Experimental assessment of the low cycle fatigue of landing gear components using a strain based analysis approach

点击翻译按钮获取中文摘要

The current fatigue analysis observed by SPPCA Engineering follows a methodology based on repeated stress without accounting for plastic residuals and is considered an adequate estimate of high cycle fatigue life. Generally this method is referred to as "stress life" and will produce acceptable results in low strain high cycle fatigue applications. However, in high strain low cycle applications, the effect of plasticity and mean stresses is not "adequately addressed" for accurate fatigue analysis of landing gear components. Since many landing gear components operate under low cycle fatigue criteria, a methodology that accounts for repeated strain is necessary to accurately predict the fatigue life of these components. The industrial partner, SPPCA, is currently actively pursuing research efforts to develop robust strain based methods for predicting the low cycle fatigue of landing gear components. The scope of this ongoing research effort encompasses the development of a basic fatigue analysis procedure utilizing a strain life approach and benchmarking the procedure against other methods and test data to accurately predict fatigue of landing gear components. In order to fully implement such a methodology, a partnership with Ryerson University is proposed to undertake an experimental study to generate the necessary strain based fatigue data. In particular, such a partnership will enable SPPCA to generate and analyze strain life data focusing on the effect of plasticity and mean stresses and ultimately use such data to develop fatigue analysis models that can be used for design purposes. The testing program will take place in Ryerson's Facility for Research on Aerospace Materials and Engineered Structures (FRAMES).