The role of oxide layers on tungsten carbide tools in metal cutting was investigated using oxide-... more The role of oxide layers on tungsten carbide tools in metal cutting was investigated using oxide-treated tools. It is shown that the structural change of the subsurface of the tool takes place due to mass diffusion between the oxide and the substrate, which enhances the metal cutting properties of tungsten carbide tools. The tools were coated with titanium dioxide and heated in a vacuum of 10−4 torr. These oxide-treated tools and the untreated tools were diffusion-bonded to steel in a vacuum so as to determine the influence of the oxide treatment on mass diffusion. The changes in the hardness of these bonded specimens were measured after maintaining them at high temperatures for various durations. The hardness across the interface of the bonding changed sharply in the case of the untreated tools, the hardness of steel increasing and that of tungsten carbide decreasing. In the case of the oxide-treated tools, the hardness did not change appreciably. Cutting experiments showed that the cutting force and the crater wear decreased by about 12 to 20 percent after the oxide treatment.
... As in the Cassie-Baxter rough wetting theory, structure can only reduce the interaction betwe... more ... As in the Cassie-Baxter rough wetting theory, structure can only reduce the interaction between a ... FR221 is clearly a function of DP221 only and therefore, equation 7 shows that there is ... Since this investigation is meant to be a general investigation into the feasibility of the use of ...
Many metal processing techniques are dictated by equilibrium thermodynamics and the kinetics of p... more Many metal processing techniques are dictated by equilibrium thermodynamics and the kinetics of phase transformation. Consequently, an alloy of a specific chemical composition must be processed in a unique manner to obtain the desired postprocessing microstructure and, therefore, the properties. In this respect conventional processes are coupled; any change in any one process variable and/or the chemical composition affects all the properties of the metal part. This limitation can be eliminated by using orthonormal processing techniques which allow the uncoupling of processing and properties. Examples of Orthonormal Metal Processing (OMP) techniques are given in this paper. A newly developed process comprises the impingement of two or more streams of liquid metal components (which mix due to turbulent eddies) and freezing the liquid mixture rapidly. This process can create a variety of microstructures of various metal compositions. Part 1 of this paper describes the concept and theory. Part 2 presents the experimental results.
"Science and Technology of Polymer Processing" presents a comprehensive treatment of th... more "Science and Technology of Polymer Processing" presents a comprehensive treatment of the fundamental aspects of and recent developments in polymer processing, a field that has become increasingly important in terms of applications to the durability of machines and structures and to problems of energy dissipation by frictional means.Major sections in the book are Topography and Surface Quality, Physical and Chemical Properties of Surfaces, Interface Phenomena, Friction, Wear, Wear Prevention, Boundary and Solid Lubrication, Hydrodynamic Lubrication, Thermo-Mechanic Effects in Sliding Interaction, Applications, and Recent Advances in Tribology.
A new cost-effective process has been developed for synthesizing high-performance MMCs with excel... more A new cost-effective process has been developed for synthesizing high-performance MMCs with excellent properties. It utilizes turbulent eddies and jet impingement for mixing two or more liquid metal streams at turbulent velocities in a chamber having an intricate geometry. Research and development of the method has resulted in commercial manufacture of boride dispersion strengthened copper alloys.
Evolutionary design systems apply principles inspired from biological evolution to automate machi... more Evolutionary design systems apply principles inspired from biological evolution to automate machine design. These systems have been shown to generate simple designs for simple tasks — but their practical ability to scale up to higher complexities remains questioned. One of the keys to accomplishing higher-level evolutionary design is the ability of the process to identify and reuse knowledge discovered at lower levels, thus scaling its search capacity. One way to capture this knowledge is in the form of reusable building blocks — modules. In this paper we define modularity and discuss several approaches to promoting modularity in evolutionary design systems. In particular, we propose a new mechanism that can enhance modularization. This mechanism is based on the observation that designs that exhibit modularity have higher adaptability and consequently have better survival rates under changing requirements. Contrary to other techniques, this is a weak (indirect) formulation that docs not require representation of partial solutions or definition of a genotype from which a design is developed. We demonstrate this principle on an abstract general design problem on which modularity can be statistically quantified.
