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Fiber coiling during bladder molding of thermoplastic composites

POLYMER COMPOSITES 1996年第4期17卷 627-636页

作者： Colton, JS Beeson, MS Composites Manufacturing Research Program George W. Woodruff School of Mechanical Engineering Georgia Institute of Technology Atlanta Georgia 30332-0405

An investigation is presented into fiber movement during the consolidation of cylindrical, filament-wound preforms when pressure is applied internally (bladder molding). It is necessary to characterize the fiber movement to predict the final fiber orientation of successful parts as well as to predict which parts will not be successful. Unsuccessful parts have fibers that clump together in thick coils at the interior surface of a part, resulting in an uneven wall thickness and poor mechanical properties. Cylindrical preforms (similar to 7.5 cm in diameter) made from glass fiber (20 mu m in diameter, similar to 50 vol%) coated with polypropylene powder (powder-coated towpregs) were filament-wound in a range of angles, interweaving patterns, and diameters. Trellising, a mode of fiber movement in which the fibers rotate as if they are pinned at the interweaving points, occurs first as the preforms expand. If the preforms ''trellis'' as much as possible without reaching the mold wall, shearing between adjacent fibers must occur to complete the expansion. Coiling occurs when a large amount of shearing is necessary to provide the final expansion needed to bring the preform to the mold diameter. A dimensionless ''coiling'' number is presented that predicts coiling.

关键词： Fiber reinforced plastics

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MICROSTRUCTURE-BASED PROCESSING PARAMETERS OF THERMOPLASTIC COMPOSITE-MATERIALS .1. THEORETICAL-MODELS

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POLYMER COMPOSITES 1994年第1期15卷 34-41页

作者： YANG, HC COLTON, JS Composites Manufacturing Research Program School of Mechanical Engineering Georgia Institute of Technology Atlanta Georgia 30332‐0405

Processing parameters for composites are predicted by new models which are based on the microstructure of the composite. Three types of thermoplastic prepregs are considered, ICI tape, BASF commingled tow, and CCMI powder coated tow. The permeability of the composites depends on their fiber distribution. The elastic behavior of the fiber network compression depends on the fiber orientation. These two are integrated to predict the processing parameters.

关键词： Microstructure

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ONLINE CONSOLIDATION MECHANISMS IN THERMOPLASTIC FILAMENT WINDING

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POLYMER COMPOSITES 1994年第1期15卷 55-63页

作者： CARPENTER, CE COLTON, JS Composites Manufacturing Research Program The Geroge W. Woodruff School of Mechanical Engineering Georgia Institute of Technology Atlanta Georgia 30332‐0405

The on-line consolidation process, using a single roller, in thermoplastic filament winding (tape laying) has been investigated. A one-dimensional, semi-empirical, on-line consolidation process model is proposed that describes the deformation and flow phenomena. The model is used to predict the applied load necessary to achieve a desired fiber volume content of filament wound thermoplastic composite rings consolidated at various process conditions. Composite rings are fabricated from 50 layers of 12K carbon fiber tow APC-2 tape (6 mm wide) on a 178 mm diameter mandrel. It was found that the winding speed had statistically significant effects on the void content, the fiber volume fraction, and the final thickness;whereas the applied load had a statistically significant effect on the final thickness. These results show the effect of shear thinning on the viscoelastic response of the material, facilitating faster processing speeds. The results of the experiments compared well to the consolidation model's predictions.

关键词： Shear thinning

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ONLINE CONSOLIDATION OF THERMOPLASTIC TOWPREG COMPOSITES IN FILAMENT WINDING

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POLYMER COMPOSITES 1994年第6期15卷 436-441页

作者： WAGNER, P COLTON, J Composites Manufacturing Research Program The George W. Woodruff School of Mechanical Engineering Georgia Institute of Technology Atlanta Georgia 30332‐0405

A study of the use of thermoplastic powder coated towpregs in filament winding was conducted. A suitable technique for manufacturing parts with adequate on-line consolidation was identified through an experimental investigation that compared several techniques. This process utilized a single compaction roller on-line consolidation head with hot air guns to obtain consolidation at the lay-down point on the mandrel. The addition of a heated pultrusion die between the creel system and the filament winder was found to produce the best process. Nylon 11/E-glass towpreg was used in this study. The effect of winding speed and compaction force on the quality of the resulting parts was determined in order to optimize the process. Only the speed was found to have a significant effect, with better quality parts being made at higher speed. Observations were also made on parts manufactured with polypropylene and E-glass towpreg, as well as on parts wound with helical patterns.

