Extending the effective temperature model to the large strain hardening behavior of glassy polymers
Extending the effective temperature model to the large strain hardening behavior of glassy polymers
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DOI：
10.1016/j.jmps.2020.104175
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发表时间：
2021
影响因子：
5.3
通讯作者：
Zheliang Wang;Jingkai Guo;J. Seppala;T. Nguyen
中科院分区：
文献类型：
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作者：
Zheliang Wang;Jingkai Guo;J. Seppala;T. Nguyen
无定形聚合物在大应变下表现出粘塑性应变硬化行为。为了描述这种硬化行为，我们已经开发了一个有效的温度模型的非平衡行为的无定形聚合物，将网络取向和松弛在大的塑性变形的影响。网络方向的发展被引入作为一个背应力，产生运动硬化的应力响应，而网络松弛描述的硬化响应的温度和应变速率的影响。将该模型应用于聚碳酸酯（PC）的热机械行为模拟，通过标准动态频率扫描和差示扫描量热法测试确定模型参数。模拟结果表明，该模型可以定量捕捉硬化模量的应变，应变速率和温度的依赖关系，以及卸载和再加载行为在单轴压缩试验中测量。我们应用该模型来研究塑性耗散对聚合物长丝从刚性基底剥离的影响，以指导剥离测试的设计，从而测量通过熔融挤出增材制造工艺制造的聚合物的固有断裂韧性。
Amorphous polymers exhibit a viscoplastic strain hardening behavior at large strains. To describe this hardening behavior, we have developed an effective temperature model for the nonequilibrium behavior of amorphous polymers that incorporate the effects of network orientation and relaxation at large plastic deformation. The development of network orientation is introduced as a backstress that produces kinematic hardening in the stress response, while network relaxation describes the effects of temperature and strain rate on the hardening response. The model was applied to simulate the thermomechanical behavior of polycarbonate (PC) to determine the model parameters from standard dynamic frequency sweep and differential scanning calorimetry tests. The simulation results showed that the model can quantitatively capture the dependence of the hardening modulus on strain, strain rate, and temperature, as well as the unloading and reloading behavior measured in uniaxial compression tests. We applied the model to investigate the effect of plastic dissipation on the peeling of a polymer filament from a rigid substrate to guide the design of peel tests to measure the intrinsic fracture toughness of polymers fabricated by melt extrusion additive manufacturing processes.