Kun P. Assessment of fatigue crack growth resistance of materials taking into account residual plastic strain

Dissertation is devoted to development of theoretical-experimental ap-proach for the estimation of residual life of structural materials taking into account the loading history. In the dissertation the generalized calculation model of cyclic deformation of the elasto-plastic material is formulated under cyclic loading for the arbitrary stress and strain state in the vinicity of fatigue macrocrack contour. Ap-proximate analytical dependences are built for the calculation of deformation pa-rameters of the model and effective SIF value. It allowed on the basis of the energy approach to develop the model of fatigue crack propagation under uniaxial cyclic loading. The algorithm of calculation of fatigue crack growth under irregular load-ing is proposed. The results of researches have been used for determination of the life time of the pipe of main oil pipeline "Kremenchuk - Kherson" under operation conditions on the aquatic passage of the Pslo river and recommendations have been passed to the enterprise "Prydniprovski main oil pipelines".