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Real-time tool wear identification using sensor integration with neural network

Real-time tool wear identification using sensor integration ...

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IEEE Conference on Decision and Control

作者： N. Levy MengChu Zhou Yu Quan Department of Mechanical and Industrical Engineering New Jersey Institute of Technology Newark NJ USA Department of Electrical and Computer Engineering New Jersey Institute of Technology Newark NJ USA Manufacturing Engineering Program New Jersey Institute of Technology Newark NJ USA

Real-time identification of tool wear in shop floor environment is essential for optimization of machining processes and implementation of automated manufacturing systems. In this paper. the signals obtained from acoustic emission and power sensors during machining processes are analyzed and a set of feature parameters characterizing the tool wear condition are extracted. In order to realize the realtime tool wear condition monitoring for different cutting conditions, a sensor integration strategy which combines the information from multiple sensors (acoustic emission sensor and power sensor) and machining parameters is proposed. A neural network based on improved back-propogation algorithm is developed and a prototype scheme for realtime identification of tool wear is implemented. Experiments under different conditions have proved that a higher rate of tool wear identification can be achieved by using the sensor integration model with neural network. The results also indicated that the neural network is a very effective method of sensor integration for online monitoring of tool abnormalities.< >

关键词： Wearable sensors Sensor phenomena and characterization Acoustic sensors Machining Neural networks Acoustic emission Real time systems manufacturing systems Signal processing Signal analysis

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RESIN TRANSFER MOLDING WITH POWDER-COATED PREFORMS

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POLYMER COMPOSITES 1993年第4期14卷 341-348页

作者： SHIELDS, K COLTON, J Composites Manufacturing Research Program The George W. Woodruff School of Mechanical Engineering Georgia Institute of Technology Atlanta Georgia 30332‐0405

Incomplete fiber wetting in a resin transfer molded composite may result in poor surface finish, high void content, and reduced mechanical properties. This work studied the use of tows that are precoated with a powdered version of the liquid molding resin (towpregs). The goal is to see if such preforms improve the final part properties because of better fiber wetting. Hercules 12K AS-4 fibers and PR500 (liquid) and PS500 (powder) resins (3M) were used to make fabrics from towpregs containing 50 wt% total resin (liquid and powder combined). The powder fractions were 0, 13, 21, 50 wt%. Samples were resin transfer molded from preforms made from the towpreg fabrics. Results showed that samples molded with powder-coated preforms had improved surface finishes and reduced void contents (1.4 vs. 5%), but that the mechanical properties were not improved (transverse moduli of approximately 7.8 GPa and axial moduli of approximately 100 GPa), probably because of defects inherent in the hand-woven towpreg fabric that was used.

关键词： Transfer molding

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PROCESSING PARAMETERS FOR FILAMENT WINDING THICK-SECTION PEEK CARBON-FIBER COMPOSITES

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POLYMER COMPOSITES 1992年第6期13卷 427-434页

作者： COLTON, J LEACH, D Composites Manufacturing Research Program George W. Woodruff School of Mechanical Engineering Georgia Institute of Technology Atlanta Georgia 30332-0405

The consolidation pressure and winding speed for thermoplastic filament winding were studied. Thermoplastic composite parts were manufactured from tape prepreg (APC-2);powder-coated, semi-consolidated towpreg;and commingled fiber towpreg. The material used was carbon fiber (AS-4) (60 vol%) in a PEEK matrix. The parts made were open-ended cylinders of the three materials, 177.8-mm ID, 228.6 mm long, 17 plies thick with a 0-degrees lay-up angle;and rings, 50 plies of APC-2 thick, 6.35 mm wide (one strip wide), 177.8-mm ID, and a lay-up of 0-degrees. Their quality was determined by surface finish and void percentage. The tubes made from APC-2 appeared to have the best quality of the three prepregs. For the rings, the speed of lay-down had a significant effect (at a 99% confidence level) on both the final width of the parts and on the percentage of voids. The pressure of the roller had a significant effect on the final widths at a 99% confidence level, but a significant effect on the percentage of voids at only a 95% confidence level.

