An Investigation of the Predicting Capabilities of a Variable Flow Stress Machining Theory

2001 ◽  
Author(s):  
P. Mathew
Keyword(s):  
Flow Stress ◽  
Material Flow ◽  
Three Dimensional ◽  
Experimental Results ◽  
Two Dimensional ◽  
Variable Flow ◽  
Comparative Results ◽  
Intermittent Cutting ◽  
Theoretical Results ◽  
Modelling Approach

Abstract The Oxley Machining Theory, which has been developed over the last 40 years, is presented in this paper. The capability of the model is described with its initial two-dimensional machining approach followed by the extension to the generalised model for three-dimensional machining. The theoretical results from the model are compared with the experimental results to determine the model capability. A brief description of the work associated with the effect of strain hardening at the interface is presented and comparative results are shown. A further extension of the model to intermittent cutting process of reaming is also presented and a comparison with the experimental results indicates the model developed is quite capable of predicting cutting forces for reaming. In explaining the results obtain, the assumptions made are explained and the inputs required. The limitations of the modelling approach are presented. It is pointed out that the Oxley model is a versatile model as long as proper description of the material flow stress properties is presented.

Part II: Steady aerofoil-spoiler characteristics

1987 ◽  
Vol 91 (908) ◽  
pp. 359-366
Keyword(s):  
Separated Flow ◽  
Experimental Results ◽  
Surface Singularity ◽  
Separation Region ◽  
Two Dimensional ◽  
Trailing Edge ◽  
Singularity Method ◽  
Total Head ◽  
Low Speeds ◽  
Theoretical Results

Summary A surface singularity method has been formulated to predict two-dimensional spoiler characteristics at low speeds. Vorticity singularities are placed on the aerofoil surface, on the spoiler surface, on the upper separation streamline from the spoiler tip and on the lower separation streamline from the aerofoil trailing edge. The separation region is closed downstream by two discrete vortices. The flow inside the separation region is assumed to have uniform total head. The downstream extent of the separated wake is an empirical input. The flows both external and internal to the separated regions are solved. Theoretical results have been obtained for a range of spoiler-aerofoil configurations which compare reasonably with experimental results. The model is deficient in that it predicts a higher compression ahead of the spoiler than obtained in practice. Furthermore, there is a minimum spoiler angle below which a solution is not possible; it is thought that this feature is related to the physical observation that at small spoiler angles, the separated flow from the spoiler reattaches on the aerofoil upper surface ahead of the trailing edge.

scholarly journals TSUNAMI GENERATION AND PROPAGATION

1972 ◽  
Vol 1 (13) ◽  
pp. 146
Author(s):  
Joseph L. Hammack ◽  
Frederic Raichlen
Keyword(s):  
Linear Theory ◽  
Source Region ◽  
Three Dimensional ◽  
Frequency Dispersion ◽  
Nonlinear Effects ◽  
Its Region ◽  
Experimental Results ◽  
Specific Class ◽  
Two Dimensional ◽  
Three Dimensional Models

A linear theory is presented for waves generated by an arbitrary bed deformation {in space and time) for a two-dimensional and a three -dimensional fluid domain of uniform depth. The resulting wave profile near the source is computed for both the two and three-dimensional models for a specific class of bed deformations; experimental results are presented for the two-dimensional model. The growth of nonlinear effects during wave propagation in an ocean of uniform depth and the corresponding limitations of the linear theory are investigated. A strategy is presented for determining wave behavior at large distances from the source where linear and nonlinear effects are of equal magnitude. The strategy is based on a matching technique which employs the linear theory in its region of applicability and an equation similar to that of Korteweg and deVries (KdV) in the region where nonlinearities are equal in magnitude to frequency dispersion. Comparison of the theoretical computations with the experimental results indicates that an equation of the KdV type is the proper model of wave behavior at large distances from the source region.

Matrix Representation and Prediction of Three-Dimensional Cutting Forces

1977 ◽  
Vol 99 (4) ◽  
pp. 828-834 ◽  
Author(s):  
J. A. Kirk ◽  
D. K. Anand ◽  
C. McKindra
Keyword(s):  
Cutting Forces ◽  
Metal Cutting ◽  
Present Model ◽  
Cutting Tool ◽  
Matrix Representation ◽  
Three Dimensional ◽  
Experimental Results ◽  
Analytical Models ◽  
Two Dimensional ◽  
The Matrix

Matrix geometry techniques are applied to predicting three-dimensional cutting forces. In the present model a specific cutting plane is located and two-dimensional metal cutting theory is applied. Force predictions in this plane are then matrix transformed to three orthogonal forces acting on the cutting tool. Experimental results show the matrix model accurately predicts three-dimensional cutting forces in turning of long slender workpieces. Experimental results are also compared to other analytical models described in the literature.

Altitude Aiding for GPS Systems using Elevation Map Datasets

2002 ◽  
Vol 55 (3) ◽  
pp. 451-462 ◽  
Author(s):  
P. Ptasinski ◽  
F. Cecelja ◽  
W. Balachandran
Keyword(s):  
Navigation System ◽  
Three Dimensional ◽  
Experimental Results ◽  
Two Dimensional ◽  
System A ◽  
Gps System ◽  
Positioning Algorithm

This paper reports the development of a DGPS navigation system integrated with altitude aiding. In this system, a digital height dataset is used for altitude augmentation. A two-dimensional (2-D) positioning algorithm is discussed and modified based on previous publications. The developed algorithm was implemented on the Brunel Inverse DGPS system. The performance of the new developed system is experimentally verified and compared with three-dimensional (3-D) GPS and DGPS systems. The experimental results showed 86% availability of positioning services; whereas for the 3-D GPS system alone, the availability was only 63% of time. In addition, the accuracy of the system was improved from 7.1 to 6.1 m (RMS) for GPS and from 6.0 to 5.1 m (RMS) for DGPS when compared to standalone 3-D modes.

