Issue |
JNWPU
Volume 38, Number 6, December 2020
|
|
---|---|---|
Page(s) | 1188 - 1197 | |
DOI | https://doi.org/10.1051/jnwpu/20203861188 | |
Published online | 02 February 2021 |
Evolution Behavior Analysis of Normal Contact Stiffness of Fractal Surface under Loading and Unloading
分形表面加卸载法向接触刚度演变行为分析
School of Mechanical Engineering, Northwestern Polytechnical University, Xi'an 710072, China
Received:
31
December
2019
In order to analyze the evolution of normal contact stiffness under loading and unloading, an accurate elastic-plastic contact finite element model between rigid plane and fractal surface is established by introducing the equivalent metal matrix deformation in terms of the modified Weierstrass-Mandelbrot function. The effects of the fractal dimension, scale parameter, material properties on the normal contact stiffness were discussed. A method for evaluating the normal contact stiffness was proposed to analyze the evolution of the normal contact stiffness. Numerical simulation shows that there is a positive power function relationship between the normal contact stiffness and the load of fractal surface. Under the same load, at the fractal dimensions (D) of 2.4-2.7 and scale parameters (G) of 1.36×10-13-1.36×10-10 m, the loading normal contact stiffness increases with the increasing of fractal dimension and tangent modulus, but decreases with the increasing of scale parameter. The unloading normal contact stiffness increases with the material strengthening, and the variation amplitude is positively correlated with the fractal dimension, and negatively correlated with the scale parameters and tangent modulus.
摘要
针对分形粗糙表面加卸载过程中法向接触刚度的演变问题,依据改进的Weierstrass-Mandelbrot(W-M)函数生成分形粗糙表面数字化模型,引入基于时间历程的变形修正量等效金属基体形变的影响,建立精确的刚性平面与分形表面弹塑性接触有限元模型。探讨分形维数、尺度参数、材料属性等对法向接触刚度的影响,提出加卸载时法向接触刚度评价方法并进一步分析其演变规律。数值模拟表明:分形表面法向接触刚度与载荷之间符合正相关的幂律函数关系;相同载荷下,分形维数D为2.4~2.7,尺度参数G为1.36×10-13~1.36×10-10 m时,加载时法向接触刚度随着分形维数、切线模量的增大而增大,随着尺度参数的增大而减小;卸载时法向接触刚度随着材料应变硬化而增大,变化幅度与分形维数正相关,与尺度参数和切线模量负相关。
Key words: rough surface / contact stiffness / material characteristics / fractal parameter / elastic-plastic contact
关键字 : 粗糙表面 / 接触刚度 / 材料属性 / 分形参数 / 弹塑性接触
© 2020 Journal of Northwestern Polytechnical University. All rights reserved.
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