The protection effectiveness of traditional Lightning Strike Protection(LSP)for composite rotor blade of helicopter can be diminished due to the explosion risk in overlapping attachment under lightning strike,so a new...The protection effectiveness of traditional Lightning Strike Protection(LSP)for composite rotor blade of helicopter can be diminished due to the explosion risk in overlapping attachment under lightning strike,so a new protection method based on Air Breakdown and insulating adhesive layer(AB-LSP method)was designed to avoid it.In this study,a numerical method was developed to simulate the electrical breakdown,and verified by experiment results.Based on this method,a Finite Element Model(FEM)was established to investigate the effect of two factors(breakdown strength and initial ablation temperature of adhesive layer)on the LSP effectiveness.The results show that the breakdown strength impacts more to the ablation damage in composite than that of high-temperature resistance.Then,another FEM was established to predict the ablation damage by lightning strike in the AB-LSP method protected composite rotor blade.The mechanisms and potential key parameters(magnitude of lightning current,discharge channel location,adhesive layer thickness,and air gap width)that could affect the protection effectiveness were analyzed.The introduction of air breakdown changes the current conduction path and reduces explosion risk.After rational design,this method can offer effective lightning protection for composite helicopter rotor blade and other composite structures.展开更多
A novel graphene oxide (GO) modified polyurethane thermal conductive insulating adhesive with small addition and excellent insulation properties was prepared by in-situ polymerization using GO as thermal conductive fi...A novel graphene oxide (GO) modified polyurethane thermal conductive insulating adhesive with small addition and excellent insulation properties was prepared by in-situ polymerization using GO as thermal conductive filler.The effects of GO content on the mechanical performance,thermal conductivity,thermal stability and insulation properties of the modified polyurethane adhesive were studied.The results showed that the tensile strength and elongation at break of polyurethane adhesive increased at first and then decreased with the increase of GO content.The thermal conductivity and thermal decomposition temperature of GO/PU composite adhesive can be effectively improved by adding appropriate amount of GO.The tensile strength,thermal conductivity and thermal decomposition temperature of polyurethane adhesive reached the maximum when GO content was 1.5 wt%.The novel GO-modified polyurethane adhesive exhibited good insulation property.The development of GO/PU thermal conductive adhesive will provide a facile method for effectively solving the “trade-off” problem between low filling and high thermal conductivity.展开更多
文摘The protection effectiveness of traditional Lightning Strike Protection(LSP)for composite rotor blade of helicopter can be diminished due to the explosion risk in overlapping attachment under lightning strike,so a new protection method based on Air Breakdown and insulating adhesive layer(AB-LSP method)was designed to avoid it.In this study,a numerical method was developed to simulate the electrical breakdown,and verified by experiment results.Based on this method,a Finite Element Model(FEM)was established to investigate the effect of two factors(breakdown strength and initial ablation temperature of adhesive layer)on the LSP effectiveness.The results show that the breakdown strength impacts more to the ablation damage in composite than that of high-temperature resistance.Then,another FEM was established to predict the ablation damage by lightning strike in the AB-LSP method protected composite rotor blade.The mechanisms and potential key parameters(magnitude of lightning current,discharge channel location,adhesive layer thickness,and air gap width)that could affect the protection effectiveness were analyzed.The introduction of air breakdown changes the current conduction path and reduces explosion risk.After rational design,this method can offer effective lightning protection for composite helicopter rotor blade and other composite structures.
基金Funded by the Liaoning Natural Science Fund Project (No.20180550432)Liaoning Provincial Science and Technology Department Doctoral Research Start-Up Fund Project (No.2020-BS-158)Liaoning Provincial Department of Education Fund Project (Nos.lnfw202014 and LJKQZ2021060)。
文摘A novel graphene oxide (GO) modified polyurethane thermal conductive insulating adhesive with small addition and excellent insulation properties was prepared by in-situ polymerization using GO as thermal conductive filler.The effects of GO content on the mechanical performance,thermal conductivity,thermal stability and insulation properties of the modified polyurethane adhesive were studied.The results showed that the tensile strength and elongation at break of polyurethane adhesive increased at first and then decreased with the increase of GO content.The thermal conductivity and thermal decomposition temperature of GO/PU composite adhesive can be effectively improved by adding appropriate amount of GO.The tensile strength,thermal conductivity and thermal decomposition temperature of polyurethane adhesive reached the maximum when GO content was 1.5 wt%.The novel GO-modified polyurethane adhesive exhibited good insulation property.The development of GO/PU thermal conductive adhesive will provide a facile method for effectively solving the “trade-off” problem between low filling and high thermal conductivity.
