一、机械零件上的应力大多数机械零件在工作时要承受外部负荷所造成的应力,这种应力称为机械应力或外加应力。而许多零件,除了受这种机械应力的作用外,还受有残余应力的作用。零件在成形、加工和处理过程中,各部分之间会发生不均匀塑性形变或体积变化。在这些过程结束之后,各部分之间便不可能完全协调一致,它们之间相互制约作用而产生的应力称为残余应力。有时也把残余应力叫做内应力。残余应力可分为三类。在零件的宏观尺寸范围(二维空间上线尺寸大于0.1毫米)的各部分内均匀一致,并在这些部分之间保持平衡的应力称为第一类应力。 First, the mechanical parts of the stress Most mechanical parts at work to withstand the stress caused by external loads, this stress is called mechanical stress or applied stress. And many parts, in addition to the role of mechanical stress, but also by the role of residual stress. Parts in the process of forming, processing and handling, there will be uneven between the various parts of the plastic deformation or volume changes. After these processes are completed, it is impossible for them to be fully coordinated with each other and the stress caused by their mutual restraint is called residual stress. Residual stresses are sometimes called internal stresses. Residual stress can be divided into three categories. The stress that is uniform throughout the macroscopic dimension of the part (more than 0.1 mm in line size in two dimensions) and that maintains a balance between these parts is called the first type of stress.