DFR腐蚀影响系数及其试验测定

Theoretical and experimental determination of DFR-corrosion-influence-factors

为使腐蚀环境下民机结构疲劳分析的细节疲劳额定值(DFR)方法具有更广泛适用性,对DFR腐蚀影响系数与腐蚀环境的关系进行了研究,将DFR的腐蚀影响系数分解为地面停放腐蚀影响系数和空中腐蚀疲劳影响系数,建立了地面停放腐蚀影响系数与地面停放腐蚀时间的关系,以及空中复杂综合环境腐蚀疲劳影响系数与单一介质环境腐蚀影响系数的关系.通过试验测定了各种典型情况的DFR腐蚀影响系数,试验结果说明DFR腐蚀影响系数随着地面停放腐蚀时间的增加和环境腐蚀性的增强而降低,腐蚀疲劳的影响较停放腐蚀的影响更严重.分析实例具体说明了腐蚀条件下DFR方法的具体步骤和所需数据,并体现出疲劳分析中计及腐蚀影响的必要性.

The relationship of detail fatigue rating（DFR）-corrosion-influence-factors and aggressive environments was studied, which makes the DFR method under erosion environments for civil aircraft structures＇ fatigue analysis more applicable to different structure details and different service environments. The way was established to decompose DFR-corrosion-influence-factor into ground-corrosion- influence-factor and air-corrosion-fatigue-influencefactor. The relationship between ground-corrosion-influence-factor and corrosion time as well as the relationship of perplexing environment corrosion-fatigue-influence-factor and mono-medium corrosion-fatigue-influence-factors were studied. Experiments for typical influence factors testing were conducted and reported. The results show that DFR- corrosion-influence-factors are decreasing as the increasing of ground-corrosion-time and the aggravating of environments causticity. The influence of corrosion fatigue is much serious than that of ground-corrosion. The example of structure fatigue analysis with DFR method under corrosive environment shows the detail steps and data requirements. The analysis indicates that DFR of a given structure is reduced significantly by corrosion, and the influence must be taken into account properly in fatigue analysis.