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Evaluation of Damage in Cellulose Fiber Reinforced Concrete using Acoustic Emission

Permanent Link: http://ufdc.ufl.edu/UFE0041227/00001

Material Information

Title: Evaluation of Damage in Cellulose Fiber Reinforced Concrete using Acoustic Emission
Physical Description: 1 online resource (175 p.)
Language: english
Creator: Chen, Yu
Publisher: University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 2010

Subjects

Subjects / Keywords: acoustic, fiber
Civil and Coastal Engineering -- Dissertations, Academic -- UF
Genre: Civil Engineering thesis, Ph.D.
bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
born-digital   ( sobekcm )
Electronic Thesis or Dissertation

Notes

Abstract: The objectives of the research program were to evaluate the damage effect of aqueous effects and fatigue loading on the performance of Cellulose Fiber Reinforced Concrete (CFRC) and to develop a reliable inspection methodology using acoustic emission (AE) to identify the failure mechanism. ASTM third-point bending tests were conducted on CFRC beams; both monotonic loading and fatigue loading are executed. The AE data were collected and compared using visual observations from a Scanning Electronic Microscope to identify failure mechanisms at various damage levels. The failure mechanisms were determined to be matrix cracking, fiber/matrix debonding and fiber breakage. These fracture mechanisms were found to associate with low, middle and high amplitudes, respectively. The knowledge of fracture mechanisms was then applied to identify the effect of various aqueous conditions towards CFRC s properties and the material s fatigue property. ASTM three-edge-bearing test was conducted on pipe sections using AE. Data analysis was made by correlating mechanical property and AE results. Various methods were used to interpret the AE signals. Analysis of conventional AE parameters including hits, counts, energy and signal strength shows that AE can give real-time inspection of the internal damages, both minor and visible. Methods of AE amplitude distribution, AE cumulative amplitude distribution and b-value are powerful tools to discern fracture mechanisms. Duration vs. amplitude plot, on the other hand, proved to be useful in interpreting the quality of AE data and distinguishing friction data from valid data. In summary, the fracture mechanism, aqueous effects and fatigue property of CFRC were studied. The AE analysis methodology developed in this research program are believed to be reliable in the future inspection on structures made of CFRC material.
General Note: In the series University of Florida Digital Collections.
General Note: Includes vita.
Bibliography: Includes bibliographical references.
Source of Description: Description based on online resource; title from PDF title page.
Source of Description: This bibliographic record is available under the Creative Commons CC0 public domain dedication. The University of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Statement of Responsibility: by Yu Chen.
Thesis: Thesis (Ph.D.)--University of Florida, 2010.
Local: Adviser: Bloomquist, David G.

Record Information

Source Institution: UFRGP
Rights Management: Applicable rights reserved.
Classification: lcc - LD1780 2010
System ID: UFE0041227:00001

Permanent Link: http://ufdc.ufl.edu/UFE0041227/00001

Material Information

Title: Evaluation of Damage in Cellulose Fiber Reinforced Concrete using Acoustic Emission
Physical Description: 1 online resource (175 p.)
Language: english
Creator: Chen, Yu
Publisher: University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 2010

Subjects

Subjects / Keywords: acoustic, fiber
Civil and Coastal Engineering -- Dissertations, Academic -- UF
Genre: Civil Engineering thesis, Ph.D.
bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
born-digital   ( sobekcm )
Electronic Thesis or Dissertation

Notes

Abstract: The objectives of the research program were to evaluate the damage effect of aqueous effects and fatigue loading on the performance of Cellulose Fiber Reinforced Concrete (CFRC) and to develop a reliable inspection methodology using acoustic emission (AE) to identify the failure mechanism. ASTM third-point bending tests were conducted on CFRC beams; both monotonic loading and fatigue loading are executed. The AE data were collected and compared using visual observations from a Scanning Electronic Microscope to identify failure mechanisms at various damage levels. The failure mechanisms were determined to be matrix cracking, fiber/matrix debonding and fiber breakage. These fracture mechanisms were found to associate with low, middle and high amplitudes, respectively. The knowledge of fracture mechanisms was then applied to identify the effect of various aqueous conditions towards CFRC s properties and the material s fatigue property. ASTM three-edge-bearing test was conducted on pipe sections using AE. Data analysis was made by correlating mechanical property and AE results. Various methods were used to interpret the AE signals. Analysis of conventional AE parameters including hits, counts, energy and signal strength shows that AE can give real-time inspection of the internal damages, both minor and visible. Methods of AE amplitude distribution, AE cumulative amplitude distribution and b-value are powerful tools to discern fracture mechanisms. Duration vs. amplitude plot, on the other hand, proved to be useful in interpreting the quality of AE data and distinguishing friction data from valid data. In summary, the fracture mechanism, aqueous effects and fatigue property of CFRC were studied. The AE analysis methodology developed in this research program are believed to be reliable in the future inspection on structures made of CFRC material.
General Note: In the series University of Florida Digital Collections.
General Note: Includes vita.
Bibliography: Includes bibliographical references.
Source of Description: Description based on online resource; title from PDF title page.
Source of Description: This bibliographic record is available under the Creative Commons CC0 public domain dedication. The University of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Statement of Responsibility: by Yu Chen.
Thesis: Thesis (Ph.D.)--University of Florida, 2010.
Local: Adviser: Bloomquist, David G.

