Due to the high temperature toughness and low thermal conductivity of 2.25Cr1Mo0.25V material, the rake face of the tool can easily wear out during the cutting process, which reduces the service life of the tool. In this paper, by analyzing the contact behavior, heat exchange conditions and tool wear mechanism during the cutting process, a 3 D finite element simulation model of tool wear in accordance with the actual cutting process is established. Combined with the cutting wear experiment, the validity of the model is verified. The influence of cutting speed, cutting depth, feed rate and the interaction between them on rake face wear was studied by designing a simulation scheme. The simulation results show that: With the increase of cutting speed and feed rate, the wear depth of the tool's rake face gradually increase, but for cutting depth, the depth of wear gradually decreases. The interaction of cutting speed and feed rate has a significant influence on the rake face wear, the interaction between cutting speed and feed rate, and the interaction between feed rate and cutting depth are not significant. The research results provide a theoretical basis for improving the service life of the tool and provide technical guidance for the selection of cutting parameters in the actual production.
Entropy-regulated electrolytes exhibit improved performance exceeding traditional liquid systems. Despite their potential merits, the impacts of entropy on thermodynamics and kinetic properties of the electrolyte have remained elusive. A specially designed entropy-regulated Zn-salt electrolyte (ERE) with multiple halogen anions (Cl−, Br−, and I−) is proposed here to discuss the correlation between locally excess entropy and diffusion properties. Owing to the higher pair-correlated entropy of the ERE compared to single-anion systems, it can greatly facilitate the Zn2+ transport and impede the ion aggravation, thus elevating the stability of Zn anodes. The Zn2+ transference number of ERE reaches a high value of 0.822, contributing to much improved cycling life and Coulombic efficiency of plating/stripping processes of Zn anodes. Moreover, the high-entropy identity results in better anti-freezing ability of the electrolyte system, therefore ensuring the ERE stably operating even under a low temperature of −40 °C. This work can provide valuable directions for designing high-performance electrolytes for various batteries by modulating specific excess entropy.
As the most commonly used method in speed governor for marine diesel engine, PID control method is not very effective for nonlinear systems with big variation of parameters.To improve the dynamic precision of diesel speed governor, a fuzzy PID hybrid controller of parameter self-adjusting is put forward in this paper.The mathematical model of diesel engine and its speed regulation system are presented and computer simulation is conducted in Matlab software.Simulation results verify that the proposed method improves the control accuracy of speed of diesel engine compared with conventional PID controller.
The bond breakage on the rake face of cemented carbide inserts has a significant impact on the life of the insert. The problem of cemented carbide insert bonding damage is analyzed, and the main failure mode of cemented carbide insert is brittle fracture. Based on the extended finite element method (XFEM) and cohesive technology, and according to the stress state of cemented carbide insert in different cutting states and the position of adhesion layer, the actual boundary conditions are set in ABAQUS simulation environment. The three-dimensional macroscopic simulation model with crack structure and load-bearing capacity that meets the actual working conditions is established, and the influence of no cracks, single cracks at different angles, multiple cracks, and load on the peeling of the adhesion layer are analyzed. Regardless of whether it is in the state of no pre-crack or multiple cracks, the rake face is damaged when the adhesive layer is subjected to a shear load parallel to the rake face, which is similar to the experimental results. while in the single crack state, the position, angle and load direction of the crack do not show excessive sensitivity to the peeling of the adhesion layer, which provided a theoretical basis for revealing the essential reason for the bond failure effect of cemented carbide inserts.
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