本研究探討固體藥柱之低週疲勞性質，以及建立低週疲勞壽限評估方式。除了進行等應變振幅疲勞試驗外，還利用等效之掛載振動頻譜在不同應變水準下進行變動振幅疲勞試驗，以求取疲勞壽限值。在低週疲勞壽限分析中，探討平均應力修正模式及循環計數法之影響，以了解適用於藥柱之低週疲勞壽限評估模式。 本研究求得藥柱之循環應力-應變方程式及應變-壽命方程式。且由研究結果得知當藥柱在掛載頻譜負荷下，以Morrow平均應力修正法搭配雨流區間法進行疲勞壽限分析，可得最佳結果，但若能再加計潛變損傷之影響則更佳。由試件之破斷面觀察發現到，在等應變振幅條件下主要以剝落方式造成損壞，而在變動應變振幅條件則以劈裂方式發生。 This thesis investigates low cycle fatigue properties and fatigue life prediction model of solid propellant. In addition to the constant strain amplitude fatigue test, the spectrum fatigue test of solid propellant was performed. The present fatigue life prediction model is strain based. Effects of strain ratio (R) and cycle counting method on the predicted life were studied. The author obtains the cyclic stress-strain equation and strain-life equation of solid propellant in this study. When the solid propellant under spectrum loading, the best fatigue life prediction model is the strain-life model combined Morrow mean stress correction with rainflow histogram cycle counting method. From the analysis of fractographs, it is seen that many solid grains peel off the matrix on facture surface in R= -1 spectrum fatigue test. While the fracture mechanism changes into split in R = 0.5 spectrum fatigue.
