The Experts below are selected from a list of 3810 Experts worldwide ranked by ideXlab platform

Stephen Pickering - One of the best experts on this subject based on the ideXlab platform.

  • Wiley Encyclopedia of Composites - Recycling Thermoset Composite Materials
    Wiley Encyclopedia of Composites, 2012
    Co-Authors: Stephen Pickering
    Abstract:

    In this article, the recycling of Thermoset Composites is described. Thermosetting polymers, once cured, cannot be remolded by melting and so the methods used for recycling thermoplastics cannot be used. Recycling is therefore carried out by one of two methods. The waste Composite materials may be reduced in size to make powdered and fibrous materials that may be used as constituents in new Composites. Alternatively, thermal and chemical techniques are used to remove the Thermosetting polymer from the fiber reinforcement to produce a fiber recyclate, potentially of high value, that can be used as a reinforcement in new Composites. The current state of development of these recycling routes is described and applications for the recycled material considered. Some areas for future research are identified. Keywords: recycling; Composites; Thermosets; carbon fiber; glass fiber

  • Recycling technologies for Thermoset Composite materials—current status
    Composites Part A-applied Science and Manufacturing, 2006
    Co-Authors: Stephen Pickering
    Abstract:

    The technologies for recycling Thermoset Composite materials are reviewed. Mechanical recycling techniques involve the use of grinding techniques to comminute the scrap material and produce recyclate products in different size ranges suitable for reuse as fillers or partial reinforcement in new Composite material. Thermal recycling processes involve the use of heat to break the scrap Composite down and a range of processes are described in which there are various degrees of energy and material recovery. The prospects for commercially successful Composites recycling operations are considered and a new initiative within the European Composites industry to stimulate recycling is described.

Steve J. Pickering - One of the best experts on this subject based on the ideXlab platform.

  • recycling Thermoset Composite materials
    Wiley Encyclopedia of Composites, 2012
    Co-Authors: Steve J. Pickering
    Abstract:

    In this article, the recycling of Thermoset Composites is described. Thermosetting polymers, once cured, cannot be remolded by melting and so the methods used for recycling thermoplastics cannot be used. Recycling is therefore carried out by one of two methods. The waste Composite materials may be reduced in size to make powdered and fibrous materials that may be used as constituents in new Composites. Alternatively, thermal and chemical techniques are used to remove the Thermosetting polymer from the fiber reinforcement to produce a fiber recyclate, potentially of high value, that can be used as a reinforcement in new Composites. The current state of development of these recycling routes is described and applications for the recycled material considered. Some areas for future research are identified. Keywords: recycling; Composites; Thermosets; carbon fiber; glass fiber

  • recycling technologies for Thermoset Composite materials current status
    Composites Part A-applied Science and Manufacturing, 2006
    Co-Authors: Steve J. Pickering
    Abstract:

    The technologies for recycling Thermoset Composite materials are reviewed. Mechanical recycling techniques involve the use of grinding techniques to comminute the scrap material and produce recyclate products in different size ranges suitable for reuse as fillers or partial reinforcement in new Composite material. Thermal recycling processes involve the use of heat to break the scrap Composite down and a range of processes are described in which there are various degrees of energy and material recovery. The prospects for commercially successful Composites recycling operations are considered and a new initiative within the European Composites industry to stimulate recycling is described.

  • Recycling Technologies For Thermoset Composite Materials
    Advanced Polymer Composites for Structural Applications in Construction: ACIC 2004, 2004
    Co-Authors: Steve J. Pickering
    Abstract:

    The technologies for recycling Thermoset Composite materials are reviewed. Mechanical recycling techniques involve the use of grinding techniques to comminute the scrap material and produce recyclate products in different size ranges suitable for reuse as fillers or partial reinforcement in new Composite material. Thermal recycling processes involve the use of heat to break the scrap Composite down and a range of processes are described in which there are various degrees of energy and material recovery. The prospects for commercially successful Composites recycling operations are considered and a new initiative within the European Composites industry to stimulate recycling is described.

H. Teng - One of the best experts on this subject based on the ideXlab platform.

  • Analysis of fiber motion during wet filament winding of Composite cylinders with arbitrary thickness
    International Journal of Solids and Structures, 1992
    Co-Authors: A. Agah-tehrani, H. Teng
    Abstract:

    Abstract A continuum consolidation model is proposed for macroscopic analysis of fiber motion during filament winding of Thermoset Composite cylinders with arbitrary thickness. The model takes account of the variation of both instantaneous stiffness and permeability of the mixture with fiber compaction. Due to resin filtration, structure of the resulting initial-boundary value problem is similar to that of a moving boundary problem. Based on this analogy, a finite difference scheme is devised for the solution of the problem. For the case of winding onto a rigid mandrel, the results point to the existence of an active and a passive zone of consolidation. The results further indicate the possibility that during hoop winding of relatively thick cylinders, the tension can be completely lost in the portion of the passive zone away from the mandrel.

