5.1 Panel flexure
81
a)
b)
c)
Figure 61 Implemented FE-models for virtual bending tests; a) Model description in
case of four-point bending; b) Three-point bending model; c) Four-point bending with
loading plates
The element size of the 3D-continuum core is 1 mm in the vicinity of load and support
cylinders. This element size indicates converged results regarding local core indentation.
In the far field the element size is defined so that there are five elements along the core
height in order to ensure a good approximation of the shear stress. Therefore, the far
field element size is variable throughout the implemented models depending on the core
thickness. The contact between locally refined and coarse far field mesh is implemented
as tied contact. This 3D-continuum core modelling approach is illustrated in Appendix
B2. Regardless the core modelling approach, the bond between core and face sheets is
Cylinders
Face sheets
C3D8R
Rigid body
S4R
Orth. fabric
Face-core bond
Tied contact
Cylinder-face
Penalty contact
Friction 0.2
Honeycomb
S4R/C3D8R
Orth. plastic
y
x
z
Tz = v
Tx,Ty = 0
Rx,Ry,Rz = 0
Tx,Ty,Tz = 0
Rx,Ry,Rz = 0