X.D.1.2 “HoneycombAirbusSR” criterion

This criterion is used to calculate honeycomb core margin of safety according to the so-called “Airbus” core failure criterion that combines the two components of out-of-plane stress tensor. The margin of safety is calculated according to the following expression:

in which ${\tau }_L$ and ${\tau }_W$ are the honeycomb longitudinal and transversal shear components of Cauchy stress tensor and ${\sigma }_L$ and ${\sigma }_W$ the corresponding allowables. In fact, a strength ratio is calculated instead of a margin of safety. The relation between strength ratio, reserve factor and margin of safety is as follows:

This leads to the following expression for the strength ratio:

(The display of strength ratios instead of margins of safety allows usually a better identification of critical areas. This is true, for example, when results are saved in GMSH format.)

The arguments of the criterion are given in Table X.D.3. Compared to the “HoneycombAirbusMoS” discussed in section X.D.1.1, two new parameters are defined: “strL” and “strW” String arguments. These arguments allow specifying the Cauchy Stress Tensor components that should be considered for ${\tau }_L$ and ${\tau }_W$ respectively. Possible values are “XZ”, “ZX”, “YZ”, “ZY”, “XY” and “YX”. (This capability has been added to allow the post-processing of stress when the usual convention for honeycomb core material definition has not been followed.

The method returns an Array of 8 elements according to Table X.D.4:

• The four first elements correspond to the Result key on which the minimum margin of safety is calculated.

• Then, the two components of the out-of-plane shear stress at critical location is given.

• The critical (maximum) strength ratio is given.

• The last element of the Array is a Result object that contains the strength ratio element-per-element, node-per-node...