bolt-pattern-elastic-method 1.0.0

Bolt pattern force distribution analysis

Implements the methodology from NASA RP-1228.

Given a bolt pattern (positions + areas) and applied loads at arbitrary locations, this module computes the axial and shear force on each bolt.

Outputs verified against the calulator here: https://mechanicalc.com/reference/bolt-pattern-force-distribution

Example usage:

if name == "main": import os import bolt_pattern_elastic_method

HERE = os.path.dirname(os.path.abspath(__file__))

positions_1 = [(-3.5, 15), (3.5, 15), (-3.5, -15), (3.5, -15)
               , (10, -15), (18.82, -12.14), (24.27, -4.635)
               , (24.27, 4.635), (18.82, 12.14), (10, 15)
               , (-10, 15), (-18.82, 12.14), (-24.27, 4.635)
               , (-24.27, -4.635), (-18.82, -12.14), (-10, -15)] #[x,y]

# ------------------------------------------------------------------
# Example 1: 4-bolt rectangular pattern, in-plane eccentric shear
# A 1000 N force applied in X at (y=5) – creates torsion about Z
# ------------------------------------------------------------------
print("\nEXAMPLE 1 – General 3-D loading")
save_path="bolt_pattern_ex1.png"
analysis_1 = BoltPatternAnalysis(
    bolts=[Bolt(x, y) for (x, y) in positions_1],
    loads=[AppliedLoad(Fx=1500.0, Fy=500.0, Fz=5000.0, z=15.0),
           AppliedLoad(Mz=1000.0)],
)
results_1 = analysis_1.solve()
print_results(results_1, analysis_1)
plot_bolt_pattern_3d(
    analysis_1, results_1,
    title="Example 1 - General 3-D loading",
    show=False,
    save_path=os.path.join(HERE, "save_path"),
)
print(f"  → saved {save_path}")


# ------------------------------------------------------------------
# Example 2: general 3-D loading using the convenience function
# ------------------------------------------------------------------
print("\nEXAMPLE 2 - General 3-D loading (convenience function)")
analysis_2 = BoltPatternAnalysis(
    bolts=[Bolt(x, y, label=lbl) for (x, y), lbl in zip(
        [(-3, -3), (3, -3), (3, 3), (-3, 3)], ["TL", "TR", "BR", "BL"]
    )],
    loads=[AppliedLoad(Fx=200, Fy=-150, Fz=300,
                       Mx=500, My=-400, Mz=1000,
                       x=1.0, y=2.0, z=50.0)],
)
results_2 = analysis_2.solve()
print_results(results_2, analysis_2)
plot_bolt_pattern_3d(
    analysis_2, results_2,
    title="Example 2 - General 3-D Loading",
    show=False,
    save_path=os.path.join(HERE, "bolt_pattern_ex2.png"),
)
print("  → saved bolt_pattern_ex2.png")