Robotics and Computer-integrated Manufacturing, 1985
The D~ign A~oms have b~n advanced as a m~hod~ogy ~r use ~ ev~uafing deigns ~ produ~s and proce~ ~... more The D~ign A~oms have b~n advanced as a m~hod~ogy ~r use ~ ev~uafing deigns ~ produ~s and proce~ ~s. To dMe, however, ~e Ax~ms have b~n availab~ o~y ~ an inform~ ~t ~ ru~ In order ~r ~e r~afions~ps among thee ru~s ~ be ~ished defi~fiv~y, and ~ ~cili~ ~e u~ ~ compu~ ~r d~i~o~ ma~ng ~ ~e~gn, ~e A~oms have b~n exposed he~ wi~ ma~emafical preci~on. T~s paper investigat~ ~e use d ~mbofic ~c ~r t~s purple. The re~ ~ that one deign ru~ wh~h was pre~ou~y believed ~ be a coroHa~ ~ ~e Independence A~om ~ a~ually ~own ~ have ~e ~me form~ Mructu~. S~ ~her propositions are ~en to be de~vafiv~ of the A~oms ~us ~me m~d ~mpfions, w~ s~l others wo~d ~q~ ~corporating ~her ~ws d na~ ~ add~on ~ ~e exiting A~oms. Anther impor~ ~ ~ ~e re,arch ~ • ~ ~afivg ~e a~oms ~ ~mbofic logic sugg~ts how ~ may te encoded ~ a logical programming language such ~ Prolog. An ov~aH a~t~ ~r an a~omafi~ expe~ ~em ~ ~e~ p~n~d.
Means of reducing the flow‐induced residual stresses in injection molded parts through optimizati... more Means of reducing the flow‐induced residual stresses in injection molded parts through optimization of the thermal history of the process are presented. An approach through the use of a passive insulation layer with low thermal inertia on the cavity surface was investigated. The passive insulation layer prevents the polymer melt from freezing during mold filling and allows the flow‐induced stresses to relax after the filling. The criteria for the optimal thermal properties and the required thickness of the layer are presented. A numerical simulation model of non‐isothermal filling and cooling of viscoelastic materials was also used to understand the molding process and to evaluate this approach. This model predicts the stress development and relaxation in the molding cycle. Both simulation and experimental results show that the final stresses in the molded parts can be reduced significantly with the use of an insulation layer. This technique can also be applied to other molding or forming processes in order to decouple the material flow and cooling process for minimum residual stresses in the molded parts.
... was supported by a variety of experimental results, the most convincing one being the correla... more ... was supported by a variety of experimental results, the most convincing one being the correlation between the ... on Hard Material Tool Technology, Pittsburgh, 1976, pp. ... 37 MV Swain, Microscopic observations of abrasive wear of polycrystalline alumina, Wear, 35(1975) 185 - 189 ...
In this paper, we have presented a novel design for a customizable automotive suspension system w... more In this paper, we have presented a novel design for a customizable automotive suspension system with independent control of stiffness, damping and ride-height; and demonstrated the concept through a suspension prototype. The major motivation for this design is to avoid the trade-offs, involved in suspension design, which arise from the conflicting requirements of comfort and handling. The objective of this paper is to explore the possible applications of variable stiffness and variable ride-height suspension system to achieve improved vehicle dynamics. The capability of achieving the desired performance depending on user preference, vehicle speed, road conditions and maneuvering inputs using the proposed system is demonstrated. The application of variable stiffness to achieve real-time alteration of pitch and bounce motion centers, and real time alteration of anti-pitch and anti-dive characteristics is discussed. Moreover the possibility of ensuring stability through real-time alteration of understeer-oversteer characteristics is explored. Numerous other applications of variable stiffness are possible as stiffness affects almost every aspect of ride and handling. Since the proposed system is the first system with independent control of ride-height and stiffness, the research area has been virtually unexplored. Hence it is also the objective of this paper to initiate further research in this area and to create a suitable strategy for controlling all the adaptive parameters to get improved performance.
