Numerical simulation and experimental validation of a composite recycling process : from packing to consolidation.
Topic(s) : Special Sessions
Co-authors :
Awen BRUNEAU (FRANCE), Christophe BINETRUY (FRANCE), Sebastien COMAS-CARDONA (FRANCE), Charlotte LANDRY (FRANCE), Nelly DURAND (FRANCE)Abstract :
Continuous fibers reinforced composites are used in various fields and their production increased over the last few decades. They feature high strength to weight ratio. Thermoplastic composites (TPC) embody a promising recycling potential. In this context, CETIM developed a pilot line, including Thermosaïc® process, which aims at reusing production and end of life continuous fibers TPC wastes to manufacture new parts. The challenge is to understand and build a model to optimize the process in order to ensure sufficiently high mechanical properties for these parts made of recycled TPC from shredded or cut TPC.
Thermosaïc® technology was patented in 2016 by CETIM [1]. Composites flakes are transformed into plates ready to be stamped or machined . These flakes are the result of shredding or cutting steps on composite wastes. The flakes are deposited on a conveyor belt, which transports the random stack under two consecutive heating presses to consolidate the pile into a plate. For this study, it has been chosen to distinguish two consecutive steps: first, the deposition step, where the stack of shredded TPC is created and then, the compression step where the stack is transformed into consolidated plate. Due to the fiber length reduction occurring during the grinding or cutting step, this technology can be considered as a discontinuous fiber consolidation process. It aims at manufacturing parts with higher stiffness and strength than thermoplastic injection or short fiber compression.
The first step consists in building a stack from random size and number of composites flakes. Bullet Physics [2], a physics engine solver was used to simulate packing. This code allows to generate numerical objects and simulate their interactions. The generated objects are subjected to gravity, defined in the numerical environment, and the contacts between each object is simulated. In order to extract information of the stack and define its features, geometrical descriptors of the stack have been built from simulations. These descriptors allow to compare one stack to another and would help to evaluate which parameters of the stack will influence the quality of a consolidated plate at the end of the whole process. A stack made of a thousand flakes is shown in Fig.1. Once a stack is numerically built, each element is meshed and becomes the input configuration of a finite element simulation run with OpenRadioss [3]. Both solid and shell elements are investigated to fit the compression behavior of the flakes during consolidation. A first example of compressed flakes is given in Fig.2.
Each step of the process is replicated with lab scale configurations to access the material behavior during the process. A controlled deposition setup has been built to ensure reproducible deposition and fine tune the packing simulation. A tensile test machine is used with temperature-controlled plates to replicate the consolidation step and extract force and displacement evolutions.
Thermosaïc® technology was patented in 2016 by CETIM [1]. Composites flakes are transformed into plates ready to be stamped or machined . These flakes are the result of shredding or cutting steps on composite wastes. The flakes are deposited on a conveyor belt, which transports the random stack under two consecutive heating presses to consolidate the pile into a plate. For this study, it has been chosen to distinguish two consecutive steps: first, the deposition step, where the stack of shredded TPC is created and then, the compression step where the stack is transformed into consolidated plate. Due to the fiber length reduction occurring during the grinding or cutting step, this technology can be considered as a discontinuous fiber consolidation process. It aims at manufacturing parts with higher stiffness and strength than thermoplastic injection or short fiber compression.
The first step consists in building a stack from random size and number of composites flakes. Bullet Physics [2], a physics engine solver was used to simulate packing. This code allows to generate numerical objects and simulate their interactions. The generated objects are subjected to gravity, defined in the numerical environment, and the contacts between each object is simulated. In order to extract information of the stack and define its features, geometrical descriptors of the stack have been built from simulations. These descriptors allow to compare one stack to another and would help to evaluate which parameters of the stack will influence the quality of a consolidated plate at the end of the whole process. A stack made of a thousand flakes is shown in Fig.1. Once a stack is numerically built, each element is meshed and becomes the input configuration of a finite element simulation run with OpenRadioss [3]. Both solid and shell elements are investigated to fit the compression behavior of the flakes during consolidation. A first example of compressed flakes is given in Fig.2.
Each step of the process is replicated with lab scale configurations to access the material behavior during the process. A controlled deposition setup has been built to ensure reproducible deposition and fine tune the packing simulation. A tensile test machine is used with temperature-controlled plates to replicate the consolidation step and extract force and displacement evolutions.