Hydrodynamic Fluid Pressure in Grinding Zone During Grinding With Metal-Bonded Diamond Wheels

1999 ◽  
Vol 122 (3) ◽  
pp. 603-608 ◽  
Author(s):  
Bo Zhang ◽  
Akira Nakajima
Keyword(s):  
Theoretical Analysis ◽  
Hydrodynamic Force ◽  
Fluid Pressure ◽  
Hydrodynamic Pressure ◽  
Grinding Force ◽  
Experimental Results ◽  
Theoretical Studies ◽  
Wheel Surface ◽  
Grinding Fluid ◽  
Experimental And Theoretical Studies

Experimental and theoretical studies on hydrodynamic fluid pressure were conducted for the cases of plane grinding with nonporous metal bonded diamond wheels of SD140 and SD4000. Hydrodynamic force was successfully separated from the actual grinding force using the device developed in this study. Both experimental results and theoretical analysis showed that the effect of side leakage of grinding fluid on hydrodynamic pressure is negligible under grinding condition and therefore the infinite width cylindrical bearing theory is applicable. The effective clearance includes the effects of both the protrusion of cutting points and the waviness of the wheel surface for SD140. However, for a fine wheel such as SD4000, the waviness is predominant. Hydrodynamic force predominates normal grinding force even for a coarse wheel as SD140. [S0742-4787(00)01302-3]

Application of Lubrication Theory to Near-Dry Green Grinding – Feasibility Analysis

2008 ◽  
Vol 44-46 ◽  
pp. 135-142 ◽  
Author(s):  
Chang He Li ◽  
Ya Li Hou ◽  
Shi Chao Xiu ◽  
Guang Qi Cai
Keyword(s):  
Contact Zone ◽  
Fluid Pressure ◽  
Hydrodynamic Pressure ◽  
Green Manufacturing ◽  
Lubrication Theory ◽  
Experimental Results ◽  
Cutting Fluid ◽  
Machining Accuracy ◽  
Navier Stokes Equation ◽  
Grinding Fluid

This paper describes an investigation about the grinding fluid optimization supply based on lubrication theory. The models for three-dimensional hydrodynamic flow pressure in contact zone between wheel and work are presented based on Navier-Stokes equation and continuous formulae. It is well known that hydrodynamic fluid pressure generates due to this fluid flux, and that it affects overall grinding resistance and machining accuracy. Moreover, conventional methods of delivering grinding fluid, i.e. flood delivery via a shoe or jet delivery tangential to the wheel via a nozzle, have been proved that they can not fully penetrate this boundary layer and thus, the majority of the cutting fluid is deflected away from the grinding zone. Therefore, in this paper, a new delivery method of grinding fluid, the minimum quantity lubricant (MQL)-near-dry green grinding is presented and analyzed for it not only reduces hydrodynamic lift force but also reduces grinding fluid cost to achieve green manufacturing. Experiments have been carried out to validate the performance of the MQL supply compared with conventional flood cooling. The experimental results have shown that the theoretical model is in agreement with experimental results and the model can well forecast hydrodynamic pressure distribution at contact zone between and workpiece and the MQL supply in grinding is feasible. Experiments have also been carried out to evaluate the performance of the MQL technology compared with conventional flood cooling. Experimental data indicate that the proposed method does not negatively affect to the surface integrity and the process validity has been verified.

Role of the metal cation types around VO4 groups on the nonlinear optical behavior of materials: experimental and theoretical analysis

2016 ◽  
Vol 45 (36) ◽  
pp. 14394-14402 ◽  
Author(s):  
Xin Su ◽  
Zhihua Yang ◽  
Guopeng Han ◽  
Ying Wang ◽  
Ming Wen ◽  
...  
Keyword(s):  
Theoretical Analysis ◽  
Metal Cation ◽  
Nonlinear Optical ◽  
Theoretical Studies ◽  
Optical Behavior ◽  
Experimental And Theoretical Studies

We combined experimental and theoretical studies of βII-Li3VO4, KCd4(VO4)3 and Ca3(VO4)2 crystals, which turns out that the metal cation types and coordination around VO4 groups, the distorted and parallel oriented VO4 tetrahedron, could produce the large SHG coefficient.

