The Experts below are selected from a list of 135 Experts worldwide ranked by ideXlab platform
Kristopher E. Wise - One of the best experts on this subject based on the ideXlab platform.
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Toward high performance thermoset/carbon nanotube Sheet nanocomposites via resistive Heating assisted infiltration and cure.
ACS Applied Materials & Interfaces, 2014Co-Authors: Godfrey Sauti, Russell A. Wincheski, Emilie J. Siochi, Joseph G. Smith, John W. Connell, Roberto J. Cano, Kristopher E. WiseAbstract:Thermoset/carbon nanotube (CNT) Sheet nanocomposites were successfully fabricated by resistive Heating assisted infiltration and cure (RHAIC) of the polymer matrix resin. Resistive Heating takes advantage of the electrical and thermal conductivity of CNTs to rapidly and uniformly introduce heat into the CNT Sheet. Heating the CNT Sheet reduces the viscosity of the polymer resin due to localized temperature rise in close proximity to the resin, which enhances resin flow, penetration, and wetting of the CNT reinforcement. Once the resin infusion process is complete, the applied power is increased to raise the temperature of the CNT Sheet, which rapidly cures the polymer matrix. Tensile tests were used to evaluate the mechanical properties of the processed thermoset/CNT Sheet nanocomposites. The improved wetting and adhesion of the polymer resin to the CNT reinforcement yield significant improvement of thermoset/CNT nanocomposite mechanical properties. The highest specific tensile strength of bismaleimide(BM...
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Toward high performance thermoset/carbon nanotube Sheet nanocomposites via resistive Heating assisted infiltration and cure
ACS Applied Materials and Interfaces, 2014Co-Authors: Jae-woo Kim, Russell A. Wincheski, Godfrey Sauti, Emilie J. Siochi, Joseph G. Smith, John W. Connell, Roberto J. Cano, Kristopher E. WiseAbstract:© 2014 American Chemical Society. Thermoset/carbon nanotube (CNT) Sheet nanocomposites were successfully fabricated by resistive Heating assisted infiltration and cure (RHAIC) of the polymer matrix resin. Resistive Heating takes advantage of the electrical and thermal conductivity of CNTs to rapidly and uniformly introduce heat into the CNT Sheet. Heating the CNT Sheet reduces the viscosity of the polymer resin due to localized temperature rise in close proximity to the resin, which enhances resin flow, penetration, and wetting of the CNT reinforcement. Once the resin infusion process is complete, the applied power is increased to raise the temperature of the CNT Sheet, which rapidly cures the polymer matrix. Tensile tests were used to evaluate the mechanical properties of t he processed thermoset/CNT Sheet nanocomposites. The improved wetting and adhesion of the polymer resin to the CNT reinforcement yield significant improvement of thermoset/CNT nanocomposite mechanical properties. The highest specific tensile strength of bismaleimide(BMI)/CNT Sheet nanocomposites was obtained to date was 684 MPa/(g/cm 3 ), using 4 V (2 A) for resin infiltration, followed by precure at 10 V (6 A) for 10 min and post curing at 240 °C for 6 h in an oven. The highest specific Young's modulus of BMI/CNT Sheet nanocomposite was 71 GPa/(g/cm 3 ) using resistive Heating infiltration at 8.3 V (4.7 A) for 3 min followed by resistive Heating cure at 12.5 V (7 A) for 30 min. In both cases, the CNT Sheets were stretched and held in tension to prevent relaxation of the aligned CNTs during the course of RHAIC.
José A. Covas - One of the best experts on this subject based on the ideXlab platform.
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Infrared Sheet Heating in roll fed thermoforming: Part 2 - Factors influencing inverse Heating solution
Plastics Rubber and Composites, 2013Co-Authors: F. M. Duarte, José A. CovasAbstract:Two methodologies for solving the inverse Heating problem in thermoforming, i.e. setting the temperature of the heaters that provide a prescribed temperature of the Sheet to be formed against the mould, are compared in terms of temperature gradients across the thickness and sensitivity to the most important process parameters. The influences of Sheet thickness, Sheet emissivity, room temperature, and distance between the heater bank and the forming station on the thermal homogeneity of the Sheet are also discussed.
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A computational study on the influence of the rheological behavior of polystyrene and its blends on their thermoforming ability
Journal of Polymer Engineering, 2005Co-Authors: F. M. Duarte, Vitor C. Barroso, Joao Maia, José A. CovasAbstract:The present work aims at understanding the relationship between Heating conditions, rheological behavior and thickness distribution that lead to the optimization of the latter in thermoforming. The materials used in this study were polystyrene, PS, high-impact polystyrene, HIPS, and a 50/50 w/w % blend of the two. The study was done by investigating computationally the influence of the material thermo-rheological properties on Sheet temperature and final thickness distribution of a vacuum-produced part and relating the Sheet Heating conditions with the forming stage. When Sheet temperature is uniform, the degree of strain hardening and the failure behavior in extension are the most important parameters in controlling the kinetics of the process and the thickness profile. In the case of nonuniform Sheet temperature, the results show that an increased degree of strain-hardening is more relevant to the dynamics of the process than relatively small differences in Sheet temperature. However, the solution of the inverse thermoforming problem (determining the heater temperature that induces a certain thickness distribution) showed that under practical processing conditions the effect of differences in thermal properties are predominant over the rheological ones.
