Investigation On Fatigue Behavior Of Composite Honeycomb Sandwich Structure

Honeybomb sanwich structure has been widely applied in various fields for its advantages, especially in aerospace. In order to guarantee the reliability of the structure, the fatigue problem is often needs careful consideration. With the progress of the technology, the static machanics performance of the honeycomb sandwich structure tends to be stable. The influence of different porous material needs to be considered. In order to investigate the Nomex honeycomb static and fatigue behavior, some research works were carried out as following:This paper first introduces the basic theory of sandwich structure, beam theory and the typical failure mode of the structure were introduced. Three point bending strength are analyzed. The fatigue cumulative damage model of hoeycomb sandwich panel was summarized in this papper.The flat crush of honeybomb sandwich structure and three point bending experimental research works were carried out in this papper. Briefly analyses factors that influence the problems of plane compression, explain the discrete degree of cellular wall strength,and give the distribution of the wall strength. Through the load-deformation curve, analyse the mechanical properties at different stages and compared the three point bending and plane compression failure mode.The flat crush fatigue and three point bending fatigue experimental research works were carried out in this papper. By flat crush and three point bending experiments S-N curves flitting and cumulative damage methods were carried out. Analysis the difference between fatigue failure and static failure.Finally,use the material parameter from chaper 3 and chapter 4 and some data form the manufacturer and relevant paper,established the finite element model. The calculation results and static experiment results are basically the same.The results shows that the reliability of the finite element model. Considering the three point bending failure mode is the same with the core crushing, porposed a method of using compressiong S-N curve to calculate the three point bending life.