LMAF / EPFL LMAF / EPFL What's new? What's new? Tested 9 specimens (3 plates, 1mm joint): Tested 9 specimens (3 plates, 1mm joint): 2 cameras -> local / global deformations 2 cameras -> local / global deformations variability of yield stress / ultimate stress variability of yield stress / ultimate stress (Ultimate load range from 775 to 1050 N) (Ultimate load range from 775 to 1050 N) still 6 specimens (1mm) to test => data analysis & still 6 specimens (1mm) to test => data analysis & identification identification machining of the other samples : 2 weeks delay... machining of the other samples : 2 weeks delay... Optical measurements: Optical measurements: found a method to remove the effects of the out of plane found a method to remove the effects of the out of plane displacements for optical strain measurement displacements for optical strain measurement finished the 2D strain field measurement algorithm finished the 2D strain field measurement algorithm Identification method: Identification method: improvement of the method (optimization methods with/without improvement of the method (optimization methods with/without bounds) bounds) development of a simple user interface development of a simple user interface improvement of the parametric joint finite element model (mesh, improvement of the parametric joint finite element model (mesh, outputs...) outputs...)
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LMAF / EPFL What's new? Tested 9 specimens (3 plates, 1mm joint): 2 cameras -> local / global deformations 2 cameras -> local / global deformations variability.
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LMAF / EPFLLMAF / EPFLWhat's new?What's new?
Tested 9 specimens (3 plates, 1mm joint):Tested 9 specimens (3 plates, 1mm joint): 2 cameras -> local / global deformations2 cameras -> local / global deformations variability of yield stress / ultimate stressvariability of yield stress / ultimate stress
(Ultimate load range from 775 to 1050 N)(Ultimate load range from 775 to 1050 N) still 6 specimens (1mm) to test => data analysis & identification still 6 specimens (1mm) to test => data analysis & identification machining of the other samples : 2 weeks delay...machining of the other samples : 2 weeks delay...
Optical measurements:Optical measurements: found a method to remove the effects of the out of plane displacements for found a method to remove the effects of the out of plane displacements for
optical strain measurementoptical strain measurement finished the 2D strain field measurement algorithmfinished the 2D strain field measurement algorithm
Identification method:Identification method: improvement of the method (optimization methods with/without bounds)improvement of the method (optimization methods with/without bounds) development of a simple user interfacedevelopment of a simple user interface improvement of the parametric joint finite element model (mesh, outputs...)improvement of the parametric joint finite element model (mesh, outputs...)
LMAF / EPFLLMAF / EPFL1mm Joints1mm Joints
Load-displacement curves
0
200
400
600
800
1000
1200
0 0.05 0.1 0.15 0.2 0.25 0.3
Displacement
Lo
ad
1A
1B
1C
2A
2B
2C
3A
3B
3C
LeadfreeB2: stress-strain relation, with correction of the out of plane component
0.00E+00
5.00E+06
1.00E+07
1.50E+07
2.00E+07
2.50E+07
3.00E+07
3.50E+07
4.00E+07
4.50E+07
5.00E+07
-0.50% 0.00% 0.50% 1.00% 1.50% 2.00%
Strain
Str
es
s
Strain X
Strain Y1
Corrected Strain X
Strain Y2
LMAF / EPFLLMAF / EPFL2D Digital Image Correlation2D Digital Image Correlation
LMAF / EPFLLMAF / EPFLWhat's next?What's next?
TestingTesting 1mm specimens:1mm specimens:
test the last 6 specimens test the last 6 specimens
process the data (plasticity evolution, deformation analysis, stress-strain curves)process the data (plasticity evolution, deformation analysis, stress-strain curves)
sort the measurements and identify constitutive parameters => statisticssort the measurements and identify constitutive parameters => statistics 0.5 mm & 0.25mm specimens:0.5 mm & 0.25mm specimens:
after machining: send back 4x3 specimens to EMPA for X-Ray analysis (voids?)after machining: send back 4x3 specimens to EMPA for X-Ray analysis (voids?)
test the other 0.5 mm samples & process data test the other 0.5 mm samples & process data
check if optical measurement technique is sensitive enough for 0.25 mm jointscheck if optical measurement technique is sensitive enough for 0.25 mm joints
identify the constitutive parameters for 0.5 mm jointsidentify the constitutive parameters for 0.5 mm joints
finally test & process the data for 0.25mm jointsfinally test & process the data for 0.25mm joints
send all the samples back to EMPA for fractographic analysissend all the samples back to EMPA for fractographic analysis
Developments:Developments: finish the user interface of the identification method (=> Matlab package) + finish the user interface of the identification method (=> Matlab package) +