Laminate Module

Access the laminate analysis windows.

The Laminate drop-down menu provides access to four different laminate analysis windows. Below is a brief description of the laminate analysis features accessible from the Laminate drop-down menu. A detailed description of these features and their use is given in the pages that follow.

1. Laminate Properties - This window includes several basic functions to determine laminate properties:
   • Q-bars - For each ply in a laminate, Helius Composite computes the plane stress (or reduced) stiffness matrix expressed in the global coordinate system.
   • [ABD], [ABD] Inverse - Classical Laminate Theory (CLT) is used to compute the 6x6 laminate stiffness matrix (expressed in terms of the 3x3 [A], [B], and [D] matrices), or the 6x6 laminate compliance matrix (expressed in terms of the 3x3 [A] Inverse, [B] Inverse, and [D] Inverse matrices).

     [A] matrix

     Defines the in-plane extensional and shearing stiffness of the laminate.

     [B] matrix

     Defines the coupling between the in-plane stiffness of the laminate and the bending stiffness of the laminate.

     [D] matrix

     Defines the bending stiffness of the laminate.

   • Laminate Engineering Properties - Helius Composite computes a set of 2-D and 3-D engineering properties for a homogeneous material that has the same effective properties as the laminate. These 2-D and 3-D engineering properties are the "smeared" properties of the laminate.
     Note: The values computed within this tool are for symmetric and balanced laminates. Use caution when using these values for un-symmetric and/or un-balanced laminates.
2. Stress-Strain and Strength Analysis - This window includes several options for determining the stress, strain, and strength of a laminate:
   • Global/Local Stress/Strain - Compute the stress and strain state in each ply of a laminate subjected to a user-specified set of in-plane and bending loads. The computed ply stresses and strains can be expressed in the global coordinate system or the principal material coordinate system of each individual ply.
   • Mid-Plane Strains/Curvatures - Compute the laminate's mid-plane strains and mid-plane curvatures when subjected to a set of user-specified in-plane and bending loads.
   • First Ply Failure - When a laminate is subjected to a user-specified set of in-plane and bending loads, Helius Composite identifies the first ply that fails and identifies the type of failure (failure mode) exhibited by the ply.
   • Progressive Failure - Compute the progressive failure response of the laminate due to a user-specified set of in-plane and bending loads. Helius Composite identifies the sequence of individual plies that fail as the laminate is progressively loaded. When a particular ply fails, the stiffness of the failed ply is drastically reduced to simulate the consequence of its failure. Degradation of the failed ply's properties causes additional load to be distributed among the remaining unfailed plies as loading continues. Depending upon the particular laminate being analyzed and the set of loads applied to the laminate, the ply-by-ply progressive failure process can be sudden and catastrophic or very gradual and non-catastrophic.
3. First Ply Failure Survey - Determine the laminate's axial tensile strength, axial compressive strength, transverse tensile strength, transverse compressive strength, and in-plane shear strengths based on first ply failure.
4. Failure Envelope - Compute a failure envelope for a laminate subjected to a pair of user-specified in-plane loads. The failure envelope concisely shows all possible combinations of the two selected in-plane loads that cause laminate failure.

Upon selecting one of these four options from the Laminate drop-down menu, a window appears with the associated analysis options separated into tabs, as shown above. Each of the four windows begins with the same Laminate tab where you define the laminate to be used in the analysis. Therefore, before providing a detailed description of the use of the four laminate analysis options, the next page provides a detailed description of this common Laminate tab.