线性强化弹塑性裂纹尖端韧带线场

LIGAMENT FIELDS AHEAD OF A CRACK TIP UNDER PIECE-WISE ELASTIC-PLASTIC MODEL

计及弹性应变 ,引入一代表裂尖区各点弹性变形、塑性变形比例的参量νep,得到平面应变下Ⅰ型裂纹的线性强化弹塑性韧带近似解 ,并导出其应力、应变以及能量密度的表达式。νep作为约束参数进入弹塑性裂纹尖端场 ,其值的变化可引起裂尖能量密度场的明显变化。

A constraint variable of ν ep that represents the ratio of elastic to plastic deformation is introduced. An approximate ligament field of mode Ⅰ plane-strain crack problems under Piece-wise elastic-plastic model is obtained. The investigation emphasis on energy densities other than stresses. It is concluded that elastic energy is still important in elastic-plastic fracture process. There is a non-uniform distribution of the energy density around a crack tip. The decreasing of constraint variable ν ep leads the near tip pattern of energy distributions gradually become uniform and so leads high critical values of J integral.