Experimental Investigation of an Assembled Hybrid Composite Structure Under Internal Pressure Loading

The purpose of this work is to experimentally investigate the internal pressure behavior of fiberglass E/Vinylester thermoset resin assembled pipes in simple assembled L-shaped tubes made up following the instruction of the NFT57 900 and the DIN 16966 assembly standard. To this purpose, a series of experimental tests based on internal pressure tests (IPT) were realized in an L-shaped tube according to the ASTM D1599 standard. It has been concluded through experimental results that the pressure behavior of E glass/Vinylester tubes can be described by three phases: elastic behavior, nonlinear behavior resulting from leakage propagation, and tube failure. The damage evolution was identified through two methods (1) with a macroscopic observation which was carried out to identify the macroscopic leakage and (2) microscopic observations which were conducted revealing the matrix and the fiber failure. The main novelty of this paper is divided into two points (a) extending the common studies realized on simple or assembled water-filled GFRP pipes specimens to cover water-filled GFRP L-shaped pipes structure subjected to an internal compression test, and (b) the mechanical investigation of DIN/NFT butt to butt welded joined structure over internal compression test until failure.