Optimum Design for Inserted Tooth Slips Setting Process Based on the Furrow Effect

Abstract

This work established a finite element analysis (FEA) model of an inserted tooth-type slip assembly under bear setting load and axial load, calculated the differences between the inserted teeth of the sidetracking packer slip-formed furrow shapes on the casing face, and analyzed the setting reliability of the inserted tooth slip sidetracking packer. The orthogonal optimization analysis of the structural parameters of the sidetracking packer was carried out on the basis of the furrow effect. Finally, the setting experiment was conducted with the inserted tooth slip sidetracking packer developed to verify correctness of the FEA model and the simulation results. The results show that in the FEA and calculation of the setting process of the inserted tooth-type slip, it is not only necessary to consider the furrow friction coefficient, but also the effect of the ridge on the furrow friction coefficient. The corresponding furrow friction coefficient varies according to the different furrow effects occurring on the casing surface caused by the various types of teeth inserted on the packer slips. The furrow effect is related to the sharpness of the tooth tips of the slips. The sharper the tooth tips, the more obvious the furrow effect is. Under the dual effects of the furrow effect and the adhesion effect, the carbide teeth of the slip feed into the casing wall to produce a uniform and distinct indentation on the premise of meeting the inserted tooth strength to ensure a reliable setting and hanging the inserted tooth slip sidetracking packer. The optimal combination of slip parameters was obtained by taking the optimal bite depth uniformity as the objective function: slip tooth installation spacing L = 10 mm, slip tooth installation angle α = 80°, slip tooth diameter d = 10 mm, and slip wedge angle β = 6°. The standard deviation of bite depth uniformity of the optimized slip teeth is 74.45% lower than that before optimization. The research results of this paper basically meet the requirements of engineering applications.

Experimental research on the non-uniform wear of the carbon strip of the metro pantograph

“…The furrow effect refers to the process where a raised part of a hard metal is embedded in a soft metal, pushing, and squeezing the soft metal during sliding, causing plastic flow of the soft metal and plowing out a groove. 35 The furrow effect is typical mechanical wear, which can be seen on the surface of the carbon strip when the current was small and the normal contact force was large (Figure 4). Moreover, the furrow effect only affects the surface morphology of the material and does not alter its composition.…”