Considering anisotropic behaviour and process-induced weaknesses in fibre reinforced polymers in CAE
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Författare
Typ
Examensarbete för masterexamen
Program
Modellbyggare
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Sammanfattning
Computer Aided Engineering (CAE) is widely used for developing new products
nowadays. Through advanced software, it is possible to simulate the reality in the
computer to save time and money when less component testing is needed. Two
examples of CAE are Finite Element Analysis (FEA) and Mould Fill Simulation
(MFS). MFS can be used to simulates the melt flow in the mould of an injection
moulding process and FEA can be used to structurally analyse components when
subjected to various loads. This thesis work was conducted at Thule to investigate
the possibility of consider the anisotropic behaviour and process induced weaknesses
of short fiber reinforced polymers (SFRP) through MFS in Moldex3D with a subsequent
FEA in LS-DYNA. The MFS results was implemented in the FEA through
the usage of material models Mat_157 and Mat_215 which are designed for fibre
reinforced materials. A tensile test using Polyamide 6 reinforced with 30 wt% short
glass fibres (PA6 GF30) specimens was performed and compared with results from
the corresponding MFS and FEA. A subsequent Case Study on Thule’s Outway
Hanging Bike Rack was performed, which also included physical testing, MFS and
FEA. Results indicate that it is possible to capture the anisotropic behaviour of
SFRP by obtaining the fibre orientation through MFS. Also, some process induced
weaknesses, especially weld lines and air traps can be obtained from MFS. In the
FEA, the comparison of material models shows that the implementation of fibre
orientation can increase the reliability of the analysis, but there is a need for material
testing with combined calibration of the material models before they can be
implemented in the daily calculations at Thule.
Beskrivning
Ämne/nyckelord
Polyamide 6, short glass fiber reinforced polymers, anisotropy, weld lines, air traps, structural analysis, FEM, material models, mould fill simulation