Programm Photovoltaik Ausgabe 2009 ... - Bundesamt für Energie BFE

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Figure 16: Flexible DSCmodule
Figure 17: Curved asymmetric
c-Si-honeycomb-carbon fiber composite
ultralight sandwich structure
(800 g/m 2 )
Figure 18: Multifunctional sandwich
panel
WP3. Endurance analysis of the multifunctional structure (resp. ICOM/CCLAB)
Task 9. Constitutive behavior of materials
The necessary tests for the determination of the constitutive behavior of the examined materials were
performed. Basic material properties were estimated. A database for CFRP, GFRP laminates, honeycomb
and polyurethane foam cores was established.
Tasks 10 & 11. Structural behavior under static and fatigue loads
Five lightweight sandwich modules were delivered by LTC to ICOM/CCLab for static testing (longitudinal,
transverse (and out-of-plane for honeycomb) moduli and strength). Specimens were instrumented
with strain gages in order to record resulted strains under tensile loads. Shear strength was determined
by performing 10° off-axis tests. Mechanical and elastic properties of the basic composite layer,
the unidirectional laminate and the honeycomb, have been derived. A device has been prepared in IS
for the application of bending loads for the mechanical testing, without crushing the solar cells (Figure
20). The quasi-static behavior of GFRP/PU foam-core sandwich panels with integrated solar cells
(either c-Si or flexcell modules) was investigated. Both of them were encapsulated on the top skin of
GFRP/PU foam sandwich panels. Mechanical (4-point bending) and thermal (sun simulation) tests
were performed on the manufactured panels to assess their structural integrity and evaluate the cell
encapsulation. The encapsulation did not considerably affect the efficiency of the cells. FE models
were developed by CCLab for the simulation of the structural and thermal behavior of the examined
panels. The activity on fatigue was cancelled due to lack of available experimental resources.
Figure 19: Experimental characterization oh honeycomb and
sandwich panel
Ultralight Photovoltaic Structures, Y. Leterrier, EPFL
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Figure 20: New 4-point bending
testing device