  • A Model for Wet Filament Winding of Composite Cylinders with Arbitrary Thickness
    1991
    Co-Authors: A. Agah-tehrani, H. Teng
    Abstract:

    Abstract : A continuum consolidation is purposed for analyzing the filament winding of Thermoset Composite cylinders with arbitrary thickness. The model takes account of the variation of both the instantaneous stiffness and the permeability of the mixture with fiber compaction. Due to resin filtration, the structure of the resulting initial-boundary value problem is similar to that of a moving boundary problem. Based on this analogy, a finite difference scheme is devised for the solution of the problem. For the case of winding onto a rigid mandrel, the results point to the existence of an active and a passive zone of consolidation. The results further indicate the possibility that during hoop winding of relatively thick cylinders, the tension can be completely lost in the portion of the passive zone away from the mandrel.

Boming Zhang - One of the best experts on this subject based on the ideXlab platform.

  • critical void content for Thermoset Composite laminates
    Journal of Composite Materials, 2009
    Co-Authors: Zhansheng Guo, Boming Zhang, Ling Liu, Shanyi Du
    Abstract:

    An experimental program to characterize the effect of voids on the strength of Composite laminates is presented. The adequacy of a fracture criterion to represent the experimental data for the effect of voids on the flexure strength, tensile strength, and interlaminar shear strength of Composite laminates is assessed. The experimental program investigates the effect of different pressures and dwell times on the critical void content. Laminates produced with carbon fiber/epoxy resin unidirectional prepreg have been produced with an intentionally high void content. Short beam shear, three-point flexure, and tensile testing are used for mechanical evaluation and the results correlate to void volume fraction and ultrasonic absorption coefficient. The ultrasonic absorption coefficient is measured for all the specimens and its variation is approximately linear with the void content, corroborating previous experimental results. The effects of these factors on the strength of the Composite laminates are discussed in terms of the fracture parameters involved in the fracture criterion. The critical void content is estimated for each case both in terms of void content and ultrasonic attenuation.

  • cure kinetics of t700 bmi prepreg used for advanced Thermoset Composite
    Journal of Applied Polymer Science, 2005
    Co-Authors: Zhansheng Guo, Boming Zhang
    Abstract:

    A new isothermally based, cure kinetic model for the prepreg was presented using an industrially supplied prepreg rather than pure resin. The matrix resin was bismaleimide (BMI) resins, and the reinforcement was carbon fiber T700–12S. The BMI prepreg was measured from 170 to 220°C by isothermal DSC. The isothermal cure reaction heat increases with the increment of cure temperature. The DSC data were analyzed by the proposed nth-order reaction model. An increase in reaction rate was observed at higher temperature in both neat and prepreg. After reaching the peak value, the reaction rate dropped off faster in prepreg, resulting in a lower average value of the ultimate heat of reaction. It was suggested the presence of carbon fiber had an effect on the cure kinetics as a heat sink. The carbon fibers imposed restrictions on the molecular mobility of the reactive species and did not change the cure mechanism. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 2238–2241, 2005

  • temperature field of thick Thermoset Composite laminates during cure process
    Composites Science and Technology, 2005
    Co-Authors: Shanyi Du, Boming Zhang
    Abstract:

    The development of temperature field of thick Thermoset matrix laminates manufactured by autoclave vacuum bag process were measured and compared with the numerically calculated results. The finite element formulation of the transient heat transfer problem was carried out for polymeric matrix Composite materials from the heat transfer differential equations including internal heat generation produced by exothermic chemical reactions. The finite element analysis software, which was based on the general finite element software package, was developed for numerical simulation of the entire Composite process. From the experimental and numerical results, it was found that the measured temperatures profiles were in good agreement with the numerical ones, and conventional cure cycles recommended by prepreg manufacturers for thin laminates should be modified to reduce out-of-plane temperature gradient.

Jaron Kuppers - One of the best experts on this subject based on the ideXlab platform.