The role of oxide layers on tungsten carbide tools in metal cutting was investigated using oxide-... more The role of oxide layers on tungsten carbide tools in metal cutting was investigated using oxide-treated tools. It is shown that the structural change of the subsurface of the tool takes place due to mass diffusion between the oxide and the substrate, which enhances the metal cutting properties of tungsten carbide tools. The tools were coated with titanium dioxide and heated in a vacuum of 10−4 torr. These oxide-treated tools and the untreated tools were diffusion-bonded to steel in a vacuum so as to determine the influence of the oxide treatment on mass diffusion. The changes in the hardness of these bonded specimens were measured after maintaining them at high temperatures for various durations. The hardness across the interface of the bonding changed sharply in the case of the untreated tools, the hardness of steel increasing and that of tungsten carbide decreasing. In the case of the oxide-treated tools, the hardness did not change appreciably. Cutting experiments showed that the cutting force and the crater wear decreased by about 12 to 20 percent after the oxide treatment.
... As in the Cassie-Baxter rough wetting theory, structure can only reduce the interaction betwe... more ... As in the Cassie-Baxter rough wetting theory, structure can only reduce the interaction between a ... FR221 is clearly a function of DP221 only and therefore, equation 7 shows that there is ... Since this investigation is meant to be a general investigation into the feasibility of the use of ...
Many metal processing techniques are dictated by equilibrium thermodynamics and the kinetics of p... more Many metal processing techniques are dictated by equilibrium thermodynamics and the kinetics of phase transformation. Consequently, an alloy of a specific chemical composition must be processed in a unique manner to obtain the desired postprocessing microstructure and, therefore, the properties. In this respect conventional processes are coupled; any change in any one process variable and/or the chemical composition affects all the properties of the metal part. This limitation can be eliminated by using orthonormal processing techniques which allow the uncoupling of processing and properties. Examples of Orthonormal Metal Processing (OMP) techniques are given in this paper. A newly developed process comprises the impingement of two or more streams of liquid metal components (which mix due to turbulent eddies) and freezing the liquid mixture rapidly. This process can create a variety of microstructures of various metal compositions. Part 1 of this paper describes the concept and theory. Part 2 presents the experimental results.
"Science and Technology of Polymer Processing" presents a comprehensive treatment of th... more "Science and Technology of Polymer Processing" presents a comprehensive treatment of the fundamental aspects of and recent developments in polymer processing, a field that has become increasingly important in terms of applications to the durability of machines and structures and to problems of energy dissipation by frictional means.Major sections in the book are Topography and Surface Quality, Physical and Chemical Properties of Surfaces, Interface Phenomena, Friction, Wear, Wear Prevention, Boundary and Solid Lubrication, Hydrodynamic Lubrication, Thermo-Mechanic Effects in Sliding Interaction, Applications, and Recent Advances in Tribology.
A new cost-effective process has been developed for synthesizing high-performance MMCs with excel... more A new cost-effective process has been developed for synthesizing high-performance MMCs with excellent properties. It utilizes turbulent eddies and jet impingement for mixing two or more liquid metal streams at turbulent velocities in a chamber having an intricate geometry. Research and development of the method has resulted in commercial manufacture of boride dispersion strengthened copper alloys.
Evolutionary design systems apply principles inspired from biological evolution to automate machi... more Evolutionary design systems apply principles inspired from biological evolution to automate machine design. These systems have been shown to generate simple designs for simple tasks — but their practical ability to scale up to higher complexities remains questioned. One of the keys to accomplishing higher-level evolutionary design is the ability of the process to identify and reuse knowledge discovered at lower levels, thus scaling its search capacity. One way to capture this knowledge is in the form of reusable building blocks — modules. In this paper we define modularity and discuss several approaches to promoting modularity in evolutionary design systems. In particular, we propose a new mechanism that can enhance modularization. This mechanism is based on the observation that designs that exhibit modularity have higher adaptability and consequently have better survival rates under changing requirements. Contrary to other techniques, this is a weak (indirect) formulation that docs not require representation of partial solutions or definition of a genotype from which a design is developed. We demonstrate this principle on an abstract general design problem on which modularity can be statistically quantified.
