WO2019071850A1 - 一种频散Lamb波信号分辨率增强方法 - Google Patents

一种频散Lamb波信号分辨率增强方法