ALTERNATING STRESS 3 Characteristics of the fatigue failure: 1) work s< 2). The happening of rupture needs some numbers of cycling 3).The failure is of the brittle rupture 4) The rupture area shows obviously different zones (Smooth zone and coarse zone)3、Characteristics of the fatigue failure: 1). .  work  jx 2).The happening of rupture needs some numbers of cycling. 3).The failure is of the brittle rupture. 4).The rupture area shows obviously different zones. （Smooth zone and coarse zone）