准静态及动态载荷加载下聚脲材料的力学性能

Mechanical Properties of Polyurea Material under Quasi-static and Dynamic Loading

为分析聚脲材料在准静态及动态载荷加载下的力学性能变化规律,开展了霍普金森压杆冲击试验研究。利用万能材料试验机和霍普金森杆对聚脲材料进行力学性能测试,获得各应变率下材料应力-应变曲线,结果表明:准静态载荷加载下的聚脲材料切线模量随着应变的增大而呈现类似指数函数增长趋势,动态载荷加载下呈现类似线性降低趋势;随着应变率的增加,聚脲材料强度(拉伸强度和屈服强度)、断裂能逐渐增加。由此可见:聚脲材料具有显著的应变率效应;聚脲材料高应变率载荷加载下的“递减硬化”特性与聚脲抗爆、抗冲击特性密切相关;从低应变率到高应变率加载,聚脲材料存在有橡胶态到玻璃态的转变,强度显著增强。

The changing law of mechanical properties of polyurea material under quasi-static and dynamic loading are studied.The polyurea material was stretched and compressed to obtain the stress-strain curve of the material by using an universal material testing machine and Hopkinson bar,and then the impack test of Hopkinson bar was conducted.The results show that the tangent modulus of polyurea material increases approximately exponentially with the increase in strain rate under quasi-static loading,and decreases approximately linearly under dynamic loading.As the strain rate increases,the strength(tensile strength and yield strength)and fracture energy of polyurea material gradually increase.It is concluded that the polyurea material has a significant strain rate effect,and the“decreasing hardening”characteristics of polyurea material under high strain rate loading are closely related to the anti-knock and impact resistance properties of polyurea.From low strain rate to high strain rate loading,the polyurea material transitions from a rubbery state to a glassy state,and its strength is significantly enhanced.