|Alternative Title||A Study of Contact Behavior Considering the Substrate Compliance|
|Place of Conferral||北京|
|Keyword||基体柔度 接触行为 梁变形 失稳|
Most studies on the frictional behavior of rough surface are based on Greenwood and Williamson's model (GW model for short). The contact asperities are usually simplified to a shape such as a hemisphere or a cylinder. After such a simplification, the compliance of the asperity is often ignored. In this work, a contact model considering the compliance of the asperities was established, and the evolution of contact force and the mechanism of energy loss during contact were studied. The contribution of the substrate compliance to the contact process was discussed separately in the form of tip contact and non-tip contact.
According to the different compliance of the asperities, combined with the deformation law of the beam, we established two theoretical contact models. The main research methods and conclusions of this work are as follows:
Considering the effect of the local stress concentration in the contact area, a contact model of the tip contact with beam theory was proposed. The local deformation in the contact area was analyzed by Hertz pressure distribution, and the substrate deformation was analyzed by beam theory. The combination of the tip local deformation and substrate deformation was used as the contact response. When the asperity compliance is small, a contact model based on the Timoshenko beam model considering shear effect is established. When the asperity compliance is large, the large deflection theory of the beam was applied to the contact model. After comparison with the finite element method, the applicable scope of the theoretical solution was obtained. The study found that: 1) As the asperity compliance increases, the revolution of the contact force will change from antisymmetric to asymmetric. 2) As the asperity compliance increases, the deflection of the structure tends to deform unidirectionally and the structure becomes unstable. This instability phenomenon leads to the formation of asymmetric contact force. At the same time, the asymmetric contact force will cause energy loss in the sliding contact process.
Non-tip contact is the primary contact form for the contact of the slender rod with an obstacle. In conjunction with the principle of large deflection of the beam and the constraint condition of the contact boundary, the theoretical contact model of large deflection beam is established. Based on different motion patterns, the changes of force in the contact process and the law of energy distribution were analyzed. The difference between the contact behavior of the slender structure and the obstacle with different presupposed beam lengths was discussed. The findings of this study include the following: 1) There are two ways for the contact detachment between the slender rod and obstacles. When the predefined beam length is less than the critical beam length to maintain the structural stability, the objects are detached in the way of "pull off". When the predefined beam length is more than the critical beam length to maintain the structural stability, the objects are detached in the way of "slip off". 2) The fundamental reason for the occurrence of “slip off” is that the force acting on the slender bar exceeds the critical value of the force that maintains the stability of the structure.
|王田静. 考虑基体柔度的接触行为的研究[D]. 北京. 中国科学院大学,2019.|
|Files in This Item:|
|考虑基体柔度的接触行为的研究.pdf（3807KB）||学位论文||开放获取||CC BY-NC-SA||Application Full Text|
|Recommend this item|
|Export to Endnote|
|Similar articles in Google Scholar|
|Similar articles in Baidu academic|
|Similar articles in Bing Scholar|
Items in the repository are protected by copyright, with all rights reserved, unless otherwise indicated.