Page 128 - 《摩擦学学报》2021年第5期

第 5 期 王大刚, 等: 考虑微动磨损的钢丝微动疲劳裂纹扩展寿命预测研究 717

表 2 不同工况下断裂疲劳钢丝椭圆状裂纹前缘尺寸、最大裂纹深度和裂纹萌生位置
Table 2 Crack front dimensions, maximum crack depths and crack initiation locations of fractured fatigue wires in
different testing conditions

Fatigue Average length of minor Average length of major Average value of maximum Range of crack
Fractured fatigue wires
cycles axis of the ellipse/μm axis of the ellipse/μm crack depth /μm initiation location, l/μm
35 000 - - - 66~90
Tensile fractured after fretting fatigue
37 000 435 603 228 64~86
with distinct fatigue cycles
40 000 452 653 287 66~91
Fretting fatigue fracture 44 904 592 1 147 526 -
Initial crack
Crack

(a) Initial crack model (b) Meshing of the crack of worn fatigue wire
Finite element simulation of fretting wear
of steel wire
No
N>N cil
Yes
Output mesh model after fretting wear
Application of boundary condition
Establishment of finite element model of Step 1: contact load of 35 N and preset tensile load of 150 N
fretting fatigue of worn steel wire Step 2: contact load of 35 N and fatigue load of 150~550 N

Finite element calculation of fretting
fatigue crack propagation Establishment of initial crack
Before load increment 1 of Step 1 : apply remeshing to
improve the mesh quality of wear scar region
Calculate the energy release rate at the
Before load increment 1 of Step 2: apply the cutting by
crack tip of fatigue wire based on
ellipsoid to creat intial crack through the wear scar
virtual crack closure technology
Calculate crack propagation depths of Setttings of crack propagation parameters
nodes at the contact region of fatigue No Set material parameters C and m
wire based on Paris formula Set mode l crack propagation
Crack propagation analysis of fatigue wire
and mesh quality optimization based on
remeshing technology

Energy release rate at
crack tip reaches
fracture toughness
Yes
Crack propagation instability indicating
fracture of fatigue wire and stop the
calculation

Fretting fatigue crack propagation
life of fatigue wire
(c) Flow chart of fretting fatigue crack propagation life prediction

Fig. 8 Finite element crack propagation model of fretting fatigue of steel wires and flow chart of fretting fatigue
crack propagation life prediction
图 8 钢丝微动疲劳裂纹扩展有限元模型及微动疲劳裂纹扩展寿命预测流程图