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IR Sheet Heating in roll fed thermoforming: Part 1 - Solving direct and inverse Heating problems
Plastics Rubber and Composites, 2002Co-Authors: F. M. Duarte, José A. CovasAbstract:Computational methods for modelling the Heating stage in thermoforming of roll fed plastic Sheet (direct problem) and for setting the temperatures of the heater bank to produce a prescribed Sheet temperature (inverse problem) are presented, discussed, and experimentally validated. The algorithm computes the relevant local shape factors, and takes into account the effects of sag and of the surrounding air. The importance of some boundary conditions, such as air temperature, is discussed and quantitatively estimated.
Jae-woo Kim - One of the best experts on this subject based on the ideXlab platform.
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Toward high performance thermoset/carbon nanotube Sheet nanocomposites via resistive Heating assisted infiltration and cure
ACS Applied Materials and Interfaces, 2014Co-Authors: Jae-woo Kim, Russell A. Wincheski, Godfrey Sauti, Emilie J. Siochi, Joseph G. Smith, John W. Connell, Roberto J. Cano, Kristopher E. WiseAbstract:© 2014 American Chemical Society. Thermoset/carbon nanotube (CNT) Sheet nanocomposites were successfully fabricated by resistive Heating assisted infiltration and cure (RHAIC) of the polymer matrix resin. Resistive Heating takes advantage of the electrical and thermal conductivity of CNTs to rapidly and uniformly introduce heat into the CNT Sheet. Heating the CNT Sheet reduces the viscosity of the polymer resin due to localized temperature rise in close proximity to the resin, which enhances resin flow, penetration, and wetting of the CNT reinforcement. Once the resin infusion process is complete, the applied power is increased to raise the temperature of the CNT Sheet, which rapidly cures the polymer matrix. Tensile tests were used to evaluate the mechanical properties of t he processed thermoset/CNT Sheet nanocomposites. The improved wetting and adhesion of the polymer resin to the CNT reinforcement yield significant improvement of thermoset/CNT nanocomposite mechanical properties. The highest specific tensile strength of bismaleimide(BMI)/CNT Sheet nanocomposites was obtained to date was 684 MPa/(g/cm 3 ), using 4 V (2 A) for resin infiltration, followed by precure at 10 V (6 A) for 10 min and post curing at 240 °C for 6 h in an oven. The highest specific Young's modulus of BMI/CNT Sheet nanocomposite was 71 GPa/(g/cm 3 ) using resistive Heating infiltration at 8.3 V (4.7 A) for 3 min followed by resistive Heating cure at 12.5 V (7 A) for 30 min. In both cases, the CNT Sheets were stretched and held in tension to prevent relaxation of the aligned CNTs during the course of RHAIC.
Godfrey Sauti - One of the best experts on this subject based on the ideXlab platform.
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Toward high performance thermoset/carbon nanotube Sheet nanocomposites via resistive Heating assisted infiltration and cure.
ACS Applied Materials & Interfaces, 2014Co-Authors: Godfrey Sauti, Russell A. Wincheski, Emilie J. Siochi, Joseph G. Smith, John W. Connell, Roberto J. Cano, Kristopher E. WiseAbstract:Thermoset/carbon nanotube (CNT) Sheet nanocomposites were successfully fabricated by resistive Heating assisted infiltration and cure (RHAIC) of the polymer matrix resin. Resistive Heating takes advantage of the electrical and thermal conductivity of CNTs to rapidly and uniformly introduce heat into the CNT Sheet. Heating the CNT Sheet reduces the viscosity of the polymer resin due to localized temperature rise in close proximity to the resin, which enhances resin flow, penetration, and wetting of the CNT reinforcement. Once the resin infusion process is complete, the applied power is increased to raise the temperature of the CNT Sheet, which rapidly cures the polymer matrix. Tensile tests were used to evaluate the mechanical properties of the processed thermoset/CNT Sheet nanocomposites. The improved wetting and adhesion of the polymer resin to the CNT reinforcement yield significant improvement of thermoset/CNT nanocomposite mechanical properties. The highest specific tensile strength of bismaleimide(BM...
