【作者】 耿彦波；

【导师】 许立忠；

【作者基本信息】 燕山大学 ， 机械设计及理论， 2012， 博士

【摘要】 电磁轨道发射系统是一种先进的动能发射装置。与传统的火炮不同，电磁轨道发射是利用电磁系统中电磁力，它能在短时间内把物体推进到更高的速度，可大大提高发射体的速度和射程，在武器装备、交通运输以及航空、航天等领域具有广阔的应用前景。本文对考虑和不考虑趋肤效应两种情况下电枢所受电磁力进行了研究。分析了主要参数对电枢所受电磁力的影响规律，给出了发射过程中不同阶段电枢的运动方程。依据电磁轨道发射系统的机电模型和电流变化的三个阶段，推导了各阶段能量的计算公式，得出总能量和能量转换效率解析式，分析了系统主要参数对能量和效率的影响规律。结果表明：脉冲电流各阶段时间取特定值时，能量转换效率存在最大值。根据电流在导轨中不同的分布情况，研究了考虑和不考虑趋肤效应时导轨所受的电磁载荷，分析了主要参数对导轨所受电磁力的影响规律。研究了电磁载荷作用下导轨的弯曲应力，并对整个发射过程中导轨应力的变化及其随主要参数的变化规律进行了深入研究。研究发现：考虑和不考虑趋肤效应时导轨所受电磁载荷的差别主要在电枢附近，其它位置差别很小。建立了移动载荷作用下导轨的动力学模型，对弹性基础上两端自由、两端简支和悬臂导轨的自由振动进行了求解。在此基础上，把复杂电磁力载荷划为均布载荷和集中力的组合，分别推导了在匀速和加速载荷作用下导轨的受迫振动公式，研究了电磁轨道发射系统在整个发射过程中载荷到达不同位置和不同速度时导轨的动态响应，讨论了临界速度对导轨动态响应的影响规律，并把均布载荷和集中力作用下的动态响应相加，得到了导轨总的动态响应。研究发现：在导轨间距较大时，必须采用均布载荷和集中力组合的方法求解。考虑导轨的位移对电磁载荷的影响，建立了导轨的机电耦合动力学模型，求解了导轨机电耦合自由振动的固有频率和振动模态，研究了系统参数对固有频率的影响规律，分析了移动电磁力作用下导轨的机电耦合强迫振动，并把计算结果与不考虑耦合的计算结果进行了比较，讨论了系统参数对两种计算结果误差的影响规律。结果表明：在电流较大和弹性基础刚度较小时，必须采用耦合方法求解。利用ANSYS软件对电磁轨道发射系统导轨受力进行了数值模拟，利用APDL方法对两种电磁载荷作用下导轨进行了有限元动力学仿真，并使用ANSYS耦合场分析功能中的顺序耦合方法对通入电流的导轨进行了电磁-结构耦合有限元分析。仿真结果与理论计算结果最大相对误差为9.8%，证明了理论分析的正确性。更多还原

【Abstract】 Electromagnetic rail launch system is an advanced accelerating device. Electro-magnetic rail launch use electromagnetic force of the conductor to accelerate object thatis different from the traditional gun. It can accelerate object to hypersonic velocities in ashort time which can greatly improve the velocity and range of projectile.Electromagnetic rail launch is widely applied in researches of national defence,transportation, aerospace, and so on.In this dissertation, electromagnetic force with and without skin effect is studiedrespectively base on distribution of current in the rails. The change of electromagneticforce along with major parameters is discussed. The motion equation of armature forwhole transformation process is presented. Based on electromechanical model ofelectromagnetic rail launch system, the total process of launching is divided into threestages according to change of current in the rails. The expression of energy in each stageis deduced. The expression of total energy and efficiency is achieved. The change ofenergy and efficiency along with main parameters is analyzed. The result shows that themaximal efficiency occurs when the time of each stage is optimized.According to different distribution of current in the rails, electromagnetic forceacting on rails is investigated when considering and not considering skin effect. Bothelectromagnetic forces are calculated respectively. The change of both electromagneticforces along with main parameters is analyzed. Based on the calculated result ofelectromagnetic force, the equation for calculating bending stress of rail on the elasticfoundation is deduced. The stress distribution in rail in different positions of armature isanalyzed. The change of stress along with main parameters is researched. The resultshows that the maximal difference of the stress for tow methods is near the armature.The dynamics model of rail under the running electromagnetic force is established.The free vibration of rail free at two ends, rail simply supported at two ends andcantilever rail on elastic foundation is solved. The complex electromagnetic load isdivided into uniformed load and concentrated force. The equations for the forced responses of rail on elastic foundation to constant velocity load and accelerate load aredeveloped. The dynamic response of rail to the constant velocity load for differentpositions and the different velocity is studied. The influence of critical velocity isdiscussed. The total dynamic response of rail is achieved by adding the dynamicresponses of rail to uniform load and concentrated force. The result shows that thedynamic responses of rail to concentrated force must be considered when the distance ofrails is greater.Considering the change of electromagnetic load along with displacement of rails, theelectromechanical coupled dynamic equations for the rail are given. Using theseequations, the natural frequencies of the electromagnetic rail launch system and theirchanges along with the system parameters are investigated, the vibration modes of theelectromagnetic rail launch system are discussed, and the forced responses of the rail tothe running electromagnetic force are analyzed. The results of coupled and uncoupledequations are compared and analyzed. The change of difference between the forcedresponses with and without considering electromechanical coupled effects along with thesystem parameters is investigated. The result shows that the coupled method is necessaryfor calculating dynamic response of rail when current is larger and elastic coefficient offoundation is smaller.The electromagnetic force acting on rails is simulated by ANSYS software. Thedynamics response of rail to both running electromagnetic forces is simulated by APDL.The electromagnetism-structure FEM simulation for rails carrying current is implementedin load transfer coupled method of the ANSYS software. The maximal differencebetween simulation and theory is9.8%with emphasis on verification of the theoreticalderivation.更多还原