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Shear behavior of thermoformed woven-textile thermoplastic prepregs: An analysis combining bias-extension test and X-ray microtomography
- Source :
- 20TH International ESAFORM Conference on Material Forming (esaform 2017), 20TH International ESAFORM Conference on Material Forming (esaform 2017), Apr 2017, Dublin, Ireland. ⟨10.1063/1.5008011⟩
- Publication Year :
- 2017
- Publisher :
- Author(s), 2017.
-
Abstract
- International audience; Thermoforming allows the manufacture of structural parts for the automotive and aeronautical domains using long fiber thermoplastic prepregs with short cycle times. During this operation, several sheets of molten prepregs are stacked and subjected to large macroscale strains, mainly via in-plane shear, out-of-plane consolidation or dilatation, and bending of the fibrous reinforcement. These deformation modes and the related meso and microstructure evolutions are still poorly understood. However, they can drastically alter the end-use macroscale properties of fabricated parts. To better understand these phenomena, bias extension tests were performed using specimens made of several stacked layers of glass woven fabrics and polyamide matrix. The macroscale shear behavior of these prepregs was investigated at various temperatures. A multiscale analysis of deformed samples was performed using X-ray microtomography images of the deformed specimens acquired at two different spatial resolutions. The low-resolution images were used to analyze the deformation mechanisms and the structural characteristics of prepregs at the macroscale and bundle scales. It was possible to analyze the 3D shapes of deformed samples and, in particular, the spatial variations of their thickness so as to quantify the out-of-plane dilatancy or consolidation phenomena induced by the in-plane shear of prepregs. At a lower scale, the analysis of the high-resolution images showed that these mechanisms were accompanied by the growth of pores and the deformation of fiber bundles. The orientation of the fiber bundles and its through-thickness evolution were measured along the weft and warp directions in the deformed samples, allowing the relevance of geometrical models currently used to analyze bias extension tests to be discussed. Results can be used to enhance the current rheological models for the prediction of thermoforming of thermoplastic prepregs.
- Subjects :
- chemistry.chemical_classification
Thermoplastic
X-ray microtomography
Materials science
Consolidation (soil)
020502 materials
Short cycle
[SPI.MECA.MSMECA]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Materials and structures in mechanics [physics.class-ph]
02 engineering and technology
[SPI.MECA]Engineering Sciences [physics]/Mechanics [physics.med-ph]
021001 nanoscience & nanotechnology
Microstructure
[SPI]Engineering Sciences [physics]
0205 materials engineering
chemistry
Shear (geology)
Polyamide
Composite material
0210 nano-technology
Thermoforming
Subjects
Details
- ISSN :
- 0094243X
- Database :
- OpenAIRE
- Journal :
- AIP Conference Proceedings
- Accession number :
- edsair.doi.dedup.....2d2dec0523c5791917651edc541c34ff