In a wide variety of industries, unidirectional fiber reinforced composites are being utilized for high pressure containers and tubes, in which the high axial strength fibers can bear most of the hoop stress. For a thermoplastic unidirectional carbon fiber composite tube, this paper demonstrates how to use numerical simulation to account for such microstructural mechanisms and process-induced variation to more reliably predict the burst pressure and localized stresses within the composite. 

Simulations were performed using the finite element package MultiMech, a fully coupled two-way multiscale finite element solver capable of predicting global structural failure based on microstructural design variables. 

For the thermoplastic composite tube, defects such as resin pockets and non-uniform fiber volume fraction were stochastically inserted into the model to characterize manufacturing variability. Because the defects are inserted randomly, multiple simulations can be run for each scenario to obtain a lower and upper limit of burst pressures for different tubes with different percentages of defects. 

The results demonstrate the ability of the multiscale approach proposed, by following trends observed in experimentation as well as the speed in generating the results for such a nonlinear problem. Furthermore, this paper will demonstrate how multiscale simulation technology can enable composite tube manufacturers to quickly and accurately predict product performance without the need to fabricate and test multiple physical prototypes, thus saving a substantial amount of time and cost. 

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