the proposed method is validated by numerical simulations and experimental investigations for a cantilever beam. The results indicate that the proposed method is feasible and can been extended to more complex structures.


2015 ◽  
Vol 22 (1) ◽  
pp. 86-91 ◽  
Author(s):  
Se Woon CHOI ◽  
Jihoon LEE ◽  
Byung Kwan OH ◽  
Hyo Seon PARK

The structural safety of a beam structure is assessed by a comparison between the maximum stress measured during monitoring and the allowable stress of the beam. However, the strain directly measured from a fiber Bragg grat- ing (FBG) strain sensor may not be identical with the actual maximum strain induced in the structural member. Unless a FBG strain sensor is installed exactly on where maximum strain occurs, the reliability of the evaluated safety based on the measured strain depends on the number and location of sensors. Therefore, in this paper, analytical models are presented for estimation of the maximum values of strains in a linear elastic beam using the local strains measured from FBG sensors. The model is tested in an experiment by comparing estimated maximum strain from FBG sensors and directly measured strain from electrical gages. For the assessment of safety of typical beam structures in buildings and infrastructures, analytical models for various loading and boundary conditions are provided.


2021 ◽  
Vol 37 (1) ◽  
pp. 25-32
Author(s):  
Jiangtao Ji ◽  
Kaikang Chen ◽  
Xin Jin ◽  
Jing Pang ◽  
Xing Chen ◽  
...  

Abstract. The vibration of agricultural machinery significantly influences driving comfort and operation reliability. In recent years, research on the vibrational characteristics of agricultural machinery has gradually expanded. To solve the problem of the obvious vibration of a high-speed transplanter under operating conditions, this article examines the method of beam damage diagnosis for high-speed transplanters based on the strain mode. Based on the modal theory, the displacement and strain modal analysis of the beam of the high-speed transplanter is performed. The analysis shows that the relative deviation of the modal frequencies of the same order before and after the beam is damaged is small. There is no obvious abrupt change in the displacement mode shape, while the strain mode shape has a sudden change peak after the beam is damaged. Thus, the strain mode change rate is constructed as a diagnostic index for beam damage. The analysis results show that the strain mode change rate increases with the increase in beam damage degree. Finally, the least squares method is used to fit the corresponding relationship between the two quantities. The results show that the strain mode change rate is sensitive and reliable as an index of damage diagnosis, which can better determine the location and degree of damage to the beam. Keywords: Beam, Damage, Diagnosis, Rice transplanter, Strain mode.


2018 ◽  
Vol 422 ◽  
pp. 112-130 ◽  
Author(s):  
Ning Guo ◽  
Zhichun Yang ◽  
Le Wang ◽  
Yan Ouyang ◽  
Xinping Zhang

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