Effect of Objective Normalization and Penalty Parameter on Penalty Boundary Intersection Decomposition-Based Evolutionary Many-Objective Optimization Algorithms

2020 ◽  
pp. 1-30
Author(s):  
Lei Chen ◽  
Kalyanmoy Deb ◽  
Hai-Lin Liu ◽  
Qingfu Zhang
Keyword(s):  
Theoretical Analysis ◽  
Experimental Results ◽  
Decomposition Algorithms ◽  
Theoretical Studies ◽  
Distance Metrics ◽  
Penalty Parameter ◽  
True Nature ◽  
Normalization Strategy ◽  
Normalization Process ◽  
Theoretical Results

An objective normalization strategy is essential in any evolutionary multiobjective or many-objective optimization (EMO or EMaO) algorithm, due to the distance calculations between objective vectors required to compute diversity and convergence of population members. For the decomposition-based EMO/EMaO algorithms involving the Penalty Boundary Intersection (PBI) metric, normalization is an important matter due to the computation of two distance metrics. In this article, we make a theoretical analysis of the effect of instabilities in the normalization process on the performance of PBI-based MOEA/D and a proposed PBI-based NSGA-III procedure. Although the effect is well recognized in the literature, few theoretical studies have been done so far to understand its true nature and the choice of a suitable penalty parameter value for an arbitrary problem. The developed theoretical results have been corroborated with extensive experimental results on three to 15-objective convex and non-convex instances of DTLZ and WFG problems. The article, makes important theoretical conclusions on PBI-based decomposition algorithms derived from the study.

Numerical Simulation of Hydrodynamic Fluid Pressure in Grinding Zone with Resin-Bonded Diamond Grinding Wheel

2010 ◽  
Vol 426-427 ◽  
pp. 668-673
Author(s):  
Ya Li Hou ◽  
Chang He Li
Keyword(s):  
Numerical Simulation ◽  
Fluid Pressure ◽  
Hydrodynamic Pressure ◽  
Coolant Fluid ◽  
Grinding Wheel ◽  
Maximum Pressure ◽  
Delivery Mode ◽  
Diamond Grinding Wheel ◽  
Diamond Grinding ◽  
Grinding Fluid

In the grinding process, grinding fluid is delivered for the purposes of chip flushing, cooling, lubrication and chemical protection of work surface. Lubrication and cooling are the most important roles provided by a grinding fluid. Hence, the conventional method of flood delivering coolant fluid by a nozzle in order to achieve high process performance purposivelly. However, hydrodynamic fluid pressure can be generated ahead of the grinding zone due to the wedge effect between wheel peripheral surface and part surface. In the paper, a theoretical hydrodynamic pressure modeling is presented for flow of coolant fluid through the grinding zone in flood delivery mode in the surface grinding using resin-bonded diamond grinding wheel, which based on Navier-Stokes equation and continuous formulae. The numerical simulation results showed that the hydrodynamic pressure was proportion to grinding wheel velocity, and inverse proportion to the minimum gap between wheel and workpiece and the maximum pressure was generated just in the minimum clearance region in which higher fluid pressure gradient occur. It can also be concluded the pressure distribution was uniform in the direction of width of wheel except at the edge of wheel because of the side-leakage.

Theoretical Analysis and Experimental Investigation into Hydrodynamic Pressure and Coolant Lift Force in Flood Delivery Grinding

2010 ◽  
Vol 97-101 ◽  
pp. 1836-1840
Author(s):  
Ya Li Hou ◽  
Fu Xin Yao ◽  
Chang He Li ◽  
Yu Cheng Ding
Keyword(s):  
Pressure Distribution ◽  
Contact Zone ◽  
High Performance ◽  
Fluid Pressure ◽  
Hydrodynamic Pressure ◽  
Experimental Results ◽  
Coolant Fluid ◽  
Grinding Wheel ◽  
Maximum Pressure ◽  
Work Surface

In the grinding process, conventional method of flood delivering coolant fluid by a nozzle in order to achieve high performance finishing. However, hydrodynamic fluid pressure can be generated ahead of the contact zone due to the wedge effect between wheel peripheral surface and work surface. In the paper, a theoretical hydrodynamic pressure modeling is presented for flow of coolant fluid through the grinding zone in flood delivery grinding. Moreover, coolant induced force can be calculated by integrate the hydrodynamic pressure distribution over the whole contact length. The theoretical results show that the hydrodynamic pressure was proportion to grinding wheel velocity, and inverse proportion to the minimum gap between wheel and work surface and the maximum pressure value was generated just in the minimum gap region in which higher fluid pressure gradient occuring. It can also be concluded the pressure distribution was uniform in the direction of width of wheel except at the edge of wheel because of the side-leakage. Furthermore, the hydrodynamic pressure and coolant induced force at wedge-like zone were also investigated experimentally. The experimental results show the theoretical model is agreement with experimental results and the model can well forecast hydrodynamic pressure distribution at contact zone between grinding wheel and workpiece.

