Transcript Non-Contact Measurements Pre

A New
Real-Time, Non-Contact
Transfer-Length Measurement Technique
Inventors:
Dr. Terry Beck (Mechanical Engineering)
Dr. Robert Peterman (Civil Engineering)
Dr. John Wu (Industrial Engineering)
Weixin Zhao (Industrial Engineering)
What is the problem for which
you have a solution ?
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?
• 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
48 MPain
(7 Pretensioned
KSI) SLW Specimen with
1/2"-Special
FWC Strand
Strain
Concrete
Member
00
20
500
40
1000
60
1500
00
-200
-400
Microstrain
-600
At Transfer of Prestress
3 Days After Transfer
14 Days After Transfer
36 Days After Transfer
66 Days After Transfer
-800
-1000
-1200
-1400
-1600
-1800
Distance Along
AlongBeam
Beam(mm)
(cm)
Distance
80
2000
100
2500
What is our solution?
• Non-Contact Measurements
• Portable as Current Tool
• Much Higher Precision
• More Flexible
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?
Concrete beam cutting experiment
Prototype Design
Experiment Setup
Beam Cutting
Cutting Pretensioned Specimen
Comparison of Different Strain Gauges
Right Side
200.0
Whittemore 11-16
Optical 11-16
Microstrain
150.0
100.0
50.0
0.0
0
20
40
60
-50.0
Distance along beam(cm)
80
100
Prototype Specification
41/4 inches
8 in
Optical Sensor
Resolution: < 10me  1mm
Weight: 3 lbs
Dimension: 11”x6”x4”
Measurement speed: 15 samples/second
Concrete Cylinder Compression Experiment
Electronic
Strain
Gage
Optical
Strain
Gage
Concrete Cylinder Results
500
450
ESG at surface 1
400
Microstrain
350
Optical at surface 1
300
250
200
150
100
50
0
0
2000
4000
6000
8000
10000
Load (lbs)
12000
14000
16000
18000
20000
Concrete Cylinder Results
Differences Between Optical and ESG
7
6
5
Microstrain
4
3
2
1
0
-1 0
2000
4000
6000
8000
10000
-2
-3
-4
Load (lbs)
12000
14000
16000
18000
20000
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 Personnel
Have 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
Auto Measuring System
Measurement Surface
Sensor
Traverse
Delta Strain Rosette
Who specifically would be
a possible commercial partner or
licensee for your invention?
•Precision Optical Measurement Inc.
•Advanced Manufacturing Institute
Questions?