电磁发射中导轨应变时空分布的实验研究

Experimental Study on Temporal and Spatial Distribution of Rails Strain in Electromagnetic Launching

掌握电磁发射过程中导轨应变的时空分布特性,是分析导轨失效机理和发展身管延寿技术的前提。文中设计并搭建了基于光纤光栅的导轨应变测量系统,分布式测量了发射过程中导轨的应变量,在此基础上获得了导轨应变时空分布的规律。分析结果表明:在脉冲电流上升段结束时刻附近,导轨应变在电枢位置达到最大值;由于基座紧固在地面的原因,上导轨的应变幅值高于下导轨的应变幅值;在电枢离开装置后,导轨存在欠阻尼振动,获得其固有振动频率约为208Hz,阻尼因子β约为0.0565 ms^(-1)。研究结果可为限制导轨变形、评估身管疲劳寿命以及避免装置共振现象提供有效参考。

It is a prerequisite for analyzing the rail failure mechanism and developing the barrel life extension technology to master the temporal and spatial distribution characteristics of the rail strain in electromagnetic launching.We designed and established a rail strain gauge system based on fiber Bragg grating(FBG),and measured the rail strain variation in the electromagnetic launching in a distributed manner.The law of the rail strain temporal and spatial distribution was obtained from the experimental data.Results show that the rail strain reaches the maximum value at an armature position near the end of the pulse current rising phase.The strain values of the upper rail are higher than those of the lower rail due to the ground fastening.The damped vibration of rail is generated when armature leaves launcher.Multiple measurement results show the launcher natural frequency is about 208 Hz,and the damping factorβis about 0.056 5 ms-1.The conclusions can provide effective references for limiting the rail deformation,evaluating the barrel life,and avoiding the resonance phenomenon.