Record Information

Source Institution: UFRGP
Rights Management: Applicable rights reserved.
Classification: lcc - LD1780 2010
System ID: UFE0041227:00001


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Full Text

PAGE 17

Background

PAGE 18

Problem Statement Objectives Scope Dissertation Structure

PAGE 21

Cellulose Fiber Reinforced Concrete Material Constitution Manufacturing

PAGE 22

Acoustic Emission Introduction to Acoustic Emission

PAGE 23

Acoustic Emission Apparatus Transducer Receiver/amplifier

PAGE 24

Signal processors Transient digitizers

PAGE 25

Display coupling agent Acoustic Wave Propagation Theory

PAGE 26

Noise Discrimination

PAGE 27

5 thiAA 2 iD 10 thiAA 5.3 iD 15 thiAA 5.4 iD 5.0 iT 5.0 iT iA thA iD iT Typical Acoustic Emission Parameters

PAGE 28

Threshold: Count: Amplitude (Peak Amplitude): refV V A log20

PAGE 29

refVV 1 Duration: Rise time: Signal Strength: 2 1 2 1)( 2 1 )( 2 10t t t tdttfdttfS f f 1t 2tMARSE:

PAGE 30

2 1)( 2 1t t r rdttfS rf Energy : 2 1 2 1)( 2 1 )( 2 12 2 t t t t tdttfdttfE Hit: Event: Kaiser Effect: Felicity Effect:

PAGE 31

loadimum previous occur emissions whichatload Ratio Felicity max Historic index: N i oi N Ki oiS S KN N tH1 1)( oiS Severity: J i om rS J S11

PAGE 32

rS omS Scanning Electron Microscope SEM Testing

PAGE 33

Sample Preparation SEM Applications

PAGE 34

Fracture Mechanism of Fiber R einforced Composites in the Literature

PAGE 35

Fracture Mechanism of Fiber Reinforced Composites and AE Parameters

PAGE 36

Analysis of AE Amplitude Distribution ,,

PAGE 37

Cumulative Amplitude Distri bution and b-value Theory Theory of b-value refV V A log20

PAGE 38

refV V 1 )( V)( V)()(0VNVF 0N (0V0V 1) bV V V 0)( bV V NVF 0 0)( 0 0log log)(log N V V bVF 0 0log)()(log NAABAF

PAGE 39

CBAAF )(log 20 b B Summary

PAGE 41

3/ ftlbs

PAGE 51

Introduction Experimental Program

PAGE 52

Physical Results SEM Results Specimen SEM1 (70% of the ultimate load)

PAGE 53

Specimen SEM2 (95% of the ultimate load) Specimen SEM3 (100% of the ultimate load) AE Results

PAGE 54

Discussion

PAGE 56

)10(3

PAGE 62

Experimental Program Specimen Preparation

PAGE 63

F575 F149 F575Load Procedure

PAGE 64

Calculation of stresses and deflections 2bd Plt EI Pl centerat 56 ) max(3 EI Pl spoloadat 324 5 )int max(3 Testing Facilities Fracture Mechanism Analysis

PAGE 65

yP

PAGE 68

Conventional AE Data Analysis

PAGE 70

Amplitude versus Duration

PAGE 71

Amplitude Distribution

PAGE 72

Progression of Amplitude Distribution

PAGE 73

Cumulative Amplitude Di stribution and b-value

PAGE 74

Progression of Cumulative Amplitude Distribution Summary

PAGE 76

)10(3

PAGE 107

Experimental Program Specimens Preparation Load Procedure Testing Facilities

PAGE 108

CFRC Fatigue Life Identification of AE Resulting from Friction

PAGE 109

Mechanical Parameters to Identify the Damage Process

PAGE 111

Conventional AE Anal ysis Maximum Load = 2,000 lbs

PAGE 112

Maximum Load = 1,800 lbs Maximum Load = 1,600 lbs Amplitude Distribution Analysis

PAGE 114

Summary

PAGE 141

Experimental Program Specimens Preparation Load Procedure

PAGE 142

Testing Facilities Monotonic Loading Test on Dry Specimen Failure Process Study

PAGE 144

AE Data Analysis Conventional AE Analysis Amplitude Distribution Analysis

PAGE 145

Progression of Amplitude Distribution Cumulative Amplitude Distribution Progression of Cumulative Amplitude Distribution Summary on AE Data Analysis

PAGE 146

Cyclic Loading Test AE Data Analy sis Amplitude and Load versus Time

PAGE 147

Conventional AE Data Analysis Cumulative Amplitude Distribution

PAGE 148

Kaiser and Felicit y Effects Summary

PAGE 168

Conclusions

PAGE 170

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