144
7 Virtual testing approach for sandwich panel joints
Figure 113 Virtual test model for partially potted insert under out-of-plane tension [See18]
The results of the simulation model are displayed in Figure 114. The implemented model
proves to accurately represent the test results in terms of both, force-displacement relationship and visual damage mechanisms. In terms of strength and stiffness the model
results align with the average test results with only about 2% deviation. The post failure
behavior is not matched with the same accuracy. However, this is not the requirement
for the model. Regarding the damage mechanisms, it can be summarized that the model
reproduces not only the two relevant mechanical effects in the correct order, but also
the remaining damage mechanisms such as face sheet damage and debonding of face
and core (Figure 114, left). However, this debonding is represented in the model as tensile failure of the core. Therefore, it can be concluded that the implemented partially
potted model agrees well with the reference test and the given example validates the
approach.
Insert
C3D8R | Elastic
0.5mm elemsize
Face-core bond
Tied contact
Penalty contact
y
x
z
Honeycomb
S4R | Orth. plastic
0.4/1.5mm elemsize
Fixture
C3D8R | Isotr. elastic
5mm elemsize
Potting
C3D10M | Isotr. bi-plastic
0.8mm elemsize
S4R | Orth. fabric (VUMAT)
0.4-2mm elemsize
Tx,Ty,Tz = 0
Rx,Ry,Rz = 0
Tz = v
Tx,Ty = 0
Potting-core bond
Tied contact
Face
Fixture to Face