a new real-time, non-contact transfer-length measurement technique dr. terry beck (mechanical...
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A New A New Real-Time, Non-Contact Real-Time, Non-Contact
Transfer-Length Measurement TechniqueTransfer-Length Measurement Technique
Dr. Terry Beck (Mechanical Engineering)Dr. Terry Beck (Mechanical Engineering)
Dr. Robert Peterman (Civil Engineering)Dr. Robert Peterman (Civil Engineering)
Dr. John Wu (Industrial Engineering)Dr. John Wu (Industrial Engineering)
Weixin Zhao (Industrial Engineering)Weixin Zhao (Industrial Engineering)
Inventors:Inventors:Inventors:Inventors:
What is the problem for which you have a solution ?
What is the problem for which you have a solution ?
Why Measure Transfer Length?Why Measure Transfer Length?
• Used for calculation of shear capacity• Used for calculation of stresses• Has been shown to often be a good indicator
of strand development length• Could be used as a tool to screen out
potentially poor-bonding mixes
How is the problem being solved now?
What’s wrong with current solutions?
We simply don’t measure it?
Why Don’t We Measure Transfer Length at the Present Time?
Why Don’t We Measure Transfer Length at the Present Time?
• There is currently not a convenient or time-efficient method to get this information
• The current method(s) interrupt the daily casting and de-tensioning sequence
Current Tool
Whittemore Gauge
4 8 M P a ( 7 K S I ) S L W S p e c im e n w i t h 1 /2 " - S p e c ia l F W C S t r a n d
- 1 8 0 0
- 1 6 0 0
- 1 4 0 0
- 1 2 0 0
- 1 0 0 0
- 8 0 0
- 6 0 0
- 4 0 0
- 2 0 0
0
0 2 0 4 0 6 0 8 0 1 0 0
D is t a n c e A lo n g B e a m ( c m )
Mic
rost
rain
A t T r a n s f e r o f P r e s t r e s s
3 D a y s A f te r T r a n s f e r
1 4 D a y s A f te r T r a n s f e r
3 6 D a y s A f te r T r a n s f e r
6 6 D a y s A f te r T r a n s f e r
00 5 0 0 1 0 0 0 1 5 0 0 2 0 0 0 2 5 0 0
D i s t a n c e A l o n g B e a m ( m m )
4 8 M P a ( 7 K S I ) S L W S p e c im e n w i t h 1 /2 " - S p e c ia l F W C S t r a n d
- 1 8 0 0
- 1 6 0 0
- 1 4 0 0
- 1 2 0 0
- 1 0 0 0
- 8 0 0
- 6 0 0
- 4 0 0
- 2 0 0
0
0 2 0 4 0 6 0 8 0 1 0 0
D is t a n c e A lo n g B e a m ( c m )
Mic
rost
rain
A t T r a n s f e r o f P r e s t r e s s
3 D a y s A f te r T r a n s f e r
1 4 D a y s A f te r T r a n s f e r
3 6 D a y s A f te r T r a n s f e r
6 6 D a y s A f te r T r a n s f e r
00 5 0 0 1 0 0 0 1 5 0 0 2 0 0 0 2 5 0 0
D i s t a n c e A l o n g B e a m ( m m )
Strain in Pretensioned Concrete Member
What is our solution? What is our solution?
• Non-Contact Measurements
• Portable as Current Tool
• Much Higher Precision
• More Flexible
Surface Film Planeor Detector
Coherent LightSource
In Phase-Bright Speckle
Out of Phase-Dark Speckle
Concept of Laser Speckle
Photograph of Laser Speckle on Concrete
Peak Distances vs. Strains Measures
0.02mm deflection 0.10mm deflection 0.20mm deflection
Actual experimental work
we have performed? Actual experimental work
we have performed?
Concrete beam cutting experiment
Prototype Design
Experiment SetupBeam Cutting
Cutting Pretensioned Specimen
Comparison of Different Strain Gauges
Right Side
-50.0
0.0
50.0
100.0
150.0
200.0
0 20 40 60 80 100
Distance along beam(cm)
Mic
ros
tra
in
Whittemore 11-16
Optical 11-16
Diode Laser
Beam Expander
Speckle Pattern Images
CCD Camera
Mirror
Mirror
Mirror
Tested Surface
50/50 Beam Splitter
Strain
The New Device
Prototype Specification
41/4 inches
8 in
Resolution: < 10m
Weight: 3 lbs
Dimension: 11”x6”x4”
Measurement speed: 15 samples/second
Optical Sensor
Concrete Cylinder Compression Experiment
Electronic Strain Gage
Optical Strain Gage
Concrete Cylinder Results
0
50
100
150
200
250
300
350
400
450
500
0 2000 4000 6000 8000 10000 12000 14000 16000 18000 20000
Load (lbs)
Mic
rost
rain
ESG at surface 1
Optical at surface 1
Concrete Cylinder Results
Differences Between Optical and ESG
-4
-3
-2
-1
0
1
2
3
4
5
6
7
0 2000 4000 6000 8000 10000 12000 14000 16000 18000 20000
Load (lbs)
Mic
rost
rain
What is the closest prior art that might be
cited against the novelty of your invention?
None !
What Still Needs to Be Done?
• Continue to Gather SCC Mix Ingredients
• Cast Pretensioned Transfer-Length Specimens Members from 5 mixes used in SCC bond study
• Compare Whittemore Gage Results with Optical Results
Additional K-State PersonnelHave Been Added
• Commercialization Manager.
• 2 MBA Students (Final Project).
• Product Design Engineer.
• 2 Other Design Engineers (Optics and Electrical).
• Precision Optical Measurements, Inc.
The Goal
• Version 1 available for use this summer.
• For sale within one year (Approx. $20k)
The Future
Measurement Surface
Traverse
Sensor
Auto Measuring System
Delta Strain Rosette
Who specifically would be a possible commercial partner or
licensee for your invention?
•Precision Optical Measurement Inc.
•Advanced Manufacturing Institute
Questions?