【作者】 陈磊；

【导师】 肖伟科；

【作者基本信息】 哈尔滨工业大学 ， 机械（专业学位）， 2022， 硕士

【摘要】 对星体进行侵彻式探测,勘查弹内部的科学载荷以及连接机构可能会因为侵彻过程而承受较高冲击过载,这种高过载环境可能导致科学载荷受损、失效,以及端盖螺栓连接结构的松动、失效,严重威胁到勘查弹整体结构的安全。通过理论分析、数值仿真相结合的方法,对侵彻过程中勘查弹各部位的响应状态进行了分析,验证了替代靶体作用的压力载荷数值模拟方法的可行性,并对勘查弹侵彻模拟星壤工况下的减振防护以及端盖螺栓连接机构的松动特性进行研究。基于弹靶侵彻仿真对勘查弹不同部位以及内部不同科学载荷的冲击过载特性进行研究。针对勘查弹可能面临的星壤工况,选取可描述模拟星壤力学行为的材料模型及参数,开展了不同速度工况下垂直侵彻仿真,获取勘查弹不同部位以及内部不同科学载荷的过载响应信息。基于结构固有频率和过载分布规律,对勘查弹整体的过载分布特性进行系统分析。为勘查弹减振防护研究提供了一定的数据支持。采用替代靶体作用过程的压力载荷方法,开展了侵彻模拟硬质星壤数值仿真,验证了该方法的可行性。为了提高勘查弹过载仿真的计算效率,将勘查弹的刚体过载信号转换为勘查弹头部表面的压力载荷信号,还原了侵彻仿真中弹体的受力过程。该仿真方法不仅模拟了勘查弹的运动过程,还实现了对勘查弹侵彻过程中内部载荷过载响应过程的仿真,增强了其工程适用性。基于压力载荷数值模拟方法对勘查弹内单层小尺寸垫片的减振防护效果开展研究。从科学载荷的过载特性变化、应力变化以及载荷舱相对位移变化方面,对金属垫片、聚四氟乙烯垫片、硬质聚氨酯垫片的缓冲特点和减振效果进行对比分析。为勘查弹内单层小尺寸垫片选择合适的缓冲材料提供了一定的依据。基于螺纹区域法对端盖螺栓连接受冲击松动行为进行研究。对螺纹松动原理进行了分析,利用螺纹区域法开展数值仿真。在螺栓轴力变化、危险区域螺纹应力变化以及螺纹接触状态变化方面,研究了冲击过载和初始预紧力对螺栓松动的影响,为勘查弹端盖螺栓连接提供了一定的防松建议。更多还原

【Abstract】 For penetrating detection of celestial bodies,the scientific payload inside the penetrator and the connection structure may be subjected to high overload due to t he penetration process.This high overload environment may damage the scientific payload,loosen the bolted connection structure of the end cap loose,and threaten the safety of the overall structure of the penetrator.Through the combination of theoretical analysis and numerical simulation,the response state of each part of the penetrator is analyzed,and the feasibility of the numerical simulation method of pressure load to replace the action of the target is verified.Under the simulated planet-soil condition,the vibration reduction of the scientific payload and the loosening characteristics of the end cap bolted connection structure are studied.Based on the target penetration simulation,the impact overload characteristics of each part of the penetration and different internal scientific loads are studied.Under the possible planet-soil condition,the material model and parameters that can describe the mechanical behavior of the simulated planet-soil are selected.To obtain the overload response state of different parts of the penetrator and different internal payloads,the vertical penetration simulation under different speed conditions of the penetrator is carried out.Based on the natural vibration frequency and acceleration distribution characteristics of the structure,the overall overload distribution characteristics of the penetrator are systematically analyzed.Some data are provided for the study of vibration reduction of the penetrator.By using the pressure load method to replace the action process of the target,under the simulated hard planet soil,the penetration simulation was carried out,and the feasibility of the method was verified.In order to improve the computational efficiency of the penetrator overload simulation,the rigid body ac celeration of the penetrator was converted into the pressure load on the surface of the head of the exploration projectile,and the force process of the penetrator in the penetration simulation was restored.The simulation method not only simulates the mov ement process of the penetrator,but also realizes the simulation of the overload response process of the internal scientific payload during the penetration process of the penetrator,which enhances its engineering applicability.Based on the pressure load method,the vibration reduction effect of the single-layer small-sized gasket in the penetrator is studied.From the changes of overload characteristics of scientific payload,stress and relative displacement of payload compartment,the buffer characteristics and vibration reduction effects of metal gaskets,PTFE gaskets and PU gaskets are compared and analyzed.It provides a certain basis for selecting the appropriate buffer material for the single-layer smallsized gasket in the penetrator.Based on the pressure load simulation method,the vibration reduction effect of the single-layer small-sized gasket in the penetrator is studied.From the changes of overload characteristics of scientific payload,stress and relative displacement of payload compartment,the buffer characteristics and vibration reduction effects of metal gaskets,PTFE gaskets and rigid polyurethane gaskets are compared and analyzed.It provides a certain basis for selecting the appropriate buffer material for the single-layer small-sized gasket in the penetrator.Based on the simplified thread modeling method,the impact loosening behavior of the end cap bolted connection structure was studied.The principle of thread loosening is analyzed,and the numerical simulation is carried out by u sing the simplified thread modeling method.In terms of the change of bolt axial force,thread stress in dangerous area,thread contact state,and the influence of shock overload and preload on bolt loosening is studied,and some suggestions for preventin g loosening of end cap bolted connection structure are provided.更多还原