Modeling the temperature dependent deformation behavior of fiber reinforced thermoplastics for the analysis of thermoforming processes

Research output: Contribution to conferencesAbstractContributed

Abstract

Numerical optimization of the manufacturing process of lightweight structures made of fiberreinforced plastic (FRP) is of high importance. It can reduce the time to market and can also avoid the production of costly prototypes.
During forming of a plane textile-reinforced polymer into a three-dimensional shape, three basic deformation mechanisms - shear, tension and bending - can be observed. Since the material behavior of the polymer matrix is strongly temperature dependent, a high influence of the temperature on the deformation behavior is observed.
A hybrid modeling approach is used to decouple the almost temperature insensitive tensile and strong temperature dependent bending behavior. The reinforcement part is discretized by membrane elements and will therefore have no contribution to the bending behavior. Fibers are described as an anisotropic non-linear elastic material with orientation vectors stored at the integration points. Their tension/compression and shear behavior are decoupled by the constitutive law and can be defined by means of stress-strain curves and shear response as a function of shear angles of the fibers. In contrast, the matrix is modeled using shell elements and a thermo-elastic-plastic material law.
Experimental data for the parametrization and validation of the modeling approach are the force-displacement curves under tensile loads as well as the shear force vs. shear angle curve. The characteristic behavior for in-plane tension is determined from tensile tests on strip specimens. The typically non-linear shear force vs. shear angle curves are recorded using the picture-frame test. Since the shear force of dry fabrics is mostly influenced by the contact of adjacent fibers, an additional shear resistance due to the polymer matrix can be observed for pre-impregnated composites. Gravimetric cantilever tests may be used to determine the temperature dependent bending. Numerical studies of these tests are performed to investigate the influence of each material parameter for the respectively deformation mode.
The accordingly parameterized material model for the FRP is eventually applied in the simulation of thermoforming processes for the manufacturing lightweight structures. The comparison of the numerical and experimental results of a T-shaped bowl considering the fiber orientation and material feed is used to validate the modeling approach.
Additional parameter studies show the influence of process parameters like forming temperature, friction coefficients, initial fiber orientation and binder force on the deformation behavior of the FRP and its tendency of the occurrence of defects like the formation of wrinkles.

Details

Original languageEnglish
Pages254
Number of pages1
Publication statusPublished - 30 May 2023
Peer-reviewedNo

Symposium

Title93rd Annual Meeting of the International Association of Applied Mathematics and Mechanics
Abbreviated titleGAMM 2023
Conference number93
Duration30 May - 2 June 2023
Website
Degree of recognitionInternational event
LocationTechnische Universität Dresden
CityDresden
CountryGermany

External IDs

ORCID /0000-0002-8416-3311/work/175218302
ORCID /0000-0003-3358-1545/work/175219690
ORCID /0000-0002-2268-6635/work/175220154

Keywords