irrecoverable deformation meaning in English

不可回复形变
不可逆形变
塑性变形

It was shown that at all stages of unloading , interparticle sliding occurred , the number of interparticle contacts reduced and irrecoverable deformation of the microstructure occurred
通过对这些参数的研究表明：在卸载的全过程中，颗粒间相对滑移出现，相互作用的颗粒数减少，系统内部结构产生不可恢复变形。
A structured clay in this model is regarded as an assembly of lumps of different sizes , and it is assumed that the total deformation consists of 3 parts , i . e . elastic deformation of lumps , plastic deformation due to sliding between lumps and irrecoverable deformation due to crushing of lumps
这一模型把变形过程中的结构性土看作不同大小土块的集合体，总的变形将由土块的弹性变形、土块之间滑动引起的塑性变形和土块破碎引起的损伤变形三部分组成。