反平面剪切层间界面破坏的卸载行为研究

研究了由定常侧压力作用下,界面层上剪应力及位移场在卸载(反向加载)过程中的分布规律及演化规律·计算结果表明,由于裂纹前方损伤过程区的存在,卸载是非弹性的,伴随有损伤和摩擦两种耗散机制;另外,当卸载过程不能覆盖加载过程造成的损伤区时,会产生“应力锁死”现象,从而导致结构在以后的加载过程中可能产生冲击载荷·

Investigation on Unloading Behaviour of Antiplane Interface Failure

The mechanical behaviour during unloading process under the joint action of constant compression and anti-plane shear were investigated. With the so-called “shear beam model”, analytical solutions were presented for the evolution law and distributions of shear stress and displacement along the entire length of the shear beam during unloading process. The results indicate that, owing to the existing of the damage process zone ahead of the crack tip, unloading is inelastic and accompanied by friction and damage dissipation. Furthermore, “stress locking” occurs if unloading process can not cover the damage zone left by loading process, and then “shocking load” maybe occurs in following reloading process.