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) +

user manualsuser manuals