74
5 Mechanical characterization on structural element level
performed in order to validate numerical models of the investigated materials. This is
described in the following.
Materials and configurations
In the framework of the bending study, different configurations of sandwich panels,
which comprise the previously investigated constituents, are studied. The tested specimens originate from six different sandwich base panels with different core heights and
face sheet lay-ups. The base panels and the tested configurations are summarized in Figure 55. Four of these panels are studied in both core orientations L and W (panels a to d),
while two panels are studied solely in W-orientation (panels e and f). Therefore, there is
a total of ten configurations. All panels were industrially manufactured in a flat press
process and comply with aviation quality standards. The nomenclature of each configuration reflects the nominal panel thickness, core orientation and face sheet layup.
7 mm
19 mm
26 mm
19 mm
26 mm
7 mm
19 mm
19 mm
10 mm
B07-W001
B07-L001
B19-W003
B19-L003
B26-W020
26 mm
B10-W010
B19-W101
B19-L101
B26-W101
B26-L101
Core Wdirection
Core Ldirection
ABS
5047-02
ABS
5047-07
ABS
5047-08
ABS
5035-A4
B19-L101
No. of ABS5047-08 plies
No. of ABS5047-07 plies
No. of ABS5047-02 plies
Core orientation
Nominal panel thickness
Test identifier (B=bending)
Specimen nomenclature
a
b
c
d
e
f
1
2
3
4
5
6
7
8
9
10
Figure 56 Summary of investigated materials and sandwich configurations
In order to support the bending study, the specimens were investigated under the microscope. For bending test specimens, the composition of the face sheets is of particular
interest, since they strongly influence the flexural panel performance. Figure 57 illustrates exemplified microscopic images of three of the investigated face sheet layups.
These images indicate that with the number of face sheet prepregs, the thickness of the
phenolic resin fillet layer tends to increase. This is due to increased excess resin of the
additional prepregs, which forms larger fillets in the co-curing bonding process. The
5 Mechanical characterization on structural element level
performed in order to validate numerical models of the investigated materials. This is
described in the following.
Materials and configurations
In the framework of the bending study, different configurations of sandwich panels,
which comprise the previously investigated constituents, are studied. The tested specimens originate from six different sandwich base panels with different core heights and
face sheet lay-ups. The base panels and the tested configurations are summarized in Figure 55. Four of these panels are studied in both core orientations L and W (panels a to d),
while two panels are studied solely in W-orientation (panels e and f). Therefore, there is
a total of ten configurations. All panels were industrially manufactured in a flat press
process and comply with aviation quality standards. The nomenclature of each configuration reflects the nominal panel thickness, core orientation and face sheet layup.
7 mm
19 mm
26 mm
19 mm
26 mm
7 mm
19 mm
19 mm
10 mm
B07-W001
B07-L001
B19-W003
B19-L003
B26-W020
26 mm
B10-W010
B19-W101
B19-L101
B26-W101
B26-L101
Core Wdirection
Core Ldirection
ABS
5047-02
ABS
5047-07
ABS
5047-08
ABS
5035-A4
B19-L101
No. of ABS5047-08 plies
No. of ABS5047-07 plies
No. of ABS5047-02 plies
Core orientation
Nominal panel thickness
Test identifier (B=bending)
Specimen nomenclature
a
b
c
d
e
f
1
2
3
4
5
6
7
8
9
10
Figure 56 Summary of investigated materials and sandwich configurations
In order to support the bending study, the specimens were investigated under the microscope. For bending test specimens, the composition of the face sheets is of particular
interest, since they strongly influence the flexural panel performance. Figure 57 illustrates exemplified microscopic images of three of the investigated face sheet layups.
These images indicate that with the number of face sheet prepregs, the thickness of the
phenolic resin fillet layer tends to increase. This is due to increased excess resin of the
additional prepregs, which forms larger fillets in the co-curing bonding process. The