Influence of fiber tension during filament winding on the mechanical properties of composite pressure vessels

During the manufacturing of composite pressure vessels, the fiber tension of the filament winding process has an important influence on the mechanical properties as well as on the gravimetric efficiency of the structure and is therefore investigated within this paper. Three series of samples were manufactured and tested: A) steel liners as reference, B) composite vessels with low fiber tension of 3 N, and C) vessels with high fiber tension of 80 N. The manufacturing process is discussed in this paper with special focus on the parameter of fiber tension and its related challenges. Burst tests with strain measurements and acoustic emission (AE) were conducted, and a statistical analysis of the results is presented. Additional numerical investigations on the structural behavior of the vessels and effect on the gravimetric efficiency are performed to support the experimental result. The investigations show that the increase in fiber tension induced compressive stress on the steel liner, leading to an increase in burst pressure and influence on AE. Furthermore, the fiber volume fraction (FVF) of the composite laminate increased due to increased fiber tension, resulting in higher mechanical properties and an improvement in gravimetric efficiency.