The Experts below are selected from a list of 243 Experts worldwide ranked by ideXlab platform

Ralf Schledjewski - One of the best experts on this subject based on the ideXlab platform.

  • Automated Tape Laying (ATL) process simulation through 3D thermo-mechanical model
    ECCM 2016 - Proceeding of the 17th European Conference on Composite Materials, 2016
    Co-Authors: Y. Duplessis Kergomard, B. Satheesh, Laetitia Dufort, Ralf Schledjewski
    Abstract:

    © 2016, European Conference on Composite Materials, ECCM. All rights reserved. The present paper describes the current state of work done during the STELLAR project on the ATP/ATL simulation. To assess the welding quality of the thermoplastic Tapes, the computation of the contact pressure, the temperature and the phase evolution in the matrix (evolution the degree of crystallinity) are first importance. In the present paper, a two steps approach is described to simulate the process, and we especially focus on the temperature field history assessment. In the first step, the heating flux boundary conditions imposed by a laser to the Tape, the head-tool and the support is assessed thanks to a ray tracing model. Then these heating boundary conditions are used in an explicit approach to solve the 3D thermo-mechanical problem.

  • 3D thermo-mechanical model based simulation of the welding of thermoplastic composite Tape using Automated Tape Laying (ATL) process
    ICCM International Conferences on Composite Materials, 2015
    Co-Authors: Y.d. Kergomard, B. Satheesh, Laetitia Dufort, Ralf Schledjewski
    Abstract:

    © 2015 International Committee on Composite Materials. All rights reserved. The present paper describes the current state of works done during the STELLAR project about the ATP simulation. To assess the welding quality of the thermoplastic taps, the computations of the contact pressure, the temperature and the phase evolution in the matrix (evolution the degree of crystallinity) are in first importance. In the present paper, we describes two approaches to solve the 3D thermo-mechanical problem: the first one corresponds to a steady state assumption solved with an implicit scheme and the second one corresponds to the dynamical problem taking into account of the kinematic of the tool, and solved with an explicit scheme.

Klaus Drechsler - One of the best experts on this subject based on the ideXlab platform.

  • Evaluating the potential of forming spot-welded layups out of fibre reinforced thermoplastic Tape without previous consolidation
    International Journal of Material Forming, 2019
    Co-Authors: Alexander Schug, Dennis Rinker, Roland Hinterhoelzl, Klaus Drechsler
    Abstract:

    With an Automated Tape Laying machine like the Fiberforge RELAY2000, spot-welded 2D layups of unidirectional fibre reinforced thermoplastic Tape can be produced within short time. The layup process is usually followed by a consolidation step to remove the air of the layup and to fuse the plies. After this, the preforms can be formed into 3D parts. As the consolidation step is very time and energy consuming, methods were investigated within this study to form carbon fibre reinforced polyamide 6 layups without any previous consolidation. A variety of challenges during pre-heating, handling and forming may occur. To cope with this, a number of different approaches were compared in terms of processability and resulting part quality: 1. Additional ultrasonic spot-welds to improve the heating in an infrared oven. 2. Vacuum setup with polyimide films to remove air and improve the heat transfer between the plies. 3. Vacuum setup with polyamide 6 films with the same aims as with the polyimide foil plus an improved formability. The quality of the formed parts was examined using thermography, microsections, void content and fibre volume fraction measurements. The reference were formed parts made of consolidated preforms. The evaluation revealed that the vacuum setup with polyamide 6 films generated the best results that were also comparable to the reference. The additional matrix material caused a reduction of fibre volume fraction and an increase in thickness, but also enabled new possibilities for joining with other parts.

