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Laminate Stacking Analyzer

Qualitatively check symmetry, balance and likely coupling from a manual ply sequence.

Qualitative CLT tool

Symmetry, balance and coupling

Instant analysis — no material properties, loads or numerical stiffness values.

Equal-thickness, one-material plies

1. Enter the stack

bottom → top
Use [0/45/-45/90]s, 0,45,-45,90 or 0/90/0/90. s mirrors the sequence.
Quick examples
Expanded sequence
xyzθ
Orientation guide
0° follows x; 90° follows y. Positive and negative angles are measured from x. z is through the thickness.

2. Read the result

qualitative only
Enter a valid stacking sequence to see the analysis.
Graphical stacking sequence
z direction
Expected mechanical behaviour
qualitative
Qualitative ABD stiffness map
Structure only — this is not a numerical stiffness calculation.
0 expectedactivecoupled
A · extension stiffness
B · extension / bending
D · bending stiffness
How to read the analysis

A laminate is symmetric when the ply sequence above the mid-plane mirrors the sequence below it. With equal ply thicknesses this normally suppresses the B matrix, so in-plane loads do not produce first-order curvature.

A balanced laminate contains matching +theta and -theta plies. This tends to cancel A16 and A26, reducing normal-load to in-plane-shear coupling.

The B matrix links membrane strain to bending curvature. A non-zero B matrix can make a laminate bend or twist under nominally in-plane loading, and is often avoided unless this coupling is intentional.

A16 and A26 are normal-shear coupling terms in the extension matrix. When present, axial or transverse loading can generate in-plane shear. Other couplings may involve bending, twisting and curvature in unsymmetric stacks.