CRACK TIP FIELDS UNDER NON-STEADY CREEP CONDITIONS—II. ESTIMATES OF ASSOCIATED CRACK GROWTH

Abstract— In a companion paper, estimation formulae have been presented for describing the amplitude of the crack-tip fields under load and displacement controlled boundary conditions. In this paper the associated amounts of creep crack growth are derived. For constant loading, it is shown that the transition period before the attainment of steady creep conditions can be neglected provided the accumulated creep strain at a reference stress exceeds the elastic strain at the same stress. Under constant displacement conditions, it is shown that the amount of creep crack growth is limited and can be predicted from the extent of load relaxation due to creep. This result is confirmed by comparison with experimental data.