1995 年 35 巻 4 号 p. 419-425
The fracture toughness must be evaluated under the dynamic loading condition, when the materials are used for structures tha are desired to a higher safety and must be taken into account of the effect of dynamic loading. Moreover, in order to obtain the valid Jlc value, a criterion concerning both specimen thickness B and ligament width b0 must be satisfied, which is called as "valid condition" and is described as the following equation.
B, b0 ≥ α(Jin/σfs), (α=25)
However, this equation is presented for the static loading condition and there is no assurance to be able the apply for the case of dynamic loading one. Therefore, under static and dynamic loading conditions, the effects of both B and b0 on Jin value and the flow stress σfs are investigated and the valid conditions are discussed. The results are presented that the factor α of the above equation is reduced as 20 for b0 and is increased as 28 for B under dynamic loading condition.