关键词： Composite materials

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Advanced Path Generator for Sculptured Surface Machining

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IFAC Proceedings Volumes 1992年第29期25卷 25-30页

作者： P.E. Orban National Research Council of Canada Advanced Manufacturing Technology Program Institute for Mechanical Engineering Ottawa K1A 0R6 Ontario Canada

In the paper a new path generator for sculptured surface machining is proposed. First the task distribution in the free-form shaped part production is analyzed. Existing mathematical methods for surface description are summarized, and the 3- and 5-axis tool path generation is reviewed The state of the art in sculptured surface machining is assessed, and the initial results of an advanced path generator are presented. Finally the future work is outlined.

关键词： computer numerical control interpolator sculptured surface machining tool path generation

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Data Point Reduction for NC Tool Path Generation on Over-Determined Data Set

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IFAC Proceedings Volumes 1992年第7期25卷 117-122页

作者： M. Yeung D. Walton Advanced Manufacturing Technology Program Institute of Mechanical Engineering National Research Council of Canada 435 Ellice Avenue Winnipeg Manitoba Canada R3B 1Y6 Department of Computer Science University of Manitoba Winnipeg Manitoba Canada R3T 2N2

Data acquired for object reproduction by laser or stereovision scanning processes are often over-determined. This causes problems in manufacturing processes, for example, NC tool path generation. Data reduction is a sensible solution to such problems. A heuristic method to reduce the data points with the user given tolerance is presented.

关键词： Data point reduction two axis scanner three axis scanner CNC tool path

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CAD CAM GOES TO SEA - THE SAAR-5 DESIGN AND CONSTRUCTION

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NAVAL ENGINEERS JOURNAL 1992年第3期104卷 148-155页

作者： LINDGREN, JR SOLITARIO, WA MOORE, AP STREIFF, MA John R. Lindgren Jr:. is vice president for engineering at Ingalls Shipbuilding Inc. a Division of Litton Industries in Pascagoula Miss. He joined Ingalls in 1958 and has held various positions in the Engineering Division and participated in the design of numerous merchant ships drill rigs submarines and surface combatants and auxiliary support ships. Mr. Lindgren is a 1958 graduate of the University of Southwest Louisiana. His degree is in mechanical engineering and he is also a licensed professional engineer. William A. Solitario:is the director of advanced technology at Ingalls Shipbuilding Inc. in Pascagoula Miss. He received his B.S. degree in chemical engineering from the City University of New York and has 28 years experience in marine engineering and design. His current responsibilities include the direction of Ingalls' IRAD programs and several Navy-funded R&D programs to improve ship's performance and reduce ship's operating costs. He is a member of the Society of Naval Architects and Marine Engineers and past chairman of the Gulf Section East Area. Arnold P. Moore:is the director design engineering at Ingalls Shipbuilding where he is responsible for all new construction design and engineering activities. Prior to promotion to his current position Mr. Moore served as chief naval architect at Ingalls. He has 24 years experience in ship design construction and repair. Mr. Moore holds the professional degree of ocean engineer as well as a master's degree in naval architecture and marine engineering from MIT. He also earned a bachelor's degree in naval science from the U.S. Naval Academy and is a registered professional engineer. Mr. Moore served as an engineering duty officer in the U.S. Navy and is currently a captain in the Naval Reserve. He is a past chairman of the Gulf Section of the Society of Naval Architects and Marine Engineers and a member of the American Society of Naval Engineers and Sigma Xi. Michel A. Streiff:is the manager of CAD/CAM applications at Ingalls Shipbuilding Inc. His

The SA'AR-5 Corvette program is the first major warship construction to be entirely accomplished using a 3-dimensional, interference checked computer based design. This paper discusses the organization and approach used to create the design models which form the basis for interference checking as well as the source of extracted production data. The design or product model is the nucleus of the computer data base that defines the configuration of the entire ship. The data base includes geometry, weight, and material, as well as production control data. The ability of the computer to link such diverse information is the key to maintaining configuration control during the course of the design and construction. The ease with which formatted manufacturing data (both N.C. fabrication and installation) can be extracted enables the preparation of detailed packages containing the desired geometry as well as the associated material and sequencing data, thus assuring the producibility of the design. The SA'AR-5 design is CAD/CAM's state of the art in U.S. shipbuilding.

关键词： Warships

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