40
4 Mechanical characterization on constituent level
indicate little over all scatter and reflect the typical curve progression of honeycomb
compression tests. The focus of the present study is on the stress-strain relationship up
until a strain of about 0.2. This enables the consideration of the initial stiffness, peak
stress and the following plateau stress. The behavior of the final densification phase is
not presented here, since it was not relevant for the scope of this thesis.
a)
b)
Figure 32 a) Experimental setup compressive tests; b) determined stress strain relationships
Flatwise tension
This test method primarily allows to determine the flatwise tensile modulus and strength
of a sandwich core. In case a bonded sandwich panel is tested it may also enable to determine the bond between core and face sheets. In this test, the specimens are subjected
to a tensile load normal to the sandwich plane, by means of self-aligned rigid loading
plates in order to ensure centric load transmission. In the present work, the relative disTable 6 Summary of performed flatwise compression tests
Test standard
ASTM C 365 [AST00]
Specimen dimension 60 mm x 60 mm x18.5 mm
Loading rate
1 mm/min
Testing machine
Shimadzu AG 25TB
Load cell
Shimadzu SFL-25AG (25kN)
Disp. measurement
Machine crosshead stroke
4 Mechanical characterization on constituent level
indicate little over all scatter and reflect the typical curve progression of honeycomb
compression tests. The focus of the present study is on the stress-strain relationship up
until a strain of about 0.2. This enables the consideration of the initial stiffness, peak
stress and the following plateau stress. The behavior of the final densification phase is
not presented here, since it was not relevant for the scope of this thesis.
a)
b)
Figure 32 a) Experimental setup compressive tests; b) determined stress strain relationships
Flatwise tension
This test method primarily allows to determine the flatwise tensile modulus and strength
of a sandwich core. In case a bonded sandwich panel is tested it may also enable to determine the bond between core and face sheets. In this test, the specimens are subjected
to a tensile load normal to the sandwich plane, by means of self-aligned rigid loading
plates in order to ensure centric load transmission. In the present work, the relative disTable 6 Summary of performed flatwise compression tests
Test standard
ASTM C 365 [AST00]
Specimen dimension 60 mm x 60 mm x18.5 mm
Loading rate
1 mm/min
Testing machine
Shimadzu AG 25TB
Load cell
Shimadzu SFL-25AG (25kN)
Disp. measurement
Machine crosshead stroke