Brittle fracture strength on designing and loading

Brittle fracture strength of design having notches varies complexly with the relative locational relationship between the main load applied and the introduced crack in a specimen. It also varies with the design factor of the length to width ratio of a specimen. Experimental results in unsaturated polyester resins predict that the brittle fracture strength of edge notch or center notch specimens fractured in an outside loading method increases with decreasing the length to width ratio of a specimen and that the strength in an inside loading method decreases with decreasing the ratio. Results of photoelastic study and fracture path analysis give good evidence to the conclusion elucidated above. Practical application tests were made on quenched S50C martensitic steel specimens and the relationships were examined.