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Classical Laminate Theory (CLT)

Calculate laminate ABD stiffness, in-plane engineering constants and the response to in-plane loads and moments.

Plane-stress laminate model

Laminate stiffness and load response

All inputs are entered manually. The first ply is the bottom of the laminate (-z).

Linear elastic CLT - preliminary engineering use
mm

1. Orthotropic ply properties

Use reduced plane-stress lamina properties in the material 1-2 axes. E1/E2/G12 follow the selected unit system; nu12 is dimensionless.

2. Ply stack: bottom to top

PlyAngle [deg]Thickness [mm]
1
2
3
4

3. Applied resultants (optional)

Leave loads at zero to calculate stiffness only. Moments are moments per unit width.

Output

Enter ply material properties and the laminate stack, then calculate ABD stiffness.
Total thickness: ---
Ex [GPa]
-
Ey [GPa]
-
Gxy [GPa]
-
nu_xy [-]
-
nu_yx [-]
-

A [N/mm]
B [N]
D [N mm]

Mid-plane strains [microstrain]
Curvatures [1/m]

CLT manual of use

1Define the lamina

Enter E1, E2 and G12 in GPa and nu12 without units. Values must represent the same orthotropic UD lamina under plane stress.

2Build the laminate

Add each ply manually from the bottom surface to the top. Enter fibre angle in degrees and individual ply thickness in the selected unit system.

3Read the outputs

A, B and D describe extension, extension-bending coupling and bending. Enter N/M resultants only when you need mid-plane strain and curvature.

Scope: linear elastic, thin laminate, plane-stress CLT. It does not predict transverse shear, free-edge/interlaminar stress, damage, buckling or failure. Validate design values with the applicable test and analysis method.