CRACK RESISTANCE OF BABBIT B83

Babbit 83 crack resistance test in accordance with SSR 25-506-85 was carried out. By finite element method there were defined values of stress intensity factors in flat samples with a grown crack. The fracture viscosity characteristics of babbit are obtained. On the basis of a macro-fractographic analysis of wear fractures of a babbit sample and a finite element procedure for the definition of values of stress intensity factors the cha-racteristics of cyclic crack resistance are obtained. It is shown that a final fracture is realized at 3 МПа , and a transition from an elastic stage to the stage elastoplastic development of a crack is realized at 2,0…2,8 МПа .

Study on Behaviors of Jute Fiber Reinforced Cement Based Materials

In this study, jute fibers were added into cement based materials to improve their compressive strength, flexural strength and early-age crack resistance. Results showed that the compressive and flexural strength of the fiber reinforced concrete were significantly enhanced with 30mm length jute fiber at the mixing amount of 0.5-0.6 kg•m-3. For early-age crack resistance test, the effective mixing amount would be 0.9 kg•m-3 and the fiber should be shorter than 20mm.

Crack Resistance and Structural Analysis on Thermit Welding

War-broken parts can be repaired quickly without electricity and gas in the wild by use of the thermit welding technology, so it is of great significance to study on welded quality of thermit welding parts for its military application. As the crack resistance of welded parts is an important target to estimate the welded performance, crack resistance test and microstructure analysis have been conducted on test specimens made of Q235 welded parts. Results showed that as the crack ratio was less than 20% in the Y-groove crack test, the crack propagation would not occur in the practical welding structure and that the crack resistance of welded joints could meet the welded demand.