The nano-metric cutting process of single-crystal SiO2 was studied using molecular dynamics simulation, where the effects of anisotropy on material removal and surface integrity were analyzed. The typical crystal directions on different crystal planes of SiO2 were selected as cutting directions. The results show that the chip formation, temperature distribution in the machined area, cutting force, phase transformation and damage layer thickness vary according to the cutting direction. The crystal orientation of (110) [00−1] exhibits a large range of damage expansion while (110) [1−10] exhibits the smallest range. In addition, the radial distribution function results show that SiO2 workpieces cut in different directions vary in crystal phase type and content to some degree, while a new phase is produced in the cutting direction of (111) [−101]. Therefore, the anisotropy of the selection of crystal planes and crystal directions is of great significance for the nano-metric cutting of SiO2 to obtain quality machined surfaces of SiO2.

No abstract

Hotspots in traction motors of electric vehicles are normally considered to locate in end windings due to the loose packaging and no access to iron cores for heat dissipation. To ensure safety, end winding temperatures are typically monitored by thermocouples in thermal management systems for real‐time cooling control. However, the authors’ study finds that slot winding temperatures will exceed end winding temperatures under high‐speed operations due to the much higher additional loss caused by the alternating flux. Hence, the thermocouple would underestimate the actual peak temperature in electric machines, causing insufficient cooling and potential damage to insulations. For cost savings, additional thermocouples monitoring slot winding temperatures are usually not equipped in the automotive industry. To calibrate the peak temperature of windings, this study proposes an innovative approach based on the thermo‐magnetic model of the traction motor, which provides the estimated slot winding temperatures only using the end winding sensors. As a result, the proposed method can provide much accurate peak temperatures for the thermal management system. Experimental tests validate the performance of the proposed method in improving the accuracy of hotspot monitoring.