  • Evaluating the potential of forming spot-welded layups out of fibre reinforced thermoplastic Tape without previous consolidation
    International Journal of Material Forming, 2019
    Co-Authors: Alexander Schug, Dennis Rinker, Roland Hinterhoelzl, Klaus Drechsler
    Abstract:

    © 2018 Springer-Verlag France SAS, part of Springer Nature With an Automated Tape Laying machine like the Fiberforge RELAY2000, spot-welded 2D layups of unidirectional fibre reinforced thermoplastic Tape can be produced within short time. The layup process is usually followed by a consolidation step to remove the air of the layup and to fuse the plies. After this, the preforms can be formed into 3D parts. As the consolidation step is very time and energy consuming, methods were investigated within this study to form carbon fibre reinforced polyamide 6 layups without any previous consolidation. A variety of challenges during pre-heating, handling and forming may occur. To cope with this, a number of different approaches were compared in terms of processability and resulting part quality: 1. Additional ultrasonic spot-welds to improve the heating in an infrared oven. 2. Vacuum setup with polyimide films to remove air and improve the heat transfer between the plies. 3. Vacuum setup with polyamide 6 films with the same aims as with the polyimide foil plus an improved formability. The quality of the formed parts was examined using thermography, microsections, void content and fibre volume fraction measurements. The reference were formed parts made of consolidated preforms. The evaluation revealed that the vacuum setup with polyamide 6 films generated the best results that were also comparable to the reference. The additional matrix material caused a reduction of fibre volume fraction and an increase in thickness, but also enabled new possibilities for joining with other parts.

  • Thermoforming of glass fibre reinforced polypropylene: A study on the influence of different process parameters
    2017
    Co-Authors: Alexander Schug, Jonas Winkelbauer, Roland Hinterhölzl, Klaus Drechsler
    Abstract:

    The aim of this study was to analyse the forming behaviour of glass fibre reinforced polypropylene and to identify the influence of several process parameters on the resulting part quality. For this purpose, a complex forming tool was designed, consisting of several areas with single and double curvature. The specimens were produced from unidirectional (UD) Tape using the Fiberforge RELAY2000® Automated Tape Laying machine and a subsequent consolidation step. They were then fixed in a support frame, pre-heated in an infrared oven, and formed in the forming tool, which was mounted into a hydraulic heating press. The investigated process parameters were the number and force of the springs in the support frame, the tool temperature and the forming pressure and speed. The layups of the specimens were [0/90/0/90/0]s and [0/45/90/-45/0]s. After the forming process, the parts were analysed in terms of their quality, with a special focus on wrinkles, undulations, gaps and surface roughness. In addition to optic...

  • Thermoforming of glass fibre reinforced polypropylene: A study on the influence of different process parameters
    AIP Conference Proceedings, 2017
    Co-Authors: Alexander Schug, Jonas Winkelbauer, Roland Hinterhölzl, Klaus Drechsler
    Abstract:

    © 2017 Author(s). The aim of this study was to analyse the forming behaviour of glass fibre reinforced polypropylene and to identify the influence of several process parameters on the resulting part quality. For this purpose, a complex forming tool was designed, consisting of several areas with single and double curvature. The specimens were produced from unidirectional (UD) Tape using the Fiberforge RELAY2000® Automated Tape Laying machine and a subsequent consolidation step. They were then fixed in a support frame, pre-heated in an infrared oven, and formed in the forming tool, which was mounted into a hydraulic heating press. The investigated process parameters were the number and force of the springs in the support frame, the tool temperature and the forming pressure and speed. The layups of the specimens were [0/90/0/90/0]s and [0/45/90/-45/0] s. After the forming process, the parts were analysed in terms of their quality, with a special focus on wrinkles, undulations, gaps and surface roughness. In addition to optical analysis with a statistical evaluation of the results, 3D scans of the specimens at different steps of the forming process were made to gain an impression of the forming mechanisms and the development of failures. The ATOS system of GOM was used for these 3D scans. The results show that the undulations were influenced by the tool temperature and the spring force. By contrast, the surface quality was most strongly dependent on the forming pressure, which also influenced the size and the number of gaps. The forming speed affected the gaps as well. The tool temperature had the largest influence on the development of wrinkles. As expected, the quasi-isotropic layup showed distinctly more wrinkles and undulations, but it also presented a better surface quality than the orthotropic layup.

Y.d. Kergomard - One of the best experts on this subject based on the ideXlab platform.

