This paper purports to study the fracture criterion of a mixed-mode crack and to demonstrate that the criterion based on the CED (crack energy density) is available from completely elastic fracture to elastic-plastic fracture in a unified way. The CED in an arbitrary direction, εφ, is defined as the quantity which has the meaning of strain energy area density in the plane containing a crack front line without any restrictions on the constitutive equation. We may expect that a mixed-mode crack begins to grow in the direction φ where [formula omitted] (the mode I contribution of εφ) takes the maximum value, [formula omitted] when [formula omitted] reaches a critical value peculiar to a material (we call this criterion the [formula omitted] criterion). First, the applicability of this [formula omitted] criterion to elastic fracture is shown through the comparison between the results of the [formula omitted] criterion and the results of other criteria and experiments. Subsequently, fracture experiments of specimens of aluminum alloy with a crack inclined to the loading axis are carried out, and it is demonstrated that not only fractures with a relatively small yielding region but also fractures with a large yielding region can be explained by this [formula omitted] criterion.
|ジャーナル||Transactions of the Japan Society of Mechanical Engineers Series A|
|出版ステータス||Published - 1991|
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