The purpose of this article is to investigate the effect of an initial pre-damage induced by a fatigue loading on the tensile dynamic behavior of Advanced Sheet Molding Compounds (A-SMC). Tension-tension fatigue preloading at a frequency of 30 Hz is performed at various applied stress levels prior to subject the A-SMC specimens to tensile tests at different strain rates, namely: 10⁻³ s⁻¹ (quasi-static), 1 s⁻¹ and 60 s⁻¹. The developed experimental approach provided significant findings in terms of residual behavior and damage accumulation in relation to the applied pre-fatigue loading conditions. Indeed, it has been shown that the overall quasi-static and the dynamic responses are strongly affected by the level of fatigue number of cycles reached prior to applying the high strain loading. The effect of fatigue pre-damage is found also strongly strain-rate dependent. Experimental results showed that the damage threshold in terms of stress and strain increased with strain rate. However, for a given strain-rate the damage stress threshold depends on the number of cycles applied during the fatigue preloading.

本文的目的是研究由疲劳载荷引起的初始预损伤对高级薄板模塑料（A-SMC）的拉伸动力学行为的影响。在对A-SMC样本进行不同应变速率（即10 ^-3  s ^-1（准静态），1 s）的拉力试验之前，在各种施加的应力水平下，以30 Hz的频率进行拉应力疲劳预加载。^-1和60 s ^-1。相对于所施加的疲劳前载荷条件，已开发的实验方法在残余行为和损伤累积方面提供了重要的发现。实际上，已经表明，在施加高应变载荷之前，总的准静态响应和动态响应受疲劳程度的循环次数的强烈影响。还发现疲劳预损坏的影响也与应变率密切相关。实验结果表明，在应力和应变方面的损伤阈值随应变速率的增加而增加。但是，对于给定的应变率，损伤应力阈值取决于疲劳预加载期间施加的循环次数。