基于微观划痕的疲劳强度预测

对微观划痕进行截面观察，确定截面具有三角形的几何特征.提出了适用于确定微观划痕投影面积的两原则:方向无关和长度无关.据此，建立了微观划痕疲劳损伤参数area_Δ，定义为多条微观划痕中截面三角形面积平方根的最大值.最后，结合area_Δ和Murakami理论，提出了基于微观划痕的疲劳强度模型.利用高强度钢FV520B-I疲劳强度实验和Ti-6Al-4V钛合金现有文献数据对模型进行验证，结果表明该模型具有一定的疲劳强度预测精度优势.

Fatigue Strength Prediction Based on Micro Scratches

Based on the observation of micro scratches， the cross section of the scratches has the geometric characteristics of triangle. Two principles which are direction-independent and length-independent were proposed for determining the projection area of micro scratches. Accordingly， a new parameter area_Δ was defined as the maximum square root of triangle area of micro scratch section， to describe fatigue damage quantitatively caused by the micro scratches. A modified fatigue strength model with the consideration of micro scratches was established by using the Murakami model and the term of area_Δ.The model was validated by the fatigue strength experiment of high strength steel FV520B-I and the existing data of Ti-6Al-4V titanium alloy from literature. The results showed that the model had a certain advantage of prediction accuracy in fatigue strength prediction.