β Scribed by L.S. Fu
No coin nor oath required. For personal study only.
to experimental evidences that display certain correlation between ultrasonic (attenuation and velocity) factors and fracture toughness, there have been findings of certain correlation between fracture toughness and material microstructures. In an attempt to provide a mechanics view on the quantitative ultrasonic determination of fracture toughness, the author presented a literature survey. A critical discussion and summary of the survey is given. The elastodynamic fields due to the presence of a pair of inhomogeneities of plate geometry are investigated by the method of equivalent inclusions. The change of stress amplitude as the plane time-harmonic waves pass through the plates is found and the relation between the fracture toughness and the ultrasonic factors is delineated. The approach taken here does not assume the existence of a sharp crack in the material, however, a critical condition at which the ultrasonic factors are measured is implied.
π SIMILAR VOLUMES
Methods of conducting and analysing instrumented Charpy impact tests have been discussed and applied in measuring the initiation fracture toughness, K,,, of two precipitation hardened Al-alloys. For full speed impact tests a method for indirectly deriving fracture load from "system stiffness" and "
me fracture toughness of three Sic-materials was determined using specimens with straight-through notches and Chevron notches as well as specimens with Knoop-indentation cracks. The different procedures and results are compared and special effects such as crack-healing and crack surface interactions
When doing fracture toughness determinations on gray cast iron it is impossible to determine the length of the fatigue precrack from studies of the fracture surface. The reason for this is that the crack front is no well-defined line between ruptured and unruptured material but a zone of finite leng