Damage States in Woven Composites

There are nine distinct damage states for woven composite materials.

In woven composites, there are five fundamental constituent materials: the matrix constituent of the fill tows, the fiber constituent of the fill tows, the matrix constituent of the warp tows, the fiber constituent of the warp tows, and the matrix constituent comprising the pure matrix pockets. Utilizing a failed or unfailed status of these five constituents, there are a total of nine distinct damage states for the woven composite material.

Damage State 1: All constituents unfailed

Damage State 2: Failed matrix constituent in the fill tow

Damage State 3: Failed matrix constituent in the warp tow

Damage State 4: Failed matrix constituents in the fill and warp tows

Damage State 5: Failed fiber and matrix constituents in the fill tow

Damage State 6: Failed fiber and matrix constituents in the warp tow

Damage State 7: Failed fiber and matrix constituents in the fill tow, failed matrix in the warp tow

Damage State 8: Failed fiber and matrix constituents in the warp tow, failed matrix in the fill tow

Damage State 9: Failed fiber and matrix constituents in the warp and fill tows

Note: Although the current implementation of Helius PFA does not explicitly apply a failure criterion to the matrix constituent that comprises the pure matrix pockets, the matrix pocket is also considered failed for Damage States 4-9.

As was the case for unidirectional composites, the MCT decomposition depends directly on the stiffness properties of the various constituents. Each composite damage state contains a unique combination of failed and unfailed constituents. Therefore, the MCT decomposition changes as the composite material transitions from one damage state to another damage state.