Continuum Ligament Representation¶
The documentation describes the use of bundles of springs to represent connective tissues. This document describes the use of a continuum liagment and tendon models that may be used in the FE model.
Mesh Creation¶
Hexahedral elements are used to represent the geometry of the connective tissues, similar to Meniscus. The same approach is used to mesh the segmented surfaces, and define mesh quality.
Fiber Direction¶
The fibers are assumed to be uniformly distributed in, and perfectly bonded to the matrix. The fiber directions are defined in the image state, and run along the length of the ligament. Similar to [NBJvdG+17], the ACL and PCL are split into two fiber orientations each. These different orientations represent the amACL, plACL, alPCL, and pmPCL bundles of the ligament.
Ties¶
A nearest neighbor search is used to define the nodes in the mesh that are near the bone’s surface. These nodes are rigidly tied to the bone’s surface to represent the connective tissue’s insertion.
Interactions - contact¶
The same contact definitions that are described in the :ref:`bone, cartilage, and meniscus<InteractionsAndTiesBoneCartilageMeniscus>’ section are used to define contact for the continuum connective tissues.
These contact definitions will be used between the same connective tissues and bodies as described in Table 14
Differences from Spring Model¶
- sMCL will be one structure with two tibial insertion sites
- The ALL may not be modeled if a continuous structure cannot be segmented