Experimental study of dynamic strain for gear tooth using fiber Bragg gratings and piezoelectric strain sensors

Yongzhi Qu, Liu Hong, Xixin Jiang, Miao He, David He, Yuegang Tan, Zude Zhou

Research output: Contribution to journalArticlepeer-review

16 Scopus citations


It has always been a critical task to understand gear dynamics for gear design and condition monitoring. Many gear models have been proposed to simulate gear meshing dynamics. However, most of the theoretical models are based on simplified gear structure and may contain approximation errors. Direct measuring of gear strain is important for gear design validation, load analysis, reliability assessment, gear condition monitoring, etc. Most of the existing studies of tooth strain measurements are performed under static load condition. In this paper, we investigate new measuring techniques using fiber Bragg grating sensor and piezoelectric strain for gear dynamic strain measurement. We conduct gear dynamic strain measurement under both normal and pitted conditions to evaluate the strain transition process and pitting effect. The experiments are performed on an industrial gearbox with relatively small module gears. Multiple combinations of speed and load conditions are tested and the results are discussed and analyzed. We analyze multiple factors that affect the tooth root stress, including speed, load, extended tooth meshing, etc. It is found that under low operation speed range, the tooth root strain is mainly determined by the torque, while in the medium to high speed range, the tooth root strain is jointly affected by speed and torque. Extended tooth contact is shown in the measurement results with strong evidence. It conforms to earlier founding that the transmission error and dynamic load factor are overestimated for spur gear under heavy load. We also evaluate the change in dynamic strain caused by pitted tooth surface. It is shown that pitting faults lead to decreased bending strain on the tooth, especially in single-tooth contact zone, which represents a loss in torque and possibly reduced mesh stiffness. Numerical simulations are also provided to make comparisons and help to interpret the experimental results.

Original languageEnglish (US)
Pages (from-to)3992-4003
Number of pages12
JournalProceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science
Issue number21
StatePublished - Nov 1 2018
Externally publishedYes

Bibliographical note

Funding Information:
The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was partially supported by NSFC (51505353) and NSFC (51605349), and NSF of Hubei Province (2016CFB584).

Funding Information:
The authors would like to thank Dr Hui Ma at Northeast University (China) for helpful discussion and the anonymous reviewers for their helpful comments and suggestions.

Publisher Copyright:
© IMechE 2017.

Copyright 2018 Elsevier B.V., All rights reserved.


  • Dynamic strain
  • extended tooth contact
  • fiber Bragg grating
  • piezoelectric strain sensors
  • pitting
  • time-varying mesh stiffness


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