Getting Started

How to use ABD Composites: from defining materials through micromechanics to a full CLT laminate analysis, plus the theory behind every tool.

Overview

Engineers and students use ABD Composites to design and analyze fiber-reinforced composite laminates using Classical Lamination Theory (CLT). There are two ways to use it:

• Free calculator: Available on the website, no account needed. Use it for quick calculations and exploring laminate behavior.
• Full dashboard: Requires a free account. Lets you save materials, lamina, and laminate configurations, and run more detailed analyses.

The general workflow in the dashboard follows these steps:

Using the Free Calculator

The free CLT calculator needs no sign-up. It is for quick exploration of how layup parameters affect laminate stiffness.

• A default material is pre-loaded (typical CFRP ply properties).
• Enter custom ply properties (E₁, E₂, G₁₂, ν₁₂) if needed.
• Set the number of plies, their angles, and thickness.
• Enable the symmetric layup option to automatically mirror the stacking sequence.
• The ABD matrix and engineering constants (Ex, Ey, Gxy, νxy) update in real time as you type.

Dashboard: Material Management

The Materials section lets you build a library of material properties. Three kinds are entered directly:

• Fiber materials: Longitudinal and transverse moduli (E₁f, E₂f), shear modulus (G₁₂f), Poisson's ratio, and density. Example: T300 carbon fiber, E-glass.
• Matrix materials: Young's modulus (Em), Poisson's ratio (νm), and density. Example: standard aerospace epoxy.
• Core materials: Shear modulus (G_c), through-thickness compressive modulus (E_c), density, and optionally shear and compressive strength (F_su, F_cu), for use in the sandwich panel tool. Example: Nomex honeycomb, Rohacell, Divinycell, balsa. Each core can carry a source citation so a handbook or datasheet value stays traceable.

Two more kinds are built rather than typed in: laminae, which the UD lamina and fabric builders produce from a fiber and a matrix, and laminates, which the laminate builder assembles from laminae. Both are saved to the same library and reused by every analysis tool.

A standard library of commonly used materials (T300, E-glass, and standard epoxies) is pre-loaded into every account. You can copy and modify these, or add your own from scratch. Properties display in your unit preference: the SI, Metric and Imperial presets fill in a sensible unit per quantity, so Imperial shows moduli in Msi and strengths in ksi. The Units tab on the account page lets you change the unit for any individual quantity (say Msi moduli with mm thicknesses) as your own Custom set. Values are stored unit-independent, so switching presets never changes your data.

Dashboard: Micromechanics (UD Lamina Builder)

The Micromechanics section predicts unidirectional (UD) ply properties from fiber and matrix constituent data. This is useful when you have material data sheets for the constituents but not measured lamina properties.

• Select a fiber and a matrix material from your library.
• Set the fiber volume fraction (Vf), typically 0.55-0.65 for aerospace laminates.
• Choose from six micromechanics models: Rule of Mixtures, Halpin-Tsai, Composite Cylinder Assemblage (CCA), Chamis, Hopkins-Chamis, and Puck. Which model is most accurate depends on the property.
• Save the predicted ply properties as a new lamina for use in the laminate builder.

Dashboard: Laminate Builder

The Laminate Builder lets you define stacking sequences from your saved lamina.

• Select a lamina from your library for each ply.
• Set the orientation angle (in degrees) and thickness (in mm) for each ply.
• Use the symmetric layup option to mirror the stacking sequence about the midplane, which gives [B] = 0 and removes extension-bending coupling.
• Drag and drop to reorder plies.
• Save named laminate configurations for later comparison and analysis.

Layup options

Everything you set once and then leave alone sits in a collapsible Layup options panel, so the ply table keeps the space. The panel header carries a chip for each option that is currently active, so nothing is hidden while its effect is on screen.

• 1 thickness and 1 lamina: type the value once at the first ply and every ply below inherits it.
• Rotate stack: add one offset to every ply angle at once, with -45, +45 and +90 presets, a slider and a typed value. Angles are wrapped back into -90 to 90, and one button clears the rotation.
• Reverse stack: turn the laminate over. In-plane and bending stiffness are unchanged and every coupling (B) term changes sign.
• Paste, Copy and Clear: move a layup in or out as JSON, or start again.

Rotate and Reverse edit the ply angles and the ply order themselves rather than storing a transform, so a saved laminate always holds exactly what the table shows.

Dashboard: Laminate Analysis

The Analysis page runs a full CLT calculation on your laminate and displays:

• ABD matrix: Full 6×6 constitutive matrix (extensional, coupling, and bending stiffness submatrices)
• Compliance matrix: Inverse of the ABD matrix. Relates strains and curvatures to applied loads
• Engineering constants: Effective Ex, Ey, Gxy, νxy derived from the compliance matrix

The theory documentation

Classical Lamination Theory, from fibre and resin properties through to a structural check, written to be read in order. Each page explains the concepts and gives the governing equations without turning into a full derivation. Working on something specific? Jump straight to it.