Finite element calculation method of contact stress between elevator safety gear brake block and guide rail
Yang WU1(),Lei XIAO2,Weiyan WANG2,Jinxin XU2,Yuan DU2,Boxin YANG1,Qi AN1,*()
1. School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai 200237, China 2. Schindler (China) Elevator Limited Company, Shanghai 201807, China
An accurate and efficient calculation method was proposed by combining the finite element method and Hertz contact formula, to study the contact stress distribution between elevator safety gear brake block and guide rail. A balance equation among wedges, rollers and guide rail was established with a nonlinear stiffness matrix, and the equation was solved by the Newton-Raphson (N-R) method combined with contact theory. The heat conduction equation was modified because of the relative motion between the wedge and the guide rail, and the transient temperature field was calculated by the Galerkin method. The accurate calculation of the contact stress distribution of the friction surface was realized through thermal-mechanical coupling iteration. Results showed that the maximum temperature of the friction surface was about 72.7 ℃ during the braking process, while the maximum contact stress was about 35 MPa. The thermal effect influence on the contact stress was greater at both ends of the friction surface than at the middle area. When the rollers’ position was moved up, both the pressure of the lower roller and the contact stress of the lower-end friction surface were reduced. When the position of the spring was moved down or the position of the friction surface was moved up, the contact stress at the lower end of the friction surface was increased, and the contact stress at the upper end of the friction surface was reduced by the upward movement of the friction surface.
Yang WU,Lei XIAO,Weiyan WANG,Jinxin XU,Yuan DU,Boxin YANG,Qi AN. Finite element calculation method of contact stress between elevator safety gear brake block and guide rail. Journal of ZheJiang University (Engineering Science), 2025, 59(1): 109-119.
Fig.5Internal energy change in control unit of guide rail during braking
Fig.6Solution process of thermodynamic coupling of safety gear
Fig.7Geometric parameters of safety gear and guide rail
材料
E/GPa
μ
α/10?6
kxy/(W·m?1·℃?1)
c/(J·kg?1·℃?1)
Q235(20 ℃)
211
0.30
10.6
51.6
450
Q235(100 ℃)
207
0.30
12.2
48.9
483
QT600(20 ℃)
169
0.27
11.1
52.2
503
QT600(100 ℃)
166
0.27
13.2
57.2
537
GCr15(20 ℃)
210
0.30
—
—
—
Tab.2Material parameters of safety gear and guide rail
Fig.8Curves of temperature and contact force
Fig.9Nephogram of temperature, displacement and stress at braking time of 80 ms
Fig.10Distribution of force and temperature at different rollers positions
Fig.11Picture of brake wedge after work
Fig.12Distribution of rollers pressure and friction surface contact stress at different spring positions
Fig.13Distribution of rollers pressure and friction surface contact stress at different friction surface positions
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