空间碎片撞击信号在整舱定位试验中的无损模拟研究
发布时间：2018-07-15 08:31
【摘要】：空间碎片撞击航天器事件频发,危害巨大,对于载人密封舱而言,受撞后果则更加严重。基于声发射的在轨感知系统可以实时监测空间碎片撞击事件,定位撞击源并进行损伤模式识别。撞击源的损伤定位是载人密封舱在轨感知系统中的一个重要功能模块。航天器在发射前,需要对该功能模块进行地面验证,同时严格保证不能对载人舱体造成任何机械损伤(擦伤、成坑等)。本文根据这种需求,开展了关于空间碎片撞击信号的无损模拟方法用以地面检测在轨感知分系统完备性及验证撞击源定位功能模块定位精度的研究。超高速撞击信号实质是一种板波信号,主要包含有S0、A0、S2三种模态成分,其中S0模态板波传播速度最快。在轨感知系统通过阈值法获取信号S0模态的到达时刻,并通过虚拟波阵面算法对撞击源进行定位。本文提出利用压电直探头激励获取S0模态的方法进行定位信号的模拟,并采用数值仿真和实验验证相结合的手段进行研究。首先,本文利用ABAQUS仿真软件建立压电探头激励声发射信号有限元仿真模型,根据仿真分析选定经Hanning窗调制的窄带正弦波信号作为激励信号的方案,获取了可靠的用于激励源定位的S0模态。其次,本文利用ABAQUS仿真软件建立铝合金加筋板结构二维模型,研究了航天器常用的加筋结构中S0模态信号的传播规律。根据仿真分析,针对单点激励下S0模态信号幅值较低的问题,提出利用阵列激励方式加强模拟信号幅值,提高定位精度的技术方案。最后,针对大面积铝合金平板和加筋板进行压电直探头无损激励信号源定位的实验研究,采用单点激励在铝合金板上垂直激发Lamb波,模拟空间碎片撞击声发射信号中的S0模态,测定了模拟信号的最远传播距离并在有效监测范围内进行模拟撞击源的定位实验,实验验证了压电直探头激励S0模态信号模拟撞击源进行定位的方法的有效性。本文提出了一种“等效激励环”的概念,利用“等效激励环”下的阵列激励模型进行了定位实验,实验验证了采用“等效激励环”的方式相比单点激励能满足更大的监测面积和更高的定位精度的要求。
[Abstract]:Space debris impacts on spacecraft are frequent and harmful, and the impact is more serious for manned capsule. The on-orbit sensing system based on acoustic emission can monitor the impact events of space debris, locate the impact source and identify the damage pattern in real time. The damage location of the impact source is an important function module of the manned sealed cabin in orbit sensing system. Before the spacecraft is launched, it is necessary to verify the function module on the ground and strictly ensure that no mechanical damage (scratches, pits, etc.) can be caused to the manned cabin. According to this requirement, a nondestructive simulation method for space debris impact signals is developed to detect the completeness of the on-orbit sensing subsystem and verify the positioning accuracy of the functional module of the impact source positioning. The hypervelocity impingement signal is essentially a kind of plate wave signal, which mainly contains three kinds of modal components: S0, A0 and S2, among which the S0 mode is the fastest. In orbit sensing system, the arrival time of signal S0 mode is obtained by threshold method, and the impact source is located by virtual wavefront algorithm. In this paper, the method of obtaining S0 mode by piezoelectric direct probe excitation is proposed to simulate the localization signal, and the numerical simulation and experimental verification are used to study it. Firstly, the finite element simulation model of excitation acoustic emission signal of piezoelectric probe is established by Abaqus simulation software. According to the simulation analysis, narrow band sine wave modulated by Hanning window is selected as the scheme of excitation signal. A reliable S 0 mode for excitation source location is obtained. Secondly, using Abaqus simulation software, the two-dimensional model of aluminum alloy stiffened plate structure is established, and the propagation law of S0 mode signal in the commonly used stiffened structure of spacecraft is studied. According to the simulation analysis, aiming at the problem of low amplitude of S0 mode signal under single point excitation, a technical scheme of using array excitation to enhance the amplitude of analog signal and improve the positioning accuracy is put forward. Finally, the experimental study on the localization of nondestructive excitation signal source with piezoelectric straight probe for large area aluminum alloy plate and stiffened plate is carried out. The single point excitation is used to excite Lamb wave vertically on the aluminum alloy plate to simulate the S0 mode in the space debris impact acoustic emission signal. The farthest propagation distance of the simulated signal is measured and the localization experiment of the simulated impact source is carried out within the effective monitoring range. The experiment verifies the validity of the method of simulating the impact source by the S0 mode signal excited by the piezoelectric direct probe. In this paper, a concept of "equivalent excitation ring" is proposed, and the localization experiment is carried out by using the array excitation model under "equivalent excitation ring". The experimental results show that the method of "equivalent excitation loop" can meet the requirements of larger monitoring area and higher positioning accuracy than single point excitation.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：V528;V416
[Abstract]:Space debris impacts on spacecraft are frequent and harmful, and the impact is more serious for manned capsule. The on-orbit sensing system based on acoustic emission can monitor the impact events of space debris, locate the impact source and identify the damage pattern in real time. The damage location of the impact source is an important function module of the manned sealed cabin in orbit sensing system. Before the spacecraft is launched, it is necessary to verify the function module on the ground and strictly ensure that no mechanical damage (scratches, pits, etc.) can be caused to the manned cabin. According to this requirement, a nondestructive simulation method for space debris impact signals is developed to detect the completeness of the on-orbit sensing subsystem and verify the positioning accuracy of the functional module of the impact source positioning. The hypervelocity impingement signal is essentially a kind of plate wave signal, which mainly contains three kinds of modal components: S0, A0 and S2, among which the S0 mode is the fastest. In orbit sensing system, the arrival time of signal S0 mode is obtained by threshold method, and the impact source is located by virtual wavefront algorithm. In this paper, the method of obtaining S0 mode by piezoelectric direct probe excitation is proposed to simulate the localization signal, and the numerical simulation and experimental verification are used to study it. Firstly, the finite element simulation model of excitation acoustic emission signal of piezoelectric probe is established by Abaqus simulation software. According to the simulation analysis, narrow band sine wave modulated by Hanning window is selected as the scheme of excitation signal. A reliable S 0 mode for excitation source location is obtained. Secondly, using Abaqus simulation software, the two-dimensional model of aluminum alloy stiffened plate structure is established, and the propagation law of S0 mode signal in the commonly used stiffened structure of spacecraft is studied. According to the simulation analysis, aiming at the problem of low amplitude of S0 mode signal under single point excitation, a technical scheme of using array excitation to enhance the amplitude of analog signal and improve the positioning accuracy is put forward. Finally, the experimental study on the localization of nondestructive excitation signal source with piezoelectric straight probe for large area aluminum alloy plate and stiffened plate is carried out. The single point excitation is used to excite Lamb wave vertically on the aluminum alloy plate to simulate the S0 mode in the space debris impact acoustic emission signal. The farthest propagation distance of the simulated signal is measured and the localization experiment of the simulated impact source is carried out within the effective monitoring range. The experiment verifies the validity of the method of simulating the impact source by the S0 mode signal excited by the piezoelectric direct probe. In this paper, a concept of "equivalent excitation ring" is proposed, and the localization experiment is carried out by using the array excitation model under "equivalent excitation ring". The experimental results show that the method of "equivalent excitation loop" can meet the requirements of larger monitoring area and higher positioning accuracy than single point excitation.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：V528;V416
【参考文献】
相关期刊论文 前10条
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