A triaxial tensile machine for three-dimensional membrane components: Experimental investigations and numerical simulations

It is found that experimental observations in the first cycle and subsequent cycles are distinctly different for three-dimensional membrane components. The force reduction in the first cycle is caused by plastic deformation during loading-unloading process. The stress state in subsequent cycles is approximately elastic due to the elimination of plastic deformation in the first cycle, indicating that cyclic experiments are suitable for identifying stable mechanical properties. The force differences between X+ and X- directions are related to stiffness difference between warp and weft directions. Moreover, the effects of Z force could result in asymmetrical X and Y forces, especially for small out-of-plane angle. Furthermore, a numerical model is developed for comparing with experimental results. The X and Y forces in terms of loading and unloading are in good agreement with experimental results, which could justify numerical methods.