【摘要】：空間碎片撞擊航天器事件頻發(fā),危害巨大,對(duì)于載人密封艙而言,受撞后果則更加嚴(yán)重�；诼暟l(fā)射的在軌感知系統(tǒng)可以實(shí)時(shí)監(jiān)測(cè)空間碎片撞擊事件,定位撞擊源并進(jìn)行損傷模式識(shí)別。撞擊源的損傷定位是載人密封艙在軌感知系統(tǒng)中的一個(gè)重要功能模塊。航天器在發(fā)射前,需要對(duì)該功能模塊進(jìn)行地面驗(yàn)證,同時(shí)嚴(yán)格保證不能對(duì)載人艙體造成任何機(jī)械損傷(擦傷、成坑等)。本文根據(jù)這種需求,開(kāi)展了關(guān)于空間碎片撞擊信號(hào)的無(wú)損模擬方法用以地面檢測(cè)在軌感知分系統(tǒng)完備性及驗(yàn)證撞擊源定位功能模塊定位精度的研究。超高速撞擊信號(hào)實(shí)質(zhì)是一種板波信號(hào),主要包含有S0、A0、S2三種模態(tài)成分,其中S0模態(tài)板波傳播速度最快。在軌感知系統(tǒng)通過(guò)閾值法獲取信號(hào)S0模態(tài)的到達(dá)時(shí)刻,并通過(guò)虛擬波陣面算法對(duì)撞擊源進(jìn)行定位。本文提出利用壓電直探頭激勵(lì)獲取S0模態(tài)的方法進(jìn)行定位信號(hào)的模擬,并采用數(shù)值仿真和實(shí)驗(yàn)驗(yàn)證相結(jié)合的手段進(jìn)行研究。首先,本文利用ABAQUS仿真軟件建立壓電探頭激勵(lì)聲發(fā)射信號(hào)有限元仿真模型,根據(jù)仿真分析選定經(jīng)Hanning窗調(diào)制的窄帶正弦波信號(hào)作為激勵(lì)信號(hào)的方案,獲取了可靠的用于激勵(lì)源定位的S0模態(tài)。其次,本文利用ABAQUS仿真軟件建立鋁合金加筋板結(jié)構(gòu)二維模型,研究了航天器常用的加筋結(jié)構(gòu)中S0模態(tài)信號(hào)的傳播規(guī)律。根據(jù)仿真分析,針對(duì)單點(diǎn)激勵(lì)下S0模態(tài)信號(hào)幅值較低的問(wèn)題,提出利用陣列激勵(lì)方式加強(qiáng)模擬信號(hào)幅值,提高定位精度的技術(shù)方案。最后,針對(duì)大面積鋁合金平板和加筋板進(jìn)行壓電直探頭無(wú)損激勵(lì)信號(hào)源定位的實(shí)驗(yàn)研究,采用單點(diǎn)激勵(lì)在鋁合金板上垂直激發(fā)Lamb波,模擬空間碎片撞擊聲發(fā)射信號(hào)中的S0模態(tài),測(cè)定了模擬信號(hào)的最遠(yuǎn)傳播距離并在有效監(jiān)測(cè)范圍內(nèi)進(jìn)行模擬撞擊源的定位實(shí)驗(yàn),實(shí)驗(yàn)驗(yàn)證了壓電直探頭激勵(lì)S0模態(tài)信號(hào)模擬撞擊源進(jìn)行定位的方法的有效性。本文提出了一種“等效激勵(lì)環(huán)”的概念,利用“等效激勵(lì)環(huán)”下的陣列激勵(lì)模型進(jìn)行了定位實(shí)驗(yàn),實(shí)驗(yàn)驗(yàn)證了采用“等效激勵(lì)環(huán)”的方式相比單點(diǎn)激勵(lì)能滿足更大的監(jiān)測(cè)面積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.
【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：V528;V416

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本文編號(hào)：2123474