Smart materials in BTeV?

Antonio Paolozzi

University of Rome ‘La Sapienza’

INFN Laboratori Nazionali Frascati

OBJECTIVE

Testing embedding Fiber Bragg Gratings (FBGs) into a Carbon Fiber Reinforced Plastic Composite (CFRP)

Manufacturing a smart material that could be used in some BTeV applications

POSSIBLE APPLICATIONS

• SUPPORT STRUCTURES OF MICROSTRIP

• SUPPORT OF OTHER DETECTORS

• LOW ATOMIC NUMBER AND HIGH MECHANICAL CHARACTERISTCS

• HIGH THERMAL STABILITY (VERY LOW THERMAL EXPANSION COEFFICIENT

• POSSIBILITY TO POSITION THE SENSORS IN ANY STRUCTURALLY SIGNIFICANT POINT IN THE STRUCTURE

• HIGHER RELIABILITY IN HANDLING SENSORIZED COMPONENTS

WHY CFRP WITH EMBEDDED SENSORS?

MANUFACTURING PHASES

DIFFERENT SPECIMENS TO TEST SEVERAL EMBEDDING PROCEDURES

•AVOID FIBER DAMAGE

•OBTAIN OPTIMAL BONDING BETWEEN OPTICAL FIBER

AND COMPOSITE STRUCTURE

Acrylate coated optical fiber Uncoated optical fiber

Micrographic analysis of embedded optical fiber

Micrographic analysis of optical fiber

embedded with epoxy resin film

Acrylate coated optical fiber Uncoated optical fiber

Experimental test

• Structural bonding between CFRP structure and FBG sensor

• FBG resolution (axial deformation) evaluation

3000 2000 1000 0 1000 2000 30000.2

0.1

0

0.1

0.2

Tip Displacement (micron)

Wav

elen

gth

Shi

f (n

m)

0.01 0.005 0 0.005 0.010.2

0.1

0

0.1

0.2

Axial deformation (micron)

Wav

elen

gth

Shi

f (n

m)

Enforced displacement at steps of 100m

Linearity: excellent FBG-CFRP structural bonding

Resolution of axial deformation by FBG: better than 0.5m

100 0 100 200 300 4000.01

0

0.01

0.02

0.03

Tip Displacement (micron)

Wav

elen

gth

Shif

(nm

)

PLANNED TEST

METALLIC BRACES HOLDING SUB-DETECTORS REPLACED BY CFRP SMART BRACES

CONCLUSIONS

•PERFECT BONDING BETWEEN FBGs AND CFRP WITH NO REDUCTION OF CFRP MECHANICAL CHARACTERISTICS