General criterions for determination of the local stress state at the crack tip of the material under different types of loading conditions such as: i) static, ii) impact, iii) high-speed impulse, iv) impact-cyclic, v) cyclic are proposed. They are the ratio of the maximum depth plastic zone to the specimen thickness (h~,*It) and the ratio of the diffraction line width obtained from the fracture surface to the diffraction line width obtained from the unstrained metal (P/fio)• The plane strain deformation condition under static and cyclic loading conditions may be defined more precisely using by above criterions. X-ray techniques for determination: i) material fracture toughness of the failed constfuction, ii) critical fatigue crack length /* and /f, iii) stress of the loading cycle, iv) [oad ratio R, v) track growth speed are presented. If the fracture surface was completely damagedby corrosion or mechanical affect, X-ray techniques may be used for identification of the type of the fracture surface. If the plane strain deformation (PD) and the plane stress state (PS) at the crack tip are two extreme stress states then under normal loading conditions there will be a transition state between the above stress states. Therefore it is necessary to provide a criteria for the quantitative evaluation of the local stress state in the transition range from PD to PS. It must be general criteria for different types of loading conditions. It is also necessary to indicate the acceptable intervals where the stress state may be treated as either plane stress or plane strain deformation. Theknown criteria detailed in paperl'2) are not always physically substantiated, and do not cover all types of loading conditions. It was shown in the first part of the paper that the ratio of the maximum depth of the plastic zone under the fracture surface to the specimen thickness (h~**/t) can serve as such a criterion for the evaluation of the local stress state at the crack tip under different types of loading conditions.
