水平激励下矩形充液箱体晃动力试验研究

发布时间：2019-07-02 19:24

【摘要】：充液系统在日常生活和工程中随处可见,如液罐车、油轮、燃料箱、渡槽、水库等。与固体不同,充液系统在应用中往往存在着较大的安全隐患:在外界激励作用下,贮箱内液体容易产生持续振荡,改变箱体壁面上的压力分布,从而对约束结构产生不断变化的晃动力和晃动力矩等,对整体系统的稳定性造成极大影响。因此,研究在外界激励下充液系统液体晃动动力学特性有着重要的应用价值。以近年来发展迅速的自走式喷杆喷雾机药箱为背景,本文选取矩形贮箱为研究对象。通过试验手段,对矩形贮箱充液系统在外界激励下的力学特性进行研究。以获取液体晃动所产生的横向晃动力和晃动力矩为目标,设计了横向力试验和垂向力试验两种方案;考虑到药箱和支架的惯性力影响,分别从充液系统整体和液体两个方面进行研究;着重研究影响充液系统力学特性的各种因素,如液体深度、激励频率和激励振幅等。对试验数据进行处理和分析,得出液体深度、激励频率和激励振幅对充液系统晃动力和力矩的影响规律。试验结果表明:(1)充液系统横向力和垂向力表现出近似相同的特性:随着激励频率的不断增大,力逐渐增大;在一阶固有频率附近液体振荡剧烈,测得的力达到极值,呈现出明显的非线性;远离一阶固有频率后,充液系统的横向力和垂向力呈现先急剧下降后攀升的趋势,而液体的晃动力急速下降后趋于平缓。(2)充液系统横向力和垂向力随液体深度和激励振幅的增加而增加,近似为线性变化;液体晃动力随液体深度和激励振幅的增加而增加,但达到一定值后出现饱和。(3)充液系统横向力出现最大值时对应的频率不同:随着液体深度的增加,横向力的极值所对应的频率逐渐减小;但与激励振幅变化没有明显的关系。介绍了液体晃动的等效力学模型,以及由频响函数得到等效力学模型各参数的方法,利用试验数据得出充液系统的频响函数,与二阶等效模型吻合较好。总结了矩形贮箱内液体晃动等效力学模型的一阶晃动质量、晃动质量的位置和等效弹簧刚度随液体深度的变化。
[Abstract]:Liquid filling system can be seen everywhere in daily life and engineering, such as liquid tank car, oil tanker, fuel tank, aqueduct, reservoir and so on. Different from solid, there are often great hidden dangers in the application of liquid filling system: under the action of external excitation, the liquid in the tank is easy to oscillate continuously, which changes the pressure distribution on the wall of the box, thus produces the changing sloshing force and sloshing torque of the constrained structure, and has a great influence on the stability of the whole system. Therefore, it is of great application value to study the dynamic characteristics of liquid sloshing in liquid-filled system under external excitation. Based on the rapidly developing medicine box of self-walking sprayer in recent years, the rectangular tank is selected as the research object in this paper. The mechanical properties of rectangular tank filling system under external excitation are studied by means of experiments. In order to obtain the transverse sloshing force and sloshing torque caused by liquid sloshing, two schemes of transverse force test and vertical force test are designed. Considering the influence of inertia force of charge box and bracket, the whole and liquid aspects of liquid filling system are studied respectively, and various factors affecting the mechanical properties of liquid filling system, such as liquid depth, excitation frequency and excitation amplitude, are studied. The experimental data are processed and analyzed, and the effects of liquid depth, excitation frequency and excitation amplitude on the shaking force and torque of the liquid-filled system are obtained. The experimental results show that: (1) the transverse force and the vertical force of the liquid filling system show approximately the same characteristics: with the increase of the excitation frequency, the force increases gradually, and the liquid oscillates violently near the first natural frequency, and the measured force reaches the extreme value, showing obvious nonlinear; After being far from the first order natural frequency, the transverse force and vertical force of the liquid filling system decrease sharply at first and then climb, while the sloshing force of the liquid tends to smooth. (2) the transverse force and vertical force of the liquid filling system increase with the increase of liquid depth and excitation amplitude, which are approximately linear. The liquid sloshing force increases with the increase of liquid depth and excitation amplitude, but saturates when it reaches a certain value. (3) the frequency corresponding to the maximum transverse force of liquid filling system is different: with the increase of liquid depth, the frequency corresponding to the extreme value of transverse force decreases gradually, but it has no obvious relationship with the change of excitation amplitude. The equivalent mechanical model of liquid sloshing and the method of obtaining the parameters of the equivalent mechanical model from the frequency response function are introduced. the frequency response function of the liquid filling system is obtained by using the test data, which is in good agreement with the second order equivalent model. The first order sloshing mass of the equivalent mechanical model of liquid sloshing in rectangular tank, the position of sloshing mass and the variation of equivalent spring stiffness with liquid depth are summarized.
【学位授予单位】：山东农业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB12

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