Title:
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Finite element modelling and characterisation of springback and drawability in aluminium- based alloy :
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The research described in this dissertation characterises the microstructure,
texture and uniaxial tensile mechanical properties of two grades of aluminiumbased
alloy (5000 series (AI-Mg) and 6000 series (AI-Mg-Si)) sheet material.
The sheet material has then been subjected to sheet metal formability testing
for spring back and drawability assessments. The results from the formability
test are compared with simulation results from finite element modelling using
four different material models (isotropic yield criterion, anisotropic yield
criterion, isotropic hardening and linear kinematic hardening). The material
models successfully predict general deformed shapes but failed to simulate
specific features of finished components such as earing heights and sidewall
curls. The formability tests involve stretching, bending and drawing
components. The contribution of each of these components of deformation
makes the final shape of a formed sheet metal component sensitive to the
mechanical properties of the sheet material. It is argued that the material
models used in conjunction with the finite element modelling which rely solely
on mechanical properties calibrated from uniaxial tensile tests, are inadequate
to deal with the effect of complex deformations. It is concluded that more
accurate predictions could be achieved if the material models had included
features of mechanical properties directly influenced by crystallographic
texture and Bauschinger effect. Future material models incorporating these
features need to be calibrated with more advanced mechanical testing
accompanied with a more comprehensive material characterisation
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