MODE Ⅰ CRACK TIP FIELD WITH STRAIN GRADIENT EFFECTS

<正> A plane strain mode 1 crack tip field with strain gradient effects is investigated.A newstrain gradient theory is used.An elastic-power law hardening strain gradient material is considered and twohardening laws,i.e.a separation law and an integration law are used respectively.As for the material withthe separation law hardening,the angular distributions of stresses are consistent with the HRR field,whichdiffers from the stress results;the angular distributions of couple stresses are the same as the couple stressresults.For the material with the integration law hardening,the stress field and the couple stress field cannot exist simultaneously,which is the same as the conclusion,but for the stress dominated field,the an-gular distributions of stresses are consistent with the HRR field;for the couple stress dominated field,the an-gular distributions of couple stresses are consistent with those in Ref.However,the increase in stressesis not observed in strain gradient plasticity because the present theory is based on the rotation gradient of thedeformation only,while the crack tip field of mode 1 is dominated by the tension gradient,which will beshown in another paper.