  • 3D thermo-mechanical model based simulation of the welding of thermoplastic composite Tape using Automated Tape Laying (ATL) process
    ICCM International Conferences on Composite Materials, 2015
    Co-Authors: Y.d. Kergomard, B. Satheesh, Laetitia Dufort, Ralf Schledjewski
    Abstract:

    © 2015 International Committee on Composite Materials. All rights reserved. The present paper describes the current state of works done during the STELLAR project about the ATP simulation. To assess the welding quality of the thermoplastic taps, the computations of the contact pressure, the temperature and the phase evolution in the matrix (evolution the degree of crystallinity) are in first importance. In the present paper, we describes two approaches to solve the 3D thermo-mechanical problem: the first one corresponds to a steady state assumption solved with an implicit scheme and the second one corresponds to the dynamical problem taking into account of the kinematic of the tool, and solved with an explicit scheme.

Alexander Schug - One of the best experts on this subject based on the ideXlab platform.

  • Evaluating the potential of forming spot-welded layups out of fibre reinforced thermoplastic Tape without previous consolidation
    International Journal of Material Forming, 2019
    Co-Authors: Alexander Schug, Dennis Rinker, Roland Hinterhoelzl, Klaus Drechsler
    Abstract:

    With an Automated Tape Laying machine like the Fiberforge RELAY2000, spot-welded 2D layups of unidirectional fibre reinforced thermoplastic Tape can be produced within short time. The layup process is usually followed by a consolidation step to remove the air of the layup and to fuse the plies. After this, the preforms can be formed into 3D parts. As the consolidation step is very time and energy consuming, methods were investigated within this study to form carbon fibre reinforced polyamide 6 layups without any previous consolidation. A variety of challenges during pre-heating, handling and forming may occur. To cope with this, a number of different approaches were compared in terms of processability and resulting part quality: 1. Additional ultrasonic spot-welds to improve the heating in an infrared oven. 2. Vacuum setup with polyimide films to remove air and improve the heat transfer between the plies. 3. Vacuum setup with polyamide 6 films with the same aims as with the polyimide foil plus an improved formability. The quality of the formed parts was examined using thermography, microsections, void content and fibre volume fraction measurements. The reference were formed parts made of consolidated preforms. The evaluation revealed that the vacuum setup with polyamide 6 films generated the best results that were also comparable to the reference. The additional matrix material caused a reduction of fibre volume fraction and an increase in thickness, but also enabled new possibilities for joining with other parts.

  • Evaluating the potential of forming spot-welded layups out of fibre reinforced thermoplastic Tape without previous consolidation
    International Journal of Material Forming, 2019
    Co-Authors: Alexander Schug, Dennis Rinker, Roland Hinterhoelzl, Klaus Drechsler
    Abstract:

    © 2018 Springer-Verlag France SAS, part of Springer Nature With an Automated Tape Laying machine like the Fiberforge RELAY2000, spot-welded 2D layups of unidirectional fibre reinforced thermoplastic Tape can be produced within short time. The layup process is usually followed by a consolidation step to remove the air of the layup and to fuse the plies. After this, the preforms can be formed into 3D parts. As the consolidation step is very time and energy consuming, methods were investigated within this study to form carbon fibre reinforced polyamide 6 layups without any previous consolidation. A variety of challenges during pre-heating, handling and forming may occur. To cope with this, a number of different approaches were compared in terms of processability and resulting part quality: 1. Additional ultrasonic spot-welds to improve the heating in an infrared oven. 2. Vacuum setup with polyimide films to remove air and improve the heat transfer between the plies. 3. Vacuum setup with polyamide 6 films with the same aims as with the polyimide foil plus an improved formability. The quality of the formed parts was examined using thermography, microsections, void content and fibre volume fraction measurements. The reference were formed parts made of consolidated preforms. The evaluation revealed that the vacuum setup with polyamide 6 films generated the best results that were also comparable to the reference. The additional matrix material caused a reduction of fibre volume fraction and an increase in thickness, but also enabled new possibilities for joining with other parts.

