ASTM D1388 — cantilever bending

Heavy-elastica boundary value problem, solved live in your browser by RK4 shooting. Nothing is precomputed.
Fabric
0.220
60 mm
Live solution
Λ = ρgL³/B
chord droop
tip deflection
At the 41.5° condition
overhang L
bending length c = L/2
G = W·c³
B (exact)
theta'' = -L (1-u) cos(theta) theta(0) = 0, theta'(1) = 0 L = rho_A g L^3 / B
Λ* = 8.006

ASTM implies exactly 8 (from c = L/2, G = W·c³). Our first-principles solution agrees to 0.08%, mesh-converged over 501→4001 nodes. The standard is confirmed, and so is the solver.

Reproduce headless:
python3 harness/14_elastica_d1388.py 0.220

Simulated using the ASTM D1388 method. Not a laboratory test — 3DS Bull is not a testing laboratory.