A numerical scheme for shock propagation in three dimensions

1988 ◽  
Vol 416 (1850) ◽  
pp. 179-198 ◽  
Keyword(s):  
Numerical Scheme ◽  
Three Dimensional ◽  
Experimental Results ◽  
Three Dimensions ◽  
Shock Propagation ◽  
Two Dimensional ◽  
Shock Surface ◽  
Shock Dynamics ◽  
Geometrical Shock Dynamics ◽  
Three Space

A numerical scheme for shock propagation in three space dimensions is presented. The motion of the leading shock surface is calculated by using Whitham’s theory of geometrical shock dynamics. The numerical scheme is used to examine the focusing of initially curved shock surfaces and the diffraction of shocks in a pipe with a 90° bend. Numerical and experimental results for the corresponding two-dimensional or axi-symmetrical cases are used to compare with the new and more complicated three-dimensional results.

3-D Video Enhancemnt Based on Histogram Equalization and Edge Sharpening

2013 ◽  
Vol 333-335 ◽  
pp. 1129-1133 ◽  
Author(s):  
Yi Min Qiu ◽  
Shi Hong Chen ◽  
Yi Zhou ◽  
Ying Wang
Keyword(s):  
Stereo Vision ◽  
Three Dimensional ◽  
Subjective Assessment ◽  
Histogram Equalization ◽  
Research Field ◽  
Experimental Results ◽  
Two Dimensional ◽  
Video Mode ◽  
Equalization Method ◽  
Edge Sharpening

With the development of stereo vision, much more attention has paid from two-dimensional to three-dimensional (3-D) spaces, research on 3-D image/video becomes an inevitable trend presently. We present a novel research field that focused on the enhancement of 3-D videos, using two different 3-D videos and enhancing them with histogram equalization and edge sharpening algorithms. And we utilize the subjective assessment in the experiments. The experimental results show that the edge sharpening method has better effect than the histogram equalization method in 3-D video mode. But we also find some problems that both methods have blurred edges.

Anomalous Frictional Behavior in Collisions of Thin Disks Revisited

2008 ◽  
Vol 75 (2) ◽  
Author(s):  
Rahul Mourya ◽  
Anindya Chatterjee
Keyword(s):  
Contact Point ◽  
Single Point ◽  
Three Dimensional ◽  
Experimental Results ◽  
Two Dimensional ◽  
View Point ◽  
Frictional Behavior ◽  
Finite Element Calculations ◽  
Thin Plastic ◽  
Thin Disks

In prior work, Calsamiglia et al. (1999, “Anomalous Frictional Behavior in Collisions of Thin Disks,” ASME J. Appl. Mech., 66, pp. 146–152) reported experimental results of collisions between thin plastic disks and a relatively rigid steel barrier. In those experiments, it was observed that, contrary to a commonly held assumption in rigid body collision modeling, the ratio of tangential to normal components of the contact impulse could be substantially less than the friction coefficient even for collisions where the disk contact point did not reverse its velocity direction (i.e., for sliding collisions). In those experiments, the disk’s edges were rounded to make the contact less sensitive to machining imperfections. While such impact/contact is nominally at a single point, the rounded edges make the interaction three dimensional (from the view point of analyzing deformations). Here, we revisit that problem computationally, but model the edges as flat, making the problem two dimensional. Our finite element calculations (ABAQUS) do not reproduce the anomalous frictional interactions observed in those experiments, suggesting that rounding of the edges, among other possibilities, may have played a significant role in the experimental results.

Study on Hydrodynamic Torque of a Butterfly Valve

2005 ◽  
Vol 128 (1) ◽  
pp. 190-195 ◽  
Author(s):  
Ju Yeop Park ◽  
Myung Kyoon Chung
Keyword(s):  
Iterative Scheme ◽  
Three Dimensional ◽  
Physical Reality ◽  
Two Dimensional ◽  
Butterfly Valve ◽  
Valve Design ◽  
Conventional Model ◽  
Torque Coefficient ◽  
Theoretical Results ◽  
Valve Model

Since knowledge on hydrodynamic torque of a butterfly valve is very important for butterfly valve design, its hydrodynamic torque is investigated theoretically. For this, a recently developed two-dimensional butterfly valve model is solved through the free-streamline theory with a newly devised iterative scheme and the resulting two-and three-dimensional torque coefficients are compared with previous theoretical results based on the conventional butterfly valve model and experiments. Comparison shows that the improvement due to the new butterfly valve model is marginal. That is, the three-dimensional torque coefficient is well represented by the new model. Otherwise, the two-dimensional torque coefficient is well predicted by the conventional model. In spite this fact, the present results can be used in further researches on butterfly valves because the improved butterfly valve model is mathematically correct and reflects physical reality more correctly than the conventional valve model.

Prediction of High Speed Machining Cutting Forces Using a Variable Flow Stress Machining Theory

2011 ◽  
Vol 188 ◽  
pp. 128-133 ◽  
Author(s):  
Philip Mathew
Keyword(s):  
Flow Stress ◽  
Cutting Forces ◽  
High Speed ◽  
Experimental Results ◽  
The Other ◽  
Cutting Conditions ◽  
High Speed Machining ◽  
Variable Flow ◽  
Machining Conditions

A variable flow stress machining theory is described where it is used to predict the cutting forces associated with High Speed Machining (HSM) process. The predicted and experimental results for different materials and different cutting conditions are presented and compared and it is shown that the theory developed is capable of predicting the cutting forces and the other parameters associated with the HSM process. The extension of the theory to HSM has been successful within the machining conditions presented here in this paper. Further work is necessary to improve this theory further.

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