CRACK RESISTANCE PROPERTIES OF HIGH STRENGTH ALUMINUM ALLOYS

摘要

The principles of fracture mechanics define the critical value of as that value of crack tip driving force necessary to produce crack instability. The concept of crack instability is discussed, using the relationship of the partial derivative with respect to "a" (half crack length) and the partial derivative of R (material resistance) with respect to "a." Instability occurs when the rate of change of stress with specimen elongation is zero (da/de = 0).