Prediction of interlaminar stress in composite sandwich joints
Publicerad
Författare
Typ
Examensarbete för masterexamen
Modellbyggare
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Volymtitel
Utgivare
Sammanfattning
Volvo Bus Corporation is one of the worlds largest bus manufacturers and has a long history
of using traditional construction materials, such as steel and aluminium alloy. In efforts to
meet the demands on reduced emissions andmaintained passenger capacity, the company
has identified curved composite structures as candidates for weight reductions in future vehicles,
where traditional materials today are used. To fully take advantage of the anisotropic
properties of composite materials in these applications, new simulation methods able to
capture the failure behaviour of these structures are needed.
The current study addresses simulation methodologies for capturing the out¡of¡plane loading
and failure behaviour of curved composite structures subjected to bending moments.
Previously developed modelling strategies are discussed and a solid element simulation
methodology is chosen. A benchmarking of available numerical software using a reference
case is performed, where Abaqus is chosen as solver moving forward. Numerical models of
curved composite beam structures are constructed, along with a physical testing protocol
for verification of the numerical models. A set of failure criteria are presented and implemented
in the numericalmodels.
The methodology development shows that the first hand use solver MSC Nastran can not be
used with the available pre and post processors for solid elementmodels where orthotropic
material models are used. Results from the numerical simulations using Abaqus show that
all beam models without a sandwich design, as well as one beam model with a sandwich
design, fail in an out¡of¡plane matrix interface delamination mode. Two further sandwich
beam models predict failure in an in¡plane matrix mode, subject to transverse tensile loading
of 90° plies. The physical testing shows that failure is not initiated in the junction between
the foam core and upper/lower laminate facings, and that the numerical models are
somewhat accurate but too stiff. The results are discussed and future work based on the
developed solid element simulation strategy is suggested.
Beskrivning
Ämne/nyckelord
CFRP, NCF, orthotropic, carbon fiber, curved composites, sandwich structures, LaRC05, Abaqus, MSC Nastran