Numerical and experimental study of internal pressure behaviour of integrated and non-integrated weft-knitted reinforced composite elbows

Abstract

This research aims to study the internal pressure behaviour of integrated and non-integrated composite elbows. For this purpose, weft-knitted integrated preforms were produced on the CMC-330-TC Flat knitting machine. Composite elbows reinforced with integrated weft-knitted preform were fabricated using the bladder molding technique. In addition, the non-integrated composite elbows were provided by wrapping the weft-knitted fabric on a plaster mold and hand lay-up impregnation method. To perform the pressure test, a fixture was designed and manufactured. Produced samples were subjected to the internal pressure test. Experimental results show that integrated composite elbow has higher hydrostatic pressure resistant. The internal pressure behaviour of integrated composite was simulated using the multi-scale model. Results showed that integrated composite elbow has a higher resistance against internal pressure than non-integrated composite elbows, so that the integrated elbows failed at 12.5-bar pressure, while the non-integrated elbow failed at 9.5-bar pressure.