Study The Stress Intensity Factor Of Brazilian Circular Plate With Cracked Center Hole By Numerical Simulation

Concrete and rocks are the primary materials for civil engineering.With the development of the society,they find their increasingly extensive application.However,these fragile materials will inevitably bear fissures induced by various causes,which will cause failure of structural components under their expected strength and bring the country subsequent losses.Therefore,research on fracture toughness of fragile materials is of great significance in engineering.In this paper,the finite element software is used to simulate the static and dynamic Brazilian disk experiments with cracks in the center and the stress intensity factors are calculated using the interaction integral method and the displacement extrapolation method respectively.The above examples of the stress intensity factor handbook are used.In this method,the calculated stress intensity factor and handbook error are within3%,which ensures the accuracy of the calculation results.The paper analyzes expression form of the stress intensity factor formula of the Brazilian disk with static crack-containing center hole.Based on a large number of calculation examples,the formula is fitted of stress intensity factor with a/(R-r)of 0.1~0.8 and r/R of 0.05~0.6.The factor relation formula features high precision,simple form,and is not limited by the traditional fixed size.In the study of the static stress intensity factor generalized to the dynamic load,it was found that the increase of the pulse duration was beneficial to reduce the influence of the inertial effect of the sample.In the pulse with a duration of600 us,when the pulse duration was 1/3 of the entirety,symmetric trapezoidal velocity pulses have minimal effect on the inertial effect of the specimen.When r/R is between0.05 and 0.6 and a/(R-r)is between 0.1 and 0.6,the formula of the stress intensity factor of Brazilian disk with static unilateral cracks can be extended to dynamic load.When r/R is between 0.05 and 0.6 and a/(R-r)is between 0.1 and 0.8,the formula of the stress intensity factor of Brazilian disk with static double-sided cracks symmetrical can be extended to dynamic load.The two symmetrical cracks are beneficial to reduce the inertia effect,and the stress intensity factors of the two cracks are equal.The specimen of the double-sided cracks are more suitable for dynamic tests.