  • Thermoforming of glass fibre reinforced polypropylene: A study on the influence of different process parameters
    2017
    Co-Authors: Alexander Schug, Jonas Winkelbauer, Roland Hinterhölzl, Klaus Drechsler
    Abstract:

    The aim of this study was to analyse the forming behaviour of glass fibre reinforced polypropylene and to identify the influence of several process parameters on the resulting part quality. For this purpose, a complex forming tool was designed, consisting of several areas with single and double curvature. The specimens were produced from unidirectional (UD) Tape using the Fiberforge RELAY2000® Automated Tape Laying machine and a subsequent consolidation step. They were then fixed in a support frame, pre-heated in an infrared oven, and formed in the forming tool, which was mounted into a hydraulic heating press. The investigated process parameters were the number and force of the springs in the support frame, the tool temperature and the forming pressure and speed. The layups of the specimens were [0/90/0/90/0]s and [0/45/90/-45/0]s. After the forming process, the parts were analysed in terms of their quality, with a special focus on wrinkles, undulations, gaps and surface roughness. In addition to optic...

  • Thermoforming of glass fibre reinforced polypropylene: A study on the influence of different process parameters
    AIP Conference Proceedings, 2017
    Co-Authors: Alexander Schug, Jonas Winkelbauer, Roland Hinterhölzl, Klaus Drechsler
    Abstract:

    © 2017 Author(s). The aim of this study was to analyse the forming behaviour of glass fibre reinforced polypropylene and to identify the influence of several process parameters on the resulting part quality. For this purpose, a complex forming tool was designed, consisting of several areas with single and double curvature. The specimens were produced from unidirectional (UD) Tape using the Fiberforge RELAY2000® Automated Tape Laying machine and a subsequent consolidation step. They were then fixed in a support frame, pre-heated in an infrared oven, and formed in the forming tool, which was mounted into a hydraulic heating press. The investigated process parameters were the number and force of the springs in the support frame, the tool temperature and the forming pressure and speed. The layups of the specimens were [0/90/0/90/0]s and [0/45/90/-45/0] s. After the forming process, the parts were analysed in terms of their quality, with a special focus on wrinkles, undulations, gaps and surface roughness. In addition to optical analysis with a statistical evaluation of the results, 3D scans of the specimens at different steps of the forming process were made to gain an impression of the forming mechanisms and the development of failures. The ATOS system of GOM was used for these 3D scans. The results show that the undulations were influenced by the tool temperature and the spring force. By contrast, the surface quality was most strongly dependent on the forming pressure, which also influenced the size and the number of gaps. The forming speed affected the gaps as well. The tool temperature had the largest influence on the development of wrinkles. As expected, the quasi-isotropic layup showed distinctly more wrinkles and undulations, but it also presented a better surface quality than the orthotropic layup.

Laetitia Dufort - One of the best experts on this subject based on the ideXlab platform.

  • Automated Tape Laying (ATL) process simulation through 3D thermo-mechanical model
    ECCM 2016 - Proceeding of the 17th European Conference on Composite Materials, 2016
    Co-Authors: Y. Duplessis Kergomard, B. Satheesh, Laetitia Dufort, Ralf Schledjewski
    Abstract:

    © 2016, European Conference on Composite Materials, ECCM. All rights reserved. The present paper describes the current state of work done during the STELLAR project on the ATP/ATL simulation. To assess the welding quality of the thermoplastic Tapes, the computation of the contact pressure, the temperature and the phase evolution in the matrix (evolution the degree of crystallinity) are first importance. In the present paper, a two steps approach is described to simulate the process, and we especially focus on the temperature field history assessment. In the first step, the heating flux boundary conditions imposed by a laser to the Tape, the head-tool and the support is assessed thanks to a ray tracing model. Then these heating boundary conditions are used in an explicit approach to solve the 3D thermo-mechanical problem.

  • 3D thermo-mechanical model based simulation of the welding of thermoplastic composite Tape using Automated Tape Laying (ATL) process
    ICCM International Conferences on Composite Materials, 2015
    Co-Authors: Y.d. Kergomard, B. Satheesh, Laetitia Dufort, Ralf Schledjewski
    Abstract:

    © 2015 International Committee on Composite Materials. All rights reserved. The present paper describes the current state of works done during the STELLAR project about the ATP simulation. To assess the welding quality of the thermoplastic taps, the computations of the contact pressure, the temperature and the phase evolution in the matrix (evolution the degree of crystallinity) are in first importance. In the present paper, we describes two approaches to solve the 3D thermo-mechanical problem: the first one corresponds to a steady state assumption solved with an implicit scheme and the second one corresponds to the dynamical problem taking into account of the kinematic of the tool, and solved with an explicit scheme.