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Toward high performance thermoset/carbon nanotube Sheet nanocomposites via resistive Heating assisted infiltration and cure
ACS Applied Materials and Interfaces, 2014Co-Authors: Jae-woo Kim, Russell A. Wincheski, Godfrey Sauti, Emilie J. Siochi, Joseph G. Smith, John W. Connell, Roberto J. Cano, Kristopher E. WiseAbstract:© 2014 American Chemical Society. Thermoset/carbon nanotube (CNT) Sheet nanocomposites were successfully fabricated by resistive Heating assisted infiltration and cure (RHAIC) of the polymer matrix resin. Resistive Heating takes advantage of the electrical and thermal conductivity of CNTs to rapidly and uniformly introduce heat into the CNT Sheet. Heating the CNT Sheet reduces the viscosity of the polymer resin due to localized temperature rise in close proximity to the resin, which enhances resin flow, penetration, and wetting of the CNT reinforcement. Once the resin infusion process is complete, the applied power is increased to raise the temperature of the CNT Sheet, which rapidly cures the polymer matrix. Tensile tests were used to evaluate the mechanical properties of t he processed thermoset/CNT Sheet nanocomposites. The improved wetting and adhesion of the polymer resin to the CNT reinforcement yield significant improvement of thermoset/CNT nanocomposite mechanical properties. The highest specific tensile strength of bismaleimide(BMI)/CNT Sheet nanocomposites was obtained to date was 684 MPa/(g/cm 3 ), using 4 V (2 A) for resin infiltration, followed by precure at 10 V (6 A) for 10 min and post curing at 240 °C for 6 h in an oven. The highest specific Young's modulus of BMI/CNT Sheet nanocomposite was 71 GPa/(g/cm 3 ) using resistive Heating infiltration at 8.3 V (4.7 A) for 3 min followed by resistive Heating cure at 12.5 V (7 A) for 30 min. In both cases, the CNT Sheets were stretched and held in tension to prevent relaxation of the aligned CNTs during the course of RHAIC.
T. Pieja - One of the best experts on this subject based on the ideXlab platform.
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Warm forming of stainless steel Sheet
Archives of Civil and Mechanical Engineering, 2012Co-Authors: Feliks Stachowicz, T. Trzepieciński, T. PiejaAbstract:The aim of warm Sheet metal forming processes is to improve plastic flow of material, as well as to decrease the springback effect. This investigation deals with the effect of temperature in the range from 20 °C to 700 °C on basic material parameters of stainless steel Sheet metal such as yield stress, ultimate strength, total and uniform elongation, strain hardening parameters and plastic anisotropy factor. The results of carried out investigations will be useful for deep drawing processes preparation and modification, especially considering proper forming temperature. It was determined that the most suitable temperature of warm forming of the AMS 5604 stainless steel Sheet is 500 °C. Examination of the influence of the temperature, Sheet thickness and material Heating method (only Sheet Heating, Sheet and forming die Heating, isothermal conditions) on springback quantity was performed in air bending test. The MSC Marc Mentat commercial computer code was used for numerical simulation of analyzed forming processes.
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Warm forming of stainless steel Sheet
Archives of Civil and Mechanical Engineering, 2010Co-Authors: Feliks Stachowicz, T. Trzepieciński, T. PiejaAbstract:Celem procesów plastycznego kształtowania blach na półgorąco jest zwiększenie możliwości plastycznego płynięcia materiału, jak również zmniejszenie wartości powrotnych odkształceń sprężystych. Prezentowane wyniki badań dotyczą wpływu temperatury rozciągania próbek z zakresu 20 °C do 700 °C na wartość podstawowych parametrów mechanicznych blachy ze stali odpornej na korozję, takich jak: granica plastyczności, granica wytrzymałości, wydłużenie równomierne, wydłużenie całkowite, parametry krzywej umocnienia odkształceniowego, współczynnik anizotropii plastycznej. Uzyskane wyniki mogą być przydatne do opracowywania oraz modernizacji procesów plastycznego kształtowania blach, zwłaszcza w zakresie doboru temperatury kształtowania. Określono, że najbardziej odpowiednią temperaturą kształtowania na półgorąco blach ze stali odpornej na korozję AMS 5604 jest temperatura 500 °C. Ocenę wpływu temperatury kształtowania, grubości blachy oraz sposobu nagrzewania (nagrzewana tylko blacha, nagrzewana blacha oraz podgrzewane narzędzia, nagrzewanie izotermiczne w przestrzeni zamkniętej) na wartość powrotnych odkształceń sprężystych przeprowadzono w próbie gięcia swobodnego. Przeprowadzone zostało modelowanie numeryczne analizowanego procesu gięcia przy wykorzystaniu oprogramowania MSC Marc Mentat. The aim of warm Sheet metal forming processes is to improve plastic flow of material, as well as to decrease the springback effect. This investigation deals with the effect of temperature in the range from 20 °C to 700 °C on basic material parameters of stainless steel Sheet metal such as yield stress, ultimate strength, total and uniform elongation, strain hardening parameters and plastic anisotropy factor. The results of carried out investigations will be useful for deep drawing processes preparation and modification, especially considering proper forming temperature. It was determined that the most suitable temperature of warm forming of the AMS 5604 stainless steel Sheet is 500 °C. Examination of the influence of the temperature, Sheet thickness and material Heating method (only Sheet Heating, Sheet and forming die Heating, isothermal conditions) on springback quantity was performed in air bending test. The MSC Marc Mentat commercial computer code was used for numerical simulation of analyzed forming processes.