Robotics and Computer-integrated Manufacturing, 1985
The D~ign A~oms have b~n advanced as a m~hod~ogy ~r use ~ ev~uafing deigns ~ produ~s and proce~ ~... more The D~ign A~oms have b~n advanced as a m~hod~ogy ~r use ~ ev~uafing deigns ~ produ~s and proce~ ~s. To dMe, however, ~e Ax~ms have b~n availab~ o~y ~ an inform~ ~t ~ ru~ In order ~r ~e r~afions~ps among thee ru~s ~ be ~ished defi~fiv~y, and ~ ~cili~ ~e u~ ~ compu~ ~r d~i~o~ ma~ng ~ ~e~gn, ~e A~oms have b~n exposed he~ wi~ ma~emafical preci~on. T~s paper investigat~ ~e use d ~mbofic ~c ~r t~s purple. The re~ ~ that one deign ru~ wh~h was pre~ou~y believed ~ be a coroHa~ ~ ~e Independence A~om ~ a~ually ~own ~ have ~e ~me form~ Mructu~. S~ ~her propositions are ~en to be de~vafiv~ of the A~oms ~us ~me m~d ~mpfions, w~ s~l others wo~d ~q~ ~corporating ~her ~ws d na~ ~ add~on ~ ~e exiting A~oms. Anther impor~ ~ ~ ~e re,arch ~ • ~ ~afivg ~e a~oms ~ ~mbofic logic sugg~ts how ~ may te encoded ~ a logical programming language such ~ Prolog. An ov~aH a~t~ ~r an a~omafi~ expe~ ~em ~ ~e~ p~n~d.
Means of reducing the flow‐induced residual stresses in injection molded parts through optimizati... more Means of reducing the flow‐induced residual stresses in injection molded parts through optimization of the thermal history of the process are presented. An approach through the use of a passive insulation layer with low thermal inertia on the cavity surface was investigated. The passive insulation layer prevents the polymer melt from freezing during mold filling and allows the flow‐induced stresses to relax after the filling. The criteria for the optimal thermal properties and the required thickness of the layer are presented. A numerical simulation model of non‐isothermal filling and cooling of viscoelastic materials was also used to understand the molding process and to evaluate this approach. This model predicts the stress development and relaxation in the molding cycle. Both simulation and experimental results show that the final stresses in the molded parts can be reduced significantly with the use of an insulation layer. This technique can also be applied to other molding or forming processes in order to decouple the material flow and cooling process for minimum residual stresses in the molded parts.
... was supported by a variety of experimental results, the most convincing one being the correla... more ... was supported by a variety of experimental results, the most convincing one being the correlation between the ... on Hard Material Tool Technology, Pittsburgh, 1976, pp. ... 37 MV Swain, Microscopic observations of abrasive wear of polycrystalline alumina, Wear, 35(1975) 185 - 189 ...
In this paper, we have presented a novel design for a customizable automotive suspension system w... more In this paper, we have presented a novel design for a customizable automotive suspension system with independent control of stiffness, damping and ride-height; and demonstrated the concept through a suspension prototype. The major motivation for this design is to avoid the trade-offs, involved in suspension design, which arise from the conflicting requirements of comfort and handling. The objective of this paper is to explore the possible applications of variable stiffness and variable ride-height suspension system to achieve improved vehicle dynamics. The capability of achieving the desired performance depending on user preference, vehicle speed, road conditions and maneuvering inputs using the proposed system is demonstrated. The application of variable stiffness to achieve real-time alteration of pitch and bounce motion centers, and real time alteration of anti-pitch and anti-dive characteristics is discussed. Moreover the possibility of ensuring stability through real-time alteration of understeer-oversteer characteristics is explored. Numerous other applications of variable stiffness are possible as stiffness affects almost every aspect of ride and handling. Since the proposed system is the first system with independent control of ride-height and stiffness, the research area has been virtually unexplored. Hence it is also the objective of this paper to initiate further research in this area and to create a suitable strategy for controlling all the adaptive parameters to get improved performance.
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