Eventos Anais de eventos
COBEM 2023
27th International Congress of Mechanical Engineering
Permanent Regime Configurations for Orthogonal Cutting Analysis by Limit Analysis
Submission Author:
Luísa de Amorim Makhoul Gomes , RJ , Brazil
Co-Authors:
Luísa de Amorim Makhoul Gomes , Lavinia Maria Alves Borges, Fabio da Costa Figueiredo, Adriane Mougo
Presenter: Luísa de Amorim Makhoul Gomes
doi://10.26678/ABCM.COBEM2023.COB2023-1943
Abstract
This work deals with application of limit analysis theory considering frictional interfaces in the study of orthogonal cutting. Dissimilar to incremental methods, this approach is a direct method, posed as an optimization problem. In limit analysis, a permanent regime configuration is required. Regarding orthogonal cutting, this configuration is not known a priory and its determination depends on the understanding of mechanics of chip formation. However, the determination of this configuration is difficult, since it must fit the velocity field and the primary shear zone, to be analyzed using the limit analysis formulation. This cutting process is influenced by several factors, such as friction, plastic strain, and tool-chip contact length and interface, impacting the cutting dynamics, the tool life and its integrity and the surface finishing. There are many factors not fully understood, then, studying them considering the orthogonal cutting is convenient. When compared to oblique cutting, orthogonal cutting is a relative simple process. However, this process is still under study because it requires fewer parameters and allows for numerical modeling as a planar problem. Experimental procedures to study this process are limited for obtaining the shear angle in the primary shear zone and the contact between the chip and the tool in the secondary shear zone, requiring sophisticated equipment and analytical models, which are costly and time-consuming. Therefore, numerical models are more suitable for this purpose. The proposed numerical simulation is carried out by discretizing the specimen into finite elements and application of limit analysis theory. Permanent regimes configurations can be determined from proposed models found in literature, such as Merchant and Molinari. The objective is to study an orthogonal cutting model that best meets a permanent regime configuration, so that the proposed shape for the chip flow fits with the velocity field obtained by the solution of limit analysis problem. Furthermore, this paper was divided into three parts: First, the cutting forces obtained by the Merchant and Molinari models will be compared with the experimental results for two rake angle, 0 and -6°, and two contact length model found in the literature. After, the shape angle in free chip surface by Molinari model will be analyzed and compared to determined the best using the velocity fields from Molinari Model. Finally, the optimal shear angle for the Merchant model will be proposed and measured from the plastic dissipation results and, later, the cutting forces results will be compared with the theoretically shear angle obtained.
Keywords
Orthogonal cutting, numerical model, limit analysis, shear angle
