Yucan Fu

Bio: Yucan Fu is an academic researcher from Nanjing University of Aeronautics and Astronautics. The author has contributed to research in topics: Grinding & Grinding wheel. The author has an hindex of 27, co-authored 136 publications receiving 2317 citations. Previous affiliations of Yucan Fu include Nanjing University.

Grinding performance of textured monolayer CBN wheels: Undeformed chip thickness nonuniformity modeling and ground surface topography prediction

Abstract: The ground surface roughness and topography are commonly used to characterize the surface finishing. In the application of textured monolayer CBN wheels, the nonuniformity of wheel topology will render a nonuniform undeformed chip thickness which greatly affects the ground surface. In order to predict the ground surface topography more accurately and efficiently, grinding experiment has been conducted in the current study, with measured grinding wheel topology. The measured surface topology of textured monolayer CBN wheels has been reconstructed by using the Johnson transformation and its inverse transformation. The influence of wheel topology evolution on the undeformed chip thickness nonuniformity has been determined with an improved model. It has been found the ground surface roughness is improved with a continuous reducing undeformed chip thickness nonuniformity. The percentage of active grains, the mean value and standard deviation of undeformed chip thickness have been found the main factors in determining the surface roughness. The reconstructed wheel surface topology has been used to predict the workpiece topography in different stages of the grinding process.

Influence of grain wear on material removal behavior during grinding nickel-based superalloy with a single diamond grain

Abstract: In order to explore the effect of grain wear on material removal behavior during grinding nickel-based superalloy Inconel 718, the grinding experiment with a single diamond grain was carried out. The variations of grain wear, grinding force and force ratio, and pile-up ratio were investigated under the conditions of undeformed chip thickness (UCT) ranging from 0.2 to 1 µm. The results show that a critical UCT value, such as 0.3 µm, could be determined according to the pile-up ratio and could also be used to quantify the material removal process. The wear behavior of a diamond grain shows four types, such as crescent depression on the rake face, abrasion on the flank face, grain micro-fracture, and grain macro-fracture. Furthermore, these classifications are determined by the dwell time of rubbing, ploughing and cutting at different UCT values applied. The grinding force ratio increases with increasing of the negative rake angle of a diamond grain. In the rubbing and ploughing stages, the material removal efficiency is proportional to the wear width on the rake face. However, in the cutting stage, the material removal efficiency is diminished in the absence process of crescent depression.

A reflectance model for computer graphics

Abstract: This paper presents a new reflectance model for rendering computer synthesized images. The model accounts for the relative brightness of different materials and light sources in the same scene. It describes the directional distribution of the reflected light and a color shift that occurs as the reflectance changes with incidence angle. The paper presents a method for obtaining the spectral energy distribution of the light reflected from an object made of a specific real material and discusses a procedure for accurately reproducing the color associated with the spectral energy distribution. The model is applied to the simulation of a metal and a plastic.

Maximum undeformed equivalent chip thickness for ductile-brittle transition of zirconia ceramics under different lubrication conditions

Abstract: This study investigates the critical maximum undeformed equivalent chip thickness for ductile-brittle transition (DBhmax-e) of zirconia ceramics under different lubrication conditions. A DBhmax-e model is developed through geometry and kinematics analyses of ductile-mode grinding. Result shows that DBhmax-e decreases with increasing friction coefficient (μ). An experimental investigation is then conducted to validate the model and determine the effect of dry lubrication, minimum quantity lubrication (MQL), and nanoparticle jet minimum quantity lubrication (NJMQL) conditions on DBhmax-e. According to different formation mechanisms of debris, the grinding behavior of zirconia ceramics is categorized into elastic sliding friction, plastic removal, powder removal, and brittle removal. Grinding forces per unit undeformed chip thickness (Fn/h and Ft/h) are obtained. The lubrication condition affects the normal force and ultimately influences the resultant force on workpiece. In comparison with dry grinding (DBhmax-e = 0.8 μm), MQL and NJMQL grinding processes increase DBhmax-e by 0.99 and 1.79 μm respectively; this finding is similar to model result. The theoretical model is then assessed by different volume fractions of nanofluids under NJMQL condition with an average percentage error of less than 8.6%.