Ma Lulu, Liu Feng, Liu Dongyu, Liu Yaolu
Department of Mechanical Engineering, Lamar University, Beaumont, TX 77710, USA.
Nanjing Changjiang Waterway Engineering Bureau, No. 9 Jiangbian Road, Nanjing 210011, China.
Polymers (Basel). 2021 Aug 24;13(17):2839. doi: 10.3390/polym13172839.
The application of fiber-reinforced polymer (FRP) composites is gaining increasing popularity in impact-resistant devices, automotives, biomedical devices and aircraft structures due to their high strength-to-weight ratios and their potential for impact energy absorption. Impact-induced high loading rates can result in significant changes of mechanical properties (e.g., elastic modulus and strength) before strain softening occurs and failure characteristics inside the strain localization zone (e.g., failure mechanisms and fracture energy) for fiber-reinforced polymer composites. In general, these phenomena are called the strain rate effects. The underlying mechanisms of the observed rate-dependent deformation and failure of composites take place among multiple length and time scales. The contributing mechanisms can be roughly classified as: the viscosity of composite constituents (polymer, fiber and interfaces), the rate-dependency of the fracture mechanisms, the inertia effects, the thermomechanical dissipation and the characteristic fracture time. Numerical models, including the viscosity type of constitutive models, rate-dependent cohesive zone models, enriched equation of motion and thermomechanical numerical models, are useful for a better understanding of these contributing factors of strain rate effects of FRP composites.
由于纤维增强聚合物（FRP）复合材料具有高的强度重量比以及吸收冲击能量的潜力，其在抗冲击装置、汽车、生物医学装置和飞机结构中的应用越来越广泛。冲击引起的高加载速率会导致纤维增强聚合物复合材料在应变软化发生之前机械性能（如弹性模量和强度）发生显著变化，以及应变局部化区域内的失效特性（如失效机制和断裂能）发生显著变化。一般来说，这些现象被称为应变率效应。复合材料中观察到的与速率相关的变形和失效的潜在机制发生在多个长度和时间尺度上。其作用机制大致可分为：复合材料组分（聚合物、纤维和界面）的粘性、断裂机制的速率依赖性、惯性效应、热机械耗散以及特征断裂时间。数值模型，包括粘性本构模型、速率依赖性内聚区模型、强化运动方程和热机械数值模型，有助于更好地理解FRP复合材料应变率效应的这些影响因素。
