Assessment of crack evolution under multi-mode cyclic loading based on material scattered damage analysis

• Main Authors: Шульженко, Н. Г., Гонтаровский, П. П., Гармаш, Н. Г., Мележик, И. И.
• Format: Article
• Language: Russian
• Published: Інститут енергетичних машин і систем ім. А. М. Підгорного Національної академії наук України 2015
• Subjects: crack evolution; plate and cylinder; cyclic loading; scattered damage; Neuber’s principle; развитие трещины; пластина и цилиндр; циклическое нагружение; рассеянные повреждения; принцип Нейбера; УДК 539.4; развиток тріщини; пластина та циліндр; циклічне навантаження; розсіяні пошкодження
• Online Access: https://journals.uran.ua/jme/article/view/57540

Engineering method for cracks kinetic calculation of plane and axisymmetric objects under multimode cyclic load is proposed. Concept of scattered damage accumulation is used. Elastic thermostress state for all loading regimes near crack is determined by finite element method for multiple fixed crack lengths. Stress distribution for the current length rising crack is determined by quadratic interpolation. Elastoplastic deformation swings are assessed by generalized Neuber’s principle. Material damage is considered by analyzing smooth samples low cycle fatigue curves using the hypothesis of damage linear summation. Material damage is determined at points located on the way of a crack. These points located at the same sufficiently small distances (0,1¸0,2 mm). Crack jumps to the next point upon reaching the damage critical value of crack peak. Evolution of cracks in the plate and cylinder for various types of steels loaded with varying intensity zero-to-tension cycle with different temperatures is studied. The results are compared with data obtained by brittle fracture mechanics based on the equations ofParis’. Good agreement of the results shows the possibility of using the proposed approach for the assessment of fracture toughness of plane and axisymmetric structural elements.