Pratt & Whitney Canada (P&WC) と Ryerson Universityの協力により作成された、就航中に破壊した航空エンジン高圧コンプレッサーブレードの3次元き裂進展シミュレーションの事例。 FRANC3Dを使用して、初期クラックを挿入、進展にmax tensile stress theoryを使用した解析を実行している。数値手法は、測定された動的ロードと定常応力の重ね合わせでlow cycle fatigue (LCF)とhigh cycle fatigue (HCF)ロード下の応力場を把握するために開発され、予測されたき裂軌道、アスペクト比と形状は、LCFロードのみのシミュレーションと比べて破壊された翼に、より密接に合致した。

資料より抜粋(本Web向けに図番号を変更)：
Under combined HCF+LCF non-proportional cyclic loading, the direction, aspect ratio, and shape predicted by the crack growth simulation shown in Fig. 1 agreed well with the fractured airfoils, indicating that the fractures are due to combined LCF and HCF loading. The concentrated bending force added to simulate the HCF resonant vibration resulted in a direction of crack growth which better aligned with the fractured components. This supports the initial assumption that the single first bending mode was responsible for the crack growth and ultimately led to fracture.



Fig1. Crack growth simulation under combined HCF+LCF loading. Predictions (left) agree well with the fractured airfoils (right) in regard to direction, aspect ratio, and shape.



Fig2. Mode I SIF along crack depth under LCF+HCF Tension and LCF+HCF Compression

参照：Mangardich D., Abrari F., Fawaza Z., Modeling crack growth of an aircraft engine high pressure compressor blade under combined HCF and LCF loading Engineering Fracture Mechanics, Available online 24 April 2019
https://www.sciencedirect.com/science/article/pii/S0013794418312785?via%3Dihub