材料期刊网

研究了钢质蜂窝夹芯板的室温四点弯曲疲劳行为, 得到疲劳寿命(S-N)曲线. 结果表明, 在载荷比R=0.20时, 钢蜂窝夹芯板疲劳行为体现明显的方向性. L向芯子排列试件较W向易于承受循环载荷, 疲劳强度极限分别为1369和859 N. 基于等效剪切模量退化理论, 建立了寿命预测和损伤演化模型. 结果发现, L向试件损伤开始萌生的循环次数约占总寿命的86%-90%, W向试件高载荷时为73%, 较低载荷时退化为48%. 在不区分芯子排列方向时, 可分别用二阶多项式和指数模型描述高、低载荷水平的损伤演化规律, 模型体现出较强的材料相关性.

The four-point bending fatigue behaviors of steel honeycomb sandwich panels were investigated in this paper. The fatigue tests results were presented in fatigue life (S-N) diagrams. The results show that with a load ratio of R=0.20, the fatigue properties of specimens are significantly influenced by honeycomb cell orientations. The L-direction appears more suitable for cyclic loading than W-direction, and the fatigue strengths reach 1369 and 859 N, respectively. Based on the equivalent shear modulus degradation theory, the life prediction and damage evolution models were developed. Obviously, the lives of damage initiation for L-direction specimens are 86%-90% of the total number of cycles, while 73% at high load and reduce to 48% at low load for W-direction specimens. When the cores orientations were not concerned, the second order polynomial model and exponential model can be adopted to describe the damage evolution trends at high and low load levels, respectively. While the prediction models exhibit strong material dependent.