Abstract: The effects of Lorentz's force provided by unstable electromagnetic field with a mechanicai field on the stress-strain state of a nonlinear current-carrying thin plate or shell are expounded in this paper.The expressions of Lorentz's force in an electromagnetic field are derived. The stress-strain state for a ring-shape plate acted by an electromagnetic field with a mechanical field is analyzed. The optimum stress-strain state can be determined by changing the action of Lorentz's force. The present work offers design sidelines to current-carrying elements, protective components and equipment working in a strong electromagnetic field.