飞机风挡无机玻璃在不同应变率下的力学行为

摘要

利用电子万能试验机和改进的分离式Hopkinson压杆测试了飞机风挡无机玻璃在2种准静态应变率(4× 10-4、4×10-3 s-1)和2种动态应变率(200、400 s-1)下的单轴压缩力学行为,并利用高速摄像机记录试样破坏过程.实验结果表明:玻璃破坏时表现为典型的脆性材料,随着应变率的提高,材料的压缩强度显著提高.通过观察试样变形过程及变形后的形貌可知,玻璃在压缩载荷下的破坏模式为横向张应力引起的裂纹成核、沿轴向扩展与联结交错导致的失效破坏,并从微裂纹成核扩展和能量耗散的角度对材料的应变率效应做出了合理的解释.%By using an electronic universal testing machine and a modified split Hopkinson pressure bar device,the uniaxial compressive mechanical behaviours of glass used as the windshield of aircraft was tested.The experiments were finished at two quasi-static strain rates(4× 10-4,4× 10-3s-1) and two high strain rates(200,400 s-1).The glass fracture progress was also recorded by a high-speed camera.The experimental results show as follows.Catastrophic brittle failure was observed for the specimens tested at different strain rates.With the increase of strain rate,the compressive strength of the glass increases remarkably.By the fracture images and fragmentation forms,it is known that under compressive loads,the cracks initiate and propagate in the length direction under lateral tensile stress.Then the cracks connect and contact with each other,resulting in fragmentation of the specimen.The strain rate effect is explained properly in the point of microcrack initiation and development as well as energy dissipation.