If link properties were defined using Fixed DOFs, then the The forces reported for the fixed DOFs would be zero if link properties were defined using Fixed DOFs, because using fixed DOF will not allow any relative displacement or rotation between the link end joints and thus the relative displacement or rotation would be zero and then the link force calculated as F = ku would be also reported as zero. If you need to retrieve forces from link elements, then high stiffness instead of fixed property should be specified for the DOFs in question.
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