Citation: Ding, G.; Yan, X.; Gao, X.;
Xiao, J. Experimental and Numerical
Studies on Fatigue Characteristics of
CFRP Shaft Tube. Appl. Sci. 2022, 12,
8933. https://doi.org/10.3390/
app12188933
Academic Editor: Abílio Manuel
Pinho de Jesus
Received: 13 August 2022
Accepted: 2 September 2022
Published: 6 September 2022
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Article
Experimental and Numerical Studies on Fatigue Characteristics
of CFRP Shaft Tube
Guoping Ding
1,2,3
, Xiaoyu Yan
4
, Xiaoling Gao
4,
* and Jieliang Xiao
4
1
Institute of Advanced Material and Manufacturing Technology, Wuhan University of Technology,
Wuhan 430070, China
2
Hubei Key Laboratory of Digital Manufacturing, Wuhan University of Technology, Wuhan 430070, China
3
Hubei Provincial Engineering Technology Research Center for Magnetic Suspension, Wuhan University
of Technology, Wuhan 430070, China
4
School of Mechanical and Electrical Engineering, Wuhan University of Technology, Wuhan 430070, China
* Correspondence: xiaolingwhut@gmail.com; Tel.: +86-132-6299-2654
Abstract:
Carbon Fiber Reinforced Plastic (CFRP) shaft tube structure is widely applied in different
fields, including aerospace, automotive, and wind power. Since CFRP shaft tube is often subjected to
bending fatigue loads, it is of great significance to research its bending fatigue characteristics. Because
of its unique advantages, such as a smaller size, lighter weight, and the outstanding ability to form
a sensor network, the Fiber Bragg Grating (FBG) sensor is very applicable for health monitoring
research of composite material structures. Taking the CFRP shaft tube under bending load as the
research object, based on the theory of composite material mechanics and applying the research idea
of combining simulation analysis and experiment, the fatigue life, residual stiffness, and fatigue
damage evolution of CFRP tubes under three-point bending fatigue loading were studied. Moreover,
the fatigue characteristics of CFRP tubes under different fatigue loading were analyzed. At the same
time, the ultrasonic phased array was used to obtain the fatigue damage evolution rule by scanning
and analyzing the damage to the CFRP shaft tube after different fatigue loading times. Through the
application of the FBG sensors, the whole process of fatigue evolution of the CFRP shaft tube was
fully monitored.
Keywords:
CFRP shaft tube; three-point bending; fatigue characteristics; damage evolution; FBG
sensor; online monitoring
1. Introduction
Carbon Fiber Reinforced Plastic (CFRP) has the advantages of high specific strength,
fatigue resistance, corrosion resistance, and heat resistance. O’Dwyer et al. [
1
–
4
] described
how, due to their excellent properties, carbon fiber composite materials are widely used
in aerospace, new energy, rail transit, and other fields. However, the CFRP shaft tube
structure is often subjected to alternating loads during service. Although the stress is lower
than its ultimate strength, the internal micro-cracks will slowly expand, thereby causing
matrix cracking, delamination and fiber fracture, and other fatigue damages in the structure.
As a result, serious accidents are likely to be caused by the structural strength, stiffness,
and other mechanical properties of the attenuation, which brings hidden danger to the
use of composite components. Therefore, by exploring its fatigue characteristics under a
three-point bending fatigue load, and mastering its fatigue damage evolution mechanism,
it is of great significance to formulate timely inspection and maintenance strategies for
CFRP shaft tubes and improve the reliability and safety of the tubes during service.
At present, scholars both at home and abroad have done a lot of basic research on the
fatigue damage mode of composite materials, the evolution mechanism of fatigue damage,
fatigue life, and damage detection. He et al. [
5
] proposed that the three-point bending
fatigue characteristics of CFRP laminates under different fatigue load levels and fatigue
Appl. Sci. 2022, 12, 8933. https://doi.org/10.3390/app12188933 https://www.mdpi.com/journal/applsci
