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Next step is to draw orphan joints/nodes to the location where the centerline of the trunnion will be welded to the elbow. In this example we click the Draw joint icon where we enter -18" in the Z direction and click the two elbow joints as shown below left to add joints where the trunnion will be welded to the elbow. Next, assign a Body constraint to each pair of joints in order to create a zero weight rigid connection. As shown below right, there needs to be a a separate Body constraint for each of these pairs of joints.
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Trunnions on elbows can reduce elbow stiffness. Users can reduce elbow flexibilities by selected elbows with a trunnion, then Design menu>Assign Design Properties for Object Type Elbow as shown below left. Users can also select elbows then assign Pipe>Property modifiers to reduce the moment of inertia and stiffness in other directions of selected elbows as shown below right.
