Aerospace Rivet Joint Bearing Correction: double shear correction

d0375 t0050 to d0375 t0100

Riveted joint bearing and shear correction data from MIL-HDBK-5J Tables 8.1.2.1(a) and 8.1.2.1(b) for solid protruding-head rivets. Three sub-tables: (1) unit bearing strength (lbs at Fbr=100 ksi) indexed by rivet diameter × sheet thickness — used to compute bearing allowable as P_br = value × (Fbr/100); (2) single-shear correction factor (dimensionless, 0–1) that reduces rivet shear allowable when the thinnest sheet t/D ratio is low; (3) double-shear correction factor (dimensionless, 0–1) that reduces rivet shear allowable based on middle sheet t/D. Values tested on aluminum rivets (AD, DD, B designations). Completes the rivet joint allowable calculation pipeline alongside rivet_specifications (which provides Fsu per rivet type).