This tool reproduces the worked example of Art. C11.34 (diagonal semi-tension field design of a curved fuselage panel) from E. F. Bruhn, Analysis & Design of Flight Vehicle Structures, and faithfully ports the digitized design charts from the original 1998 workbook:
• Fig. C9.4 shear-buckling coefficient Ks (long curved plate)
• Fig. C9.1 compression-buckling coefficient Kc (curved plate)
• Fig. C11.19 diagonal-tension factor k = tanh[(0.5 + 300·t·d/Rh)·log₁₀(fs/fscr)] — NACA TN 2661, Fig. 13
• Fig. C11.36 web strain εE/fs = 2k/sin2α + sin2α(1−k)(1+ν) — NACA TN 2661, Fig. 31
The tension-field angle α is solved iteratively from
tan²α = (ε+εstr) / (ε+εring + (1/24)(h/R)²),
converging in a few passes. Section properties (I, stringer arms Z, effective areas) come from a separate
section analysis (Bruhn Art. A20.5) and are exposed here as editable inputs.
Engineering tool for preliminary analysis — verify against the source text and your own checks before use in certification.