  • thermal press curing of advanced Thermoset Composite laminate parts
    Composites Part A-applied Science and Manufacturing, 2012
    Co-Authors: Daniel F Walczyk, Jaron Kuppers
    Abstract:

    Abstract An alternative process to autoclaving, called Thermal Press Curing (TPC), is proposed, whereby an uncured Composite laminate is pressed between a heated curing mold and customized rubber-faced mold that are designed to provide uniform temperature and pressure conditions. TPC was demonstrated by designing a complex 3-D ‘benchmark’ part shape, applying a simple computational algorithm to derive the required tool shapes, and fabricating the tooling. A comparative study was performed involving the benchmark part made from four plies of woven carbon/epoxy prepreg material. Identical laminates were pre-formed by double diaphragm forming and then cured and consolidated by autoclaving, Quickstep, and TPC using standard industry practice. Results of the study indicate that the TPC part is of similar quality as compared to those made by autoclaving and Quickstep, but, more importantly, requiring significantly less energy and resource consumption, lower cost (capital and recurring), and less preparation and cycle time.

  • Curing and Consolidation of Advanced Thermoset Composite Laminate Parts by Pressing Between a Heated Mold and Customized Rubber-Faced Mold
    Journal of Manufacturing Science and Engineering, 2011
    Co-Authors: Daniel F Walczyk, Jaron Kuppers, Casey Hoffman
    Abstract:

    Curing and consolidating Thermoset Composite laminates and sandwich structures typically involves vacuum bagging an uncured and formed layup over a thin-walled mold, placing it in an autoclave, and subjecting the entire unit to temperature, vacuum, and pressure cycles as prescribed by the manufacturer. Autoclaving is generally considered the major bottleneck in manufacturing advanced Composite parts because of high capital and consumable costs, energy usage, waste generated, and process scalability. A new curing and consolidation process called "thermal press curing" is presented and demonstrated as an alternative to autoclaving. The process involves compressing a Composite laminate between a special mold set—a heated metal mold and a matching rubber-covered mold made of an insulative material—designed to provide uniform temperature and pressure over the metal mold surface, that is, mimic the process conditions provided by an autoclave. The thermal press curing process is demonstrated for the first time using a mold set for a simple two-dimensional axisymmetric shape. An aluminum curing mold with embedded electric resistance cartridge heaters is heuristically designed to provide uniform temperature in operation across the mold surface within 1°C of the target value (177°C). With the mold set compressing an eight-ply carbon/epoxy Composite workpiece and well insulated on all sides, the power draw is at least one to two orders of magnitude less than a comparable autoclaving operation. The potential to significantly improve pressure uniformity from the compressed rubber mask is shown by changing the mask shape. Even without an optimized rubber layer shape and thickness, the eight-ply Composite part was successfully cured. Finally, a plan for future work is described.

  • Curing and Consolidation of Advanced Thermoset Composite Laminate Parts by Pressing Between a Heated Mold and Customized Rubber-Faced Mold
    ASME 2010 International Manufacturing Science and Engineering Conference Volume 1, 2010
    Co-Authors: Daniel F Walczyk, Jaron Kuppers, Casey Hoffman
    Abstract:

    Curing and consolidating Thermoset Composite laminates and sandwich structures typically involves vacuum bagging an uncured and formed layup over a thin-walled mold, placing it in an autoclave, and subjecting the entire unit to temperature, vacuum and pressure cycles as prescribed by the manufacturer. Autoclaving is generally considered the major bottleneck in manufacturing of advanced Composites parts because of high capital and consumable costs, energy usage, waste generated and process scalability. A new curing and consolidation process, called ‘thermal press curing’ is discussed and demonstrated as an alternative to autoclaving. The process involves compressing a Composite laminate between a special mold set — heated metal mold and a matching rubber-covered mold made of an insulative material — designed to provide uniform temperature and pressure over the metal mold surface, that is, mimic the process conditions provided by an autoclave. The thermal press curing process is demonstrated for the first time using a mold set for a simple 2-dimensional axisymmetric shape. An aluminum curing mold with embedded electric resistance cartridge heaters is heuristically designed to provide uniform temperature in operation across the mold surface within 1°C of the target value (177°C). With the mold set compressing an eight-ply carbon/epoxy Composite workpiece and well insulated on all sides, the power draw is at least 1–2 orders-of-magnitude less than a comparable autoclaving operation. The potential to significantly improve pressure uniformity from the compressed rubber mask is shown by changing the mask shape. Even without an optimized rubber layer shape and thickness, the eight-ply Composite part was successfully cured. Finally, a plan for future work is described.Copyright © 2010 by ASME