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

ABD Composites gives engineers and students the tools to design and analyze fiber-reinforced composite laminates using Classical Lamination Theory (CLT). There are two ways to use the tool:

• Free calculator: Available directly on the website, no account needed. Great 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 is available on the website with no sign-up required. It is designed 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. All properties are in SI units (moduli in GPa, strength in MPa).

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 multiple micromechanics models: Rule of Mixtures, Halpin-Tsai, Composite Cylinder Assemblage (CCA), and Chamis. Each model has different accuracy for different property types.
• 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 automatically mirror the stacking sequence about the midplane, ensuring [B] = 0 and eliminating extension-bending coupling.
• Drag and drop to reorder plies.
• Save named laminate configurations for later comparison and analysis.

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.