Strain linearization for structural strain evaluation and maximum equivalent structural strain criterion

This paper is focused on the gross plastic deformation design check of the direct route in European standard EN 13445-3 and its applications. Six methods for the evaluation of the structural strain are introduced and compared. A generally applicable method for structural strain evaluation - the strain linearization method is presented. Refer to the maximum principle structural strain criterion used by the direct route in EN 13445-3, a maximum equivalent structural strain criterion is presented, and the criterion is more suitable for ductile materials widely used in the pressure vessels.