Analysis of Curved Plates

This page provides the chapters on the analysis of curved plates from the "Stress Analysis Manual," Air Force Flight Dynamics Laboratory, October 1986.

Other related chapters from the Air Force "Stress Analysis Manual" can be seen to the right.

Nomenclature

a = plate length
b = plate width
C = compressive buckling coefficient for curved plates
E = modulus of elasticity
Es = secant modulus
Et = tangent modulus
F0.7F0.85 = secant yield stress at 0.7E and 0.85E
Fcr = critical normal stress
Fcrs = critical shear stress
kc = compressive buckling coefficient
r = radius of curvature
t = thickness
Zb = length range parameter b2(1 - νe2)1/2/ rt
η = plasticity reduction factor
ν = inelastic Poisson's ratio
νe = elastic Poisson's ratio

6.6 Axial Compression of Curved Plates

The radius of curvature of curved plates determines the method to be used to analyze their buckling stress. For large curvature (b2/ rt < 1), they may be analyzed as flat plates by using the relations in Section 6.3. For elastic stresses in the transition length and width ranges, Figure 6-31 may be used to find the buckling coefficient for use in Equation (6-31).

$$ F_{cr} = { k_c ~\pi^2 E \over 12 (1 - \nu_2^2) } \left({ t \over b }\right)^2 $$
(6-31)

Buckling Coefficient Grouped According to r/t Values for Curved Plates

For sharply curved plates, (b2/ rt > 100), Equations (6-32) and (6-33) can be used.

$$ F_{cr} = \eta ~C ~E \left({ t \over r }\right) $$
(6-32)
$$ \eta = {E_s \over E} {E_t \over E_s} { (1 - \nu_e^2) \over (1 - \nu^2) } $$
(6-33)

Figure 6-32 gives values of C in terms of r/t. Figure 6-33 gives η in a nondimensional form. Here the quantity ϵcr = Ct/r.

Modified Classical Buckling Coefficient as a Function of r/t for Axially Compressed Cylindrical Plates

Nondimensional Buckling Chart for Axially Compressed Curved Plate




6.7 Shear Loading of Curved Plates

Large radius curved plates (b2/ rt < 1) loaded in shear may be analyzed as flat plates by the methods of Section 6.5. For transition length plates (1 < b2/ rt < 30), Figure 6-34 can be used to find ks for use in Equation (6-34).

$$ F_{crs} = { k_s ~\pi^2 E \over 12 (1 - \nu_e^2) } \left({t \over b}\right)^2 $$
(6-34)

For (b2/ rt > 30), Equation (6-35) may be used.

$$ F_{crs} = 0.37 ~(Z_b)^{1/2} (F_{crs})_{\text{flat plate}} $$
(6-35)

Curved plates under shear loading with stiffeners can be analyzed by using Figure 6-35 for the value of the buckling coefficient ks. Both axial stiffeners and circumferential stiffeners are treated.


Shear Buckling Coefficients for Various Curved Plates

Shear Buckling Coefficients for Various Curved Plates

Shear Buckling Coefficients for Various Curved Plates

Shear Buckling Coefficients for Various Curved Plates

Shear-Buckling Coefficients for Simply Supported Curved Plates with Center Stiffener

Shear-Buckling Coefficients for Simply Supported Curved Plates with Center Stiffener

Shear-Buckling Coefficients for Simply Supported Curved Plates with Center Stiffener

Shear-Buckling Coefficients for Simply Supported Curved Plates with Center Stiffener