engleski

Inter-layer bonding characterisation between materials with different degrees of stiffness processed by fused filament fabrication

One of the main benefits of material extrusion additive manufacturing, also known as fused filament fabrication (FFF) or 3D printing, is the flexibility in terms of printing materials. Locally reinforced components can be easily produced by selectively combining reinforced with unfilled tough thermoplastics. However, such multi-material composites usually lack sufficient weld strength in order to be able to withstand operation loads. The present study attempts to close this gap by characterising the cohesion between the strands of two materials with different stiffness, namely neat PLA and short carbon fibre reinforced PLA (CF- PLA), produced by FFF using advanced fracture mechanical techniques. The full set of engineering constants of both materials were obtained under the assumption of transverse isotropy from tensile tests in combination with digital image correlation. Double cantilever beam (DCB) and cracked round bar (CRB) tests were used to determine the critical energy release rate (GIc ). Both tests were in good correlation with each other and revealed that the interlayer PLA/CFPLA bonding was at least as tough as the interlayer CF- PLA/CF-PLA bonding.

Fused filament fabrication ; Fracture mechanics ; Double cantilever beam test ; Cracked round beam test ; Digital image correlation

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