Influence of the type and number of prepreg layers on the flexural strength and fatigue life of honeycomb sandwich structures

Abstract

This research paper deals with an investigation of the flexural properties measured in a three-point bending test depending on the type and number of the E-glass prepreg layers applied to the facing sides of the resulting sandwich structure used for floor panels in the transport industry. The values of the low-cycle fatigue were measured according to the values of the flexural strength obtained from the static test. Cycling was performed at (70, 60 and 50) % values of the ultimate flexural load. Moreover, a decrease in the flexural strength and stiffness depending on the number of cycles was also studied. For the production of samples, one type of aluminum honeycomb core and various phenolic prepregs with different numbers of layers were used. These samples were produced with two, in practice commonly used methods - compression molding and vacuum bagging. The measured results show that the production technology has a certain influence on the mechanical behavior in bending and the fatigue life of sandwich structures. The experimental results proved that the type of prepreg (defined by the reinforcing fabric and the amount of resin) and the number of layers also affect the properties of these structures. All the obtained results provide useful information for designing the sandwich structures for the transport industry.