Panel Metallic Failure

The Panel_metallic configuration is shipped with a DLL method called Panel_FailureMode. It computes four possible failure modes for a metallic panel. The method requires shell element forces to be available in the result file. It assumes a valid panel with constant thickness and retrieves thickness information from its structural property. Panel thickness is used to recompute element stress XX, YY, XY. Similarly, the structural property’s material is used to extract tensile/compressive and shear allowable. The method evaluates Margin of Safety as MS= Allowable/Stress -1 for the three directions. For directions one and two (XX and YY), depending on the stress state, either tensile or compressive allowable is used. For shear (XY) absolute stress value is considered in the margin of safety formula.

A fourth failure mode is computed as shear buckling failure of curved panel. In the latter, the highest shear force seen by all elements in the design point is considered. Shear buckling is a ratio of stress with Fscrit = π MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaeqiWdahaaa@37B3@ 2KcE/(12*(1- v MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamODaaaa@36F1@ 2)*(t/b)2 where Kc=Rs+0.2*W2/(R*T).

Rs is available as structural property metadata Radius_shear_constant and the default is 5.35.



Figure 1. Panel Metallic Failure method