Plastic hinge

[1] In earthquake engineering plastic hinge is also a type of energy damping device allowing plastic rotation [deformation] of an otherwise rigid column connection.

In contrast to a frictionless hinge permitting free rotation, it is postulated that the plastic hinge allows large rotations to occur at constant plastic moment Mp.

Actual values of these lengths depend on cross-sections and load distributions.

[4] By inserting a plastic hinge at a plastic limit load into a statically determinate beam, a kinematic mechanism permitting an unbounded displacement of the system can be formed.

For each degree of static indeterminacy of the beam, an additional plastic hinge must be added to form a collapse mechanism.