Title page for ETD etd-111097-14850


Type of Document Master's Thesis
Author Raju, Vinod
Author's Email Address vraju@mail.vt.edu
URN etd-111097-14850
Title Implementing Impedance - Based Health Monitoring
Degree Master of Science
Department Mechanical Engineering
Advisory Committee
Advisor Name Title
Cudney, Harley H. Committee Chair
Duke, John C. Jr. Committee Member
Lalande, Frederic Committee Member
Keywords
  • Impedance-based health monitoring
  • Smart structures
  • Piezoelectric actuator/sensor patches
  • global NDE technique
  • health monitoring of composite-reinforced concret
Date of Defense 1997-11-14
Availability unrestricted
Abstract
This work is an experimental study of applying an impedance-based health monitoring technique to complex structures. The work is presented in three parts.

In the first part we consider effects of the following three factors on damage detection abilities: actuator excitation level, test wire length and ambient conditions (temperature, structural loading and vibration). It was concluded that increasing the applied voltage improves the signal to noise ratio and damage detection abilities. Test wire lengths under 30m do not affect damage detection abilities. The technique is able to distinguish and detect damage even with variations in temperature, structural loading and vibration.

In the second part we apply our health monitoring technique to a complex truss structure and a massive steel steam header. We discovered that with multiplexing (acquiring a single signal from distributed actuators) the actuators on the truss structure we could detect damage but with less location information. Damage detection on the steel pipe ended in inconclusive results. The use of this technique on massive structures needs further investigation.

Finally, we conducted a detailed experimental study of monitoring the integrity of composite-reinforced masonry structures. We developed a software package which enables even a casual user to determine if significant damage has occurred in these structures. The technique was successfully applied to detect damage (particularly due to delamination) in these composite-concrete structures. Most significantly, the technique was also able to detect damage well in advance of actual failure.

This work relies mainly on frequency response plots and damage metric charts to present the data and to arrive at any conclusions. While frequency response plots give a qualitative approach to the analysis, damage metric charts attempt to quantify the data.

Files
  Filename       Size       Approximate Download Time (Hours:Minutes:Seconds) 
 
 28.8 Modem   56K Modem   ISDN (64 Kb)   ISDN (128 Kb)   Higher-speed Access 
  APP-A.PDF 702.45 Kb 00:03:15 00:01:40 00:01:27 00:00:43 00:00:03
  APP-B.PDF 20.86 Kb 00:00:05 00:00:02 00:00:02 00:00:01 < 00:00:01
  APP-C.PDF 20.99 Kb 00:00:05 00:00:02 00:00:02 00:00:01 < 00:00:01
  APP-D.PDF 11.37 Kb 00:00:03 00:00:01 00:00:01 < 00:00:01 < 00:00:01
  APP-E.PDF 5.75 Kb 00:00:01 < 00:00:01 < 00:00:01 < 00:00:01 < 00:00:01
  APP-F.PDF 5.15 Kb 00:00:01 < 00:00:01 < 00:00:01 < 00:00:01 < 00:00:01
  CHAPTE_1.PDF 109.64 Kb 00:00:30 00:00:15 00:00:13 00:00:06 < 00:00:01
  CHAPTE_2.PDF 54.04 Kb 00:00:15 00:00:07 00:00:06 00:00:03 < 00:00:01
  CHAPTE_3.PDF 213.49 Kb 00:00:59 00:00:30 00:00:26 00:00:13 00:00:01
  CHAPTE_4.PDF 292.67 Kb 00:01:21 00:00:41 00:00:36 00:00:18 00:00:01
  CHAPTE_5.PDF 246.27 Kb 00:01:08 00:00:35 00:00:30 00:00:15 00:00:01
  CHAPTE_6.PDF 152.32 Kb 00:00:42 00:00:21 00:00:19 00:00:09 < 00:00:01
  CHAPTE_7.PDF 967.77 Kb 00:04:28 00:02:18 00:02:00 00:01:00 00:00:05
  CHAPTE_8.PDF 21.12 Kb 00:00:05 00:00:03 00:00:02 00:00:01 < 00:00:01
  ETD.PDF 40.92 Kb 00:00:11 00:00:05 00:00:05 00:00:02 < 00:00:01
  REFERE_1.PDF 10.84 Kb 00:00:03 00:00:01 00:00:01 < 00:00:01 < 00:00:01
  VITA.PDF 91.74 Kb 00:00:25 00:00:13 00:00:11 00:00:05 < 00:00:01

Browse All Available ETDs by ( Author | Department )

dla home
etds imagebase journals news ereserve special collections
virgnia tech home contact dla university libraries

If you have questions or technical problems, please Contact DLA.