Damage Analysis For Brittle Material Under Static Load Or Impact Load

Fracture mechanics is a subject about the failure of material and structure with crack under the load. The fracture parameters can be used to efficiently estimate the bearing capacity of the structural member with crack, and judgment the safety and reliability of the structure. Glass materials have dynamic properties which are different from ductile materials under the impact loading. The paste film can enhance the materials'impact resistance, also can effectively prevent spatter of the broken glasses after the impact.Study on the fracture process and bearing capacity of metal components by I mode fracture experiments of cast iron in this paper. Base on the impact experiment, the impact resistance and failure behavior of different types of glass specimens was analyzed. The main research work is following as(1) The three-point bending of 2 different size cast iron specimens were measured with electrical strain gauges equipment. Experimental data were analyzed and the relationship between the cohesive crack opening displacement in damaged area and loading were obtained, also the relationship between the position of cohesive crack tip and loading were obtained.(2) The three-point bending experiments of 17 cast iron specimens were tested with different prefabricated incision of wire cutting. Reference to a series of three-point bending experiments data of specimens with U notch prefabricated, the same material's test data were analyzed. The waste work were analyzed on different prefabricated incision fracture specimens. Also, the theoretical computation method were studied on the structure bearing capacity of specimens with incision.(3) Numerical simulation about I mode fracture of cast iron was carried through ANSYS finite element software, and the distribution of stress were obtained through the Post-processing. The displacement x and y's directions of some element node were figured out, and the stress intensity factor is compared with the calculated value.(4) For different types of glass specimens, the impact experiment has been done with the drop hammer and its equipment under different impacting angles. The impact process photos have been received by high-speed photography. The protect characteristic has been obtained though analysis and comparison of the data of impact process under different impacting angles and different films.