The general definition of 3D warp interlock fabric can be written as:

3D warp interlock X1-X2 {N} Y1_k-Y2_k Binding Wb_k {B_k i} – Surface Ws {Ci} – Stuffer {Si} (1)

Where:

• 3D warp interlock term corresponds to the definition of a 3D warp interlock fabric architecture

• X1 represents the type of angle of binding warp yarn, O (orthogonal) or A (angle)

• X2 corresponds to the type of depth of the binding warp yarn, L (layer to layer) or T (through the thickness)

• {N} corresponds to the repetitive sequence of the different number of weft layers for each column of the 3D warp interlock fabric elementary pattern.

• Y1_k is equal to the path of the binding warp yarn of group k

• Y2_kis equal to the depth of the binding warp yarn of group k

• Binding term corresponds to binding warp yarns

• Wb_k is related to the type of weave diagram on fabric surface of

  binding warp yarns of group k

• B_k i contains the numbering of binding warp yarns of group k with inter-ply i position

• Surface term corresponds to surface weave warp yarns and disappears if surface weave warp yarns are not included

• Ws is related to the type of weave diagram of surface weave warp yarns

• Ci contains the numbering of surface weave warp yarns with inter-ply i position

• Stuffer term corresponds to stuffer warp yarns and disappears if stuffer warp yarns are not included

• Si represents the numbering of stuffer warp yarns with inter-ply i position.

If the number of weft yarns is different for each column inside the 3D warp interlock fabric architecture, then the repetitive sequence can be defined as: {N} = {n_wft (j) – n_wft (k)}, where the minus operator helps to distinguish the number of each weft yarns column and with n_wft (j)≠n_wft (k). For a constant number of weft yarns inside each column of the 3D warp interlock fabric architecture, the sequence number {N} corresponds to the positive integer value of weft yarns n_wft.

Bk i formulae can be written as: {bi – #}, with:

• bi corresponds to the different numbering value of the highest cross links of binding warp and weft yarns located at the inter ply i position of the 3D warp interlock fabric following the Wbk weave diagram.

• – operator corresponds to an inter-ply position, where the top inter-ply position 0 starts at the top of the 3D warp interlock fabric and from the left side of the formulae

• # symbol corresponds to a lack of highest cross links between binding warp and weft yarns in the inter ply position

Si formulae can be written as: {# – si}, with:

• # symbol corresponds to a lack of stuffer warp yarns in the inter ply position

• – operator corresponds to an inter-ply position, where the top inter-ply position 0 starts at the top of the 3D warp interlock fabric and from the left side of the formulae

• si corresponds to the different numbering value of stuffer warp yarns located in the inter ply i position of the 3D warp interlock fabric.

Link to Composites Part B publication : The general definition of a 3D warp interlock fabric