Accelerated Methods for the Determination of Long Term Fatigue Properties ofGlass Reinforced Plastics for Rotor Craft Applications

摘要

The aim of this work was to develop an accelerated and cost effective method ofgenerating long term fracture data for use in life prediction analysis of structures. Two materials were used in this project. These were S2/8552 and S2/F584, both glass epoxy systems. Delamination onset was monitored at both 5Hz and 20Hz and no difference in cycles to delamination onset was identified. It was concluded that longer term tests could be run at between 15 and 20Hz to represent structural tests at 5Hz. A multistation fatigue machine was modified to allow up to six composite DCB test pieces to be tested at the same time. Each station had its own instrumentation to monitor individual specimens for compliance changes. The machine operated electro-mechanically. The multistation machine was used to generate delamination onset data up to io8 cycles at 17Hz for both materials. For both materials a consistent decrease in the values of G between 10(exp 0) and 10(exp 8) cycles was observed. It was estimated that the increase in frequency and the use of an electromechanical multistation fatigue machine, reduces the cost of generating long term fatigue data to under 5% of that using conventional testing approaches.