Overview
What is BJSFM?
The Bolted Joint Stress Field Model (BJSFM) is an analytical tool used in aerospace and structural engineering to evaluate stress distributions around bolted joints in composite laminates. It computes the boundary stresses and strains around a loaded fastener hole under combined bearing and bypass loading conditions.
BJSFM uses Classical Lamination Theory (CLT) to characterize the laminate, then applies complex variable stress functions (Lekhnitskii’s anisotropic elasticity solution) to determine the stress field around the hole. The tool supports both single-shear and double-shear joint configurations with optional countersink effects.
Bearing Loads
Cosine-distributed pressure applied to the hole boundary simulating fastener contact.
Bypass Loads
Far-field running loads (Nx, Ny, Nxy) that bypass the fastener and create additional hole-boundary stress.
Margin of Safety
Compares ply-level strains (rotated to each fiber direction) against allowable strain limits.