I am creating a 3D model of the shoulder in Abaqus, including soft tissues such as the glenohumeral ligaments, to study various factors that could lead to anterior joint instability. I am using ABAQUS with implicit dynamic simulations, which allows me to simplify the humerus as a rigid body. The ligaments are modeled as membrane-type elements, but they need to be connected to the humerus at their insertion points using some kind of tie constraint.

I tried using the tie constraint, but it causes very high deformations in the ligaments, especially near their insertion points on the humerus. This issue does not occur on the scapular side, which is not modeled as a rigid body (though here I also use a tie). I believe this may be due to the fact that membrane elements have only three degrees of freedom (DOFs).

How can I resolve this issue and properly “connect” the humerus and the ligaments?