【作者】 刘杨；

【导师】 王诗平；

【作者基本信息】 哈尔滨工程大学 ， 船舶与海洋结构物设计制造， 2024， 硕士

【摘要】 随着各式水中武器的不断发展,舰船生存环境变得尤为恶劣。在现代海战中,舰船遭受中远场水下爆炸冲击载荷的概率要大于近场,中远场冲击载荷一般不会引起结构损伤,但引起的恶劣冲击环境将会对舰载设备产生重大影响,严重时甚至将导致重要设备停止运转,进而削减舰船战斗力甚至生命力。船用推进电机属于船用大型设备,在受到冲击时,大型设备的振动响应、应力分布和变形模式难以进行预测和控制。因此需要研究水下爆炸载荷及陀螺效应作用下电机冲击响应特性,从而摸清其抗冲击薄弱环节,提升电机抗冲击设计水平。本文以此作为出发点,完成的主要内容如下:首先,针对推进电机结构的特点,以某型异步电机作为研究对象建立精细化的有限元模型,采用六面体网格对整机箱体外壳、轴承、转轴等主要部件进行仿真建模,使用时域模拟法对电机冲击响应特性进行研究,分析各部件冲击响应与冲击载荷峰值与冲击载荷脉宽的变化关系。在此基础上,研究转子静止状态下电机整机系统的冲击响应特性及响应传递特性,并进一步探究了转子静止状态下的抗冲击能力。结果表明,各部件的最大应力与冲击峰值成线性关系,间隙的变化与应力的变化趋势基本相同,与载荷峰值呈现线性关系,与载荷脉宽呈现逐渐平缓的增加趋势。结合各部件及间隙失效曲线,形成了电机失效判断准则,为电机抗冲击性能分析提供判断依据。其次,考虑了转动惯量与梁弯曲振动的叠加效应,通过Rayleigh梁-轴模型推导了转轴冲击载荷下的振动方程,得出了转轴转速与转轴横向振动的数值关系,结果表明,转轴的转动会引起载荷施加方向以外的挠度,且当转速增大时该效果越加明显。在此研究结果的基础上对电机转动载荷施加的有效性进行了验证,并对电机转动时冲击响应进行了仿真计算分析,分析了不同转速下电机冲击响应的变化规律。结果表明,转轴转动将放大电机各结构冲击响应,随着转速的增加,冲击响应随之增大。最后,为了提高仿真效率,本文提出了一种转轴冲击响应简化计算模型,探究了简化模型的误差来源。结果表明,简化计算模型计算误差与轴承的冲击环境与弹簧刚度有关。轴承冲击响应作为输入载荷进行转轴响应预报时需以分布质量点或MPC-Tie的方式模拟转轴从而有效避免由于碰撞而产生的环境激增。简化计算模型对于静止或低速旋转时转轴的冲击响应计算较为准确。当转子转速增加时,计算误差会以几何倍数增加,认为在700转以下可应用简化模型方法实现转轴响应的快速计算。更多还原

【Abstract】 With the continuous development of all kinds of underwater weapons and equipment,the living environment of ships has become particularly bad.In modern naval battles,although the probability of ships suffering from middle-far field underwater explosion impact load is greater than that of near-field,the harsh impact environment caused by middle-far field impact load will have a significant impact on shipboard equipment,and even cause important equipment to stop operation in serious cases,thus reducing the ship’s combat and even vitality.Marine propulsion motors belong to large marine equipment.When subjected to impact,the vibration response,stress distribution,and deformation mode of the large equipment are difficult to predict and control.Therefore,it is necessary to study the impact response characteristics of motors under underwater explosion loads and Gyroscopic effect,in order to identify their weak points in impact resistance and improve the level of motor impact resistance design.Taking this as the starting point,the main contents of this paper are as follows:First,according to the structural characteristics of the propulsion motor,a refined finite element model is established with a certain type of asynchronous motor as the research object.The hexahedral mesh is used to simulate the main components of the whole machine,such as the housing shell,bearings and shaft,and the impact response characteristics of the motor are studied by using the time-domain simulation method.The impact response of each component and the relationship between the peak value of the impact load and the pulse width of the impact load are analyzed.On this basis,the impact response characteristics and response transmission characteristics of the whole motor system under the static state of the rotor are studied,and the impact resistance of the rotor under the static state is further explored.The results show that the maximum stress of each component has a linear relationship with the impact peak value,the change of clearance is basically the same as the change trend of stress,the linear relationship with the load peak value,and the load pulse width shows a gradual increasing trend.Based on the failure curves of each component and the gap,the failure judgment criteria of the motor are formed,which can provide the judgment basis for the analysis of the impact resistance of the motor.Secondly,the superposition effect of moment of inertia and beam bending vibration was considered.The vibration equation under shaft impact load was derived using the Rayleigh beam shaft model,and the numerical relationship between shaft speed and shaft lateral vibration was obtained.The results showed that shaft rotation can cause deflection outside the direction of load application,and this effect becomes more pronounced as the speed increases.On the basis of this research result,the effectiveness of applying rotational load to the motor was verified,and the impact response of the motor during rotation was simulated and analyzed.The variation law of the motor impact response at different speeds was analyzed.The results indicate that the rotation of the shaft will amplify the impact response of each structure of the motor,and as the speed increases,the impact response will also increase.Finally,to improve the simulation efficiency,a simplified calculation model of shaft impact response is proposed and the error source of the simplified model is explored.Results show that the calculation error of the simplified model is related to the impact environment of the bearing and the spring stiffness.When bearing impact response is used as input load to predict shaft response,it is necessary to simulate shaft by means of distributed mass points or MPC-Tie to effectively avoid the environmental surge caused by collision.The simplified calculation model is more accurate to calculate the impact response of the rotating shaft at static or low speed.When the rotor speed increases,the calculation error will increase geometrically.It is considered that the simplified model method can be used to quickly calculate the shaft response below 700 rpm.更多还原