Experimental and Theoretical Studies on Effects of Heterogeneity on Channeling in Waterflooding

2012 ◽  
Vol 518-523 ◽  
pp. 4084-4087 ◽  
Author(s):  
Wei Wang ◽  
Xiang An Yue ◽  
Ren Bao Zhao ◽  
Hui Yang
Keyword(s):  
Theoretical Analysis ◽  
Water Flooding ◽  
Theoretical Studies ◽  
Development Cost ◽  
Heterogeneous Reservoirs ◽  
Water Breakthrough ◽  
Physical Experiments ◽  
Water Cut ◽  
Experimental And Theoretical Studies ◽  
Layer Series

Water channeling is easy to occur during the process of water flooding in heterogeneous reservoirs. It leads to injected water noneffective cycling, the recovery decreasing and the development cost rising. By means of physical experiments and theoretical analysis, characteristics of water channeling are studied in different heterogeneous reservoirs. The result shows that when permeability contrast is lesser than 5.88, the development performance of reservoirs is similar to homogeneous reservoirs and water cut rises slowly after water breakthrough. If permeability contrast is higher than 5.88, the recovery curve has an inflexion, water cut rises rapidly and water channeling is easy to occur after breakthrough. Therefore, permeability contrast should be lesser than 5.88 in terms of layer series division in interlayer heterogeneous reservoirs. Measures must be taken to avoid water channeling when permeability contrast is higher than 5.88 in inner heterogeneous reservoirs.

Methods of Reducing the Response of Integrally Stiffened Structures to Random Pressures

1969 ◽  
Vol 91 (4) ◽  
pp. 1203-1209 ◽  
Author(s):  
B. L. Clarkson ◽  
F. Cicci
Keyword(s):  
Spectral Density ◽  
Broad Band ◽  
Experimental Results ◽  
Significant Response ◽  
Theoretical Studies ◽  
Frequency Range ◽  
Efficient System ◽  
Stiffened Structures ◽  
Experimental And Theoretical Studies

Experimental and theoretical studies of the response of integrally stiffened skin structures to random acoustic pressures are described. Typical structures are lightly damped and show significant response in the frequency range 100 to 2000 Hz. Some methods of increasing the damping are described and experimental results quoted. In the most efficient system investigated a damping treatment adding only 2 percent by weight to the structure reduced the rms stress by a factor of approximately three for the case of broad band excitation having a constant spectral density in the range 100 to 1000 Hz.

The Stabilizing Effect of Pre-Equilibria: A Trifluoromethyl Complex as CF2 Reservoir in Catalytic Olefin Difluorocarbenation

2020 ◽  
Author(s):  
Thomas Louis-Goff ◽  
Huu Vinh Trinh ◽  
Eileen Chen ◽  
Arnold L. Rheingold ◽  
Christian Ehm ◽  
...  
Keyword(s):  
High Selectivity ◽  
Side Reactions ◽  
Theoretical Studies ◽  
Attractive Feature ◽  
Catalyst Recovery ◽  
Wide Range ◽  
Stabilizing Effect ◽  
Experimental And Theoretical Studies

A new, efficient, catalytic difluorocarbenation of olefins to give 1,1-difluorocyclopropanes is presented. The catalyst, an organobismuth complex, uses TMSCF<sub>3</sub> as a stoichiometric difluorocarbene source. We demonstrate both the viability and robustness of this reaction over a wide range of alkenes and alkynes, including electron-poor alkenes, to generate the corresponding 1,1-difluorocyclopropanes and 1,1-difluorocyclopropenes. Ease of catalyst recovery from the reaction mixture is another attractive feature of this method. In depth experimental and theoretical studies showed that the key difluorocarbene-generating step proceeds through a bismuth non-redox synchronous mechanism generating a highly reactive free CF<sub>2</sub> in an endergonic pre-equilibrium. It is the reversibility when generating the difluorocarbene that accounts for the high selectivity, while minimizing CF<sub>2</sub>-recombination side-reactions.

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