Numerical and Experimental Analyses of the Hoop Tensile Strength of Filament-Wound Composite Tubes

The hoop tensile strength of a composite pipe was measured experimentally using the split-disk test method. Then, a finite-element modeling was performed to simulate the split-disk test, and the progressive damage modeling was carried out to predict the maximum load the ring specimen representing the hoop tensile strength can carry. The progressive damage modeling was utilized in the context of continuum damage mechanics, where a failed ply is replaced by a virtual continuum ply with reduced mechanical properties. To degrade the mechanical properties of the failed ply, the linear damage evolution law was used in combination with a linear material softening law. The hoop tensile strength predicted agreed with experimental observations very well, validating the finite-element modeling. The damage progression was monitored during different loading stages, and the sequence of experienced failure modes was investigated. The stress concentration factor at the root of a notch was computed based on the results of finite-element analysis. The stress distribution in the vicinity of the notch was investigated, and a simple manual method was proposed for obtaining the stress in the hoop direction. The stress obtained was compared with results of the numerical simulation, and a good accuracy of the method to determine stresses without employing the finite-element modeling was found to exist.