Sustainable Integration Strategy for Recycled Carbon Fiber Nonwovens within CFRP Boss Structures for Pressure Vessels
Topic(s) : Material and Structural Behavior - Simulation & Testing
Co-authors :
Maximilian KORFF (GERMANY), Eduardo SZPOGANICZ (GERMANY), Georg STEGSCHUSTER (GERMANY), Fabian HÜBNER , Holger RUCKDÄSCHEL (GERMANY), Tobias DICKHUT (GERMANY)Abstract :
Due to the rising demand of carbon fibers, the need of finding applications for reused or recycled carbon fibers is becoming increasingly important. In particular, the processing of offcuts or pryolized components into a nonwoven is often investigated.
This presentation shows a possibility in the field of pressure tanks to use recycled carbon fiber nonwoven efficiently and sustainably in order to reduce the amount of new fibers used to the necessary minimum per component.
Despite of the high requirements on the material in carbon fiber reinforced pressure vessels, the fittings (endcaps/bosses) enable possibilities to integrate a significant amount of recycled material without reducing the design or performance capability. Conventionally, these are made of aluminum and therefore offer potential for weight reduction using aluminum. This integration of recycled and unidirectional (UD) material will be achieved with a structurally suitable combination of unidirectional carbon fibers in the outer parts of the boss and recycled carbon fiber nonwoven in the inner areas.
A structure comparable to a sandwich structure is thus created within the component, with the recycled material serving as a filler material on the inside, which is subject to less mechanical stress compared to the outer cover layers made of UD material.
Processing and infusion using the resin transfer molding (RTM) process ensures high material quality and basic suitability for industrial implementation. The feasibility of using recycled carbon fibers in CFRP fittings is shown with the help of a production demonstrator.
Furthermore, mechanical tests with RTM-samples are used to determine the stiffness and strength properties of the nonwoven in the machine direction (MD) of the carding machine and transversal to it, cross direction (CD), which are necessary for designing with finite element method (FEM). The fiber volume contents of the samples are also determined using the thermogravimetry and the RTM laminate is examined in micrographs in order to gain a deeper understanding of the behavior of carbon fiber nonwovens in the RTM process.
This shown concept, was developed by the University of the Bundeswehr Munich as part of the "INTAKT" research project in collaboration with the University of Bayreuth, Airbus Central Research and Technology and with material of the institute for textile technology Augsburg. It is supported by measurement data of the carbon fiber nonwoven, a manufacturing demonstrator as well as simulation data of the CFRP-Boss part to demonstrate the suitability of sandwich structures made from recycled carbon fibers and UD material.
This presentation shows a possibility in the field of pressure tanks to use recycled carbon fiber nonwoven efficiently and sustainably in order to reduce the amount of new fibers used to the necessary minimum per component.
Despite of the high requirements on the material in carbon fiber reinforced pressure vessels, the fittings (endcaps/bosses) enable possibilities to integrate a significant amount of recycled material without reducing the design or performance capability. Conventionally, these are made of aluminum and therefore offer potential for weight reduction using aluminum. This integration of recycled and unidirectional (UD) material will be achieved with a structurally suitable combination of unidirectional carbon fibers in the outer parts of the boss and recycled carbon fiber nonwoven in the inner areas.
A structure comparable to a sandwich structure is thus created within the component, with the recycled material serving as a filler material on the inside, which is subject to less mechanical stress compared to the outer cover layers made of UD material.
Processing and infusion using the resin transfer molding (RTM) process ensures high material quality and basic suitability for industrial implementation. The feasibility of using recycled carbon fibers in CFRP fittings is shown with the help of a production demonstrator.
Furthermore, mechanical tests with RTM-samples are used to determine the stiffness and strength properties of the nonwoven in the machine direction (MD) of the carding machine and transversal to it, cross direction (CD), which are necessary for designing with finite element method (FEM). The fiber volume contents of the samples are also determined using the thermogravimetry and the RTM laminate is examined in micrographs in order to gain a deeper understanding of the behavior of carbon fiber nonwovens in the RTM process.
This shown concept, was developed by the University of the Bundeswehr Munich as part of the "INTAKT" research project in collaboration with the University of Bayreuth, Airbus Central Research and Technology and with material of the institute for textile technology Augsburg. It is supported by measurement data of the carbon fiber nonwoven, a manufacturing demonstrator as well as simulation data of the CFRP-Boss part to demonstrate the suitability of sandwich structures made from recycled carbon fibers and UD material.