Development of a Hydraulic Spring-Type, High-Speed Impact Fatigue Testing Machine and the Experimental Results

The impact-fatigue fracture of metallic materials

“…37 The ef-fects of stress concentration on fatigue strength are larger in impact fatigue than in nonimpact fatigue. 17,18 Research indicates that the impactfatigue strength of smooth specimens is lower than most materials' nonimpactfatigue strength, [3][4][5] and the difference in the endurance fatigue limit between impact and nonimpact fatigue increases with the hardness (Figure 2a). 34 But for some materials, especially low-strength alloys, such as Sn-40Pb, which has enough plasticity and a small brittle fracture trend under impact loading, the conclusion is opposite (Figure 2b).…”

“…From the studies on metallic materials, it was revealed that the impact-fatigue strength is lower than the nonimpact-fatigue strength, except for a few cases. [1][2][3][4][5] In some cases, the impact-fatigue limit is not clearly defined.…”

“…11 Compared with the nonimpact-fatigue stress pattern, the loading time of impact fatigue is very short, only about 0.1~1 percent of that in nonimpact fatigue. 3,7,12 The high loading velocity will The Impact-Fatigue Fracture of Metallic Materials Jie Yu, Peter K. Liaw, and Miinshiou Huang Figure 1. An impact-fatigue stress pattern.…”