Using Fiber Bragg Gratings to Detect Damage in Metal Plates

School Name

Governor's School for Science & Mathematics

Grade Level

12th Grade

Presentation Topic

Engineering

Presentation Type

Mentored

Mentor

Mentor: Lingyu Yu, University of South Carolina

Abstract

Many aircraft in both the private and public sectors are facing serious aging issues. In the interest of making these aircraft as safe as possible and reducing maintenance costs, it is necessary to detect damage as early as possible. However, traditional methods often fail at early detection, especially in the case of composites, which are a principal building material of aircraft. The proposed solution is to pair fiber Bragg gratings (FBGs) with piezoelectric wafer active sensors (PWAS). PWAS produce guided ultrasonic waves (GUWs), which are then received and converted to an analog electrical signal by FBGs. Three procedures were performed with PWAS and FBG. The first was a directionality test, used to establish a baseline for the mechanics of GUW based damage detection. The second was a sensitivity test, which measured the effect of changing the orientation of a PWAS relative to the FBG and testing a signal difference. The final procedure was a classic damage detection problem, in which an obstruction was placed on the plate and the reflections emanating from this damage source were isolated. Results of the first procedure closely matches the results of previous studies, suggesting that the PWAS and FBG were set up correctly in that case and in future procedures. For both the second and third procedure, increasing frequency consistently correlated with decreasing signal to noise ratio. The data appears to imply that lower frequencies are better for damage detection, but further research is needed.

Location

Wall 223

Start Date

3-25-2017 12:15 PM

Presentation Format

Oral and Written

Group Project

No

COinS
 
Mar 25th, 12:15 PM

Using Fiber Bragg Gratings to Detect Damage in Metal Plates

Wall 223

Many aircraft in both the private and public sectors are facing serious aging issues. In the interest of making these aircraft as safe as possible and reducing maintenance costs, it is necessary to detect damage as early as possible. However, traditional methods often fail at early detection, especially in the case of composites, which are a principal building material of aircraft. The proposed solution is to pair fiber Bragg gratings (FBGs) with piezoelectric wafer active sensors (PWAS). PWAS produce guided ultrasonic waves (GUWs), which are then received and converted to an analog electrical signal by FBGs. Three procedures were performed with PWAS and FBG. The first was a directionality test, used to establish a baseline for the mechanics of GUW based damage detection. The second was a sensitivity test, which measured the effect of changing the orientation of a PWAS relative to the FBG and testing a signal difference. The final procedure was a classic damage detection problem, in which an obstruction was placed on the plate and the reflections emanating from this damage source were isolated. Results of the first procedure closely matches the results of previous studies, suggesting that the PWAS and FBG were set up correctly in that case and in future procedures. For both the second and third procedure, increasing frequency consistently correlated with decreasing signal to noise ratio. The data appears to imply that lower frequencies are better for damage detection, but further research is needed.