Strain Response Frequency Function-Based Mechanical Damage Indentification by Fiber Bragg Grating Sensors

Author(s):  
Mingyao Liu ◽  
Menglong Ke ◽  
Zude Zhou ◽  
Yuegang Tan
2020 ◽  
pp. 073168442095811
Author(s):  
Yannick Blößl ◽  
Gergely Hegedüs ◽  
Gábor Szebényi ◽  
Tamás Tábi ◽  
Ralf Schledjewski ◽  
...  

This article examines the use of fiber Bragg grating sensors for cure monitoring purposes in resin transfer molding processes. Within a resin transfer molding test series a thermoset epoxy-amine resin system was used in combination with a woven flax fiber reinforcement. Particular attention was paid on the location of the optical fiber sensor and its sensitive Bragg grating element inside the mold cavity. Three different installation approaches were tested and the correlation of the corresponding strain response with the actual cure state of the resin system was investigated at 50°C and 70°C isothermal cure temperature, respectively. We could demonstrate that characteristic, conspicuous strain changes are directly related to the sol–gel conversion of the thermoset polymer, which was analyzed considering different approaches for the gel-point detection based on rheological measurements. With the installation of the sensor inside a controllable, capsuled resin volume, we could achieve the most reliable strain response that provides capabilities to give in-situ information of the cure state beyond the gelation point.


Author(s):  
K. C. Liu ◽  
Cris Hiche ◽  
Aditi Chattopadhyay

In this paper, the dynamic Fiber Bragg Grating sensor response due to low speed impact on woven fiber composite plates was used to determine the extent of the impact damage. Three types of woven fabrics were considered in this study: plain, twill and 5 harness satin. A brief finite element analysis was used to determine the optimal location for the sensors. The bottom of the plate showed the highest strain response and was chose as the optimal location. The composite plates were fabricated and Fiber Bragg Grating sensors were mounted in the optimal location. The plates were subject to various impact energies using a modified Charpy impactor. The impact damage for each plate due to different impact energies was quantified through flash thermography and correlated with the FBG response. The flash thermography results showed excellent progression of damage in the plates and the sensor strain response was able to distinguish the impacts by considering both peak and plastic strain.


Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4272
Author(s):  
Oscar de la Torre ◽  
Ignazio Floris ◽  
Salvador Sales ◽  
Xavier Escaler

The present paper assesses the performance and characteristics of fiber Bragg grating sensors, with a special interest in their applications in hydraulic machinery and systems. The hydropower industry is turning to this technology with high expectations of obtaining high quality data to validate and calibrate numerical models that could be used as digital twins of key assets, further strengthening the sector’s relevant position within industry 4.0. Prior to any validation, fiber Bragg grating sensors’ ability to perform well underwater for long periods of time with minimal degradation, and their ease of scalability, drew the authors´ attention. A simplified modal analysis of a partially submerged beam is proposed here as a first step to validate the potential of this type of technology for hydropower applications. Fiber Bragg grating sensors are used to obtain the beam’s natural frequencies and to damp vibrations under different conditions. The results are compared with more established waterproof electric strain gauges and a laser vibrometer with good agreement. The presence of several sensors in a single fiber ensures high spatial resolution, fundamental to precisely determine vibration patterns, which is a main concern in this industry. In this work, the beam’s vibration patterns have been successfully captured under different excitations and conditions.


2016 ◽  
Author(s):  
Saurabh Kumar ◽  
V. Shrikanth ◽  
Bharadwaj Amrutur ◽  
Sundarrajan Asokan ◽  
M. S. Bobji

1999 ◽  
Author(s):  
Francisco M. Araujo ◽  
M. Teixeira ◽  
Luis A. A. Ferreira ◽  
Ireneu M. Dias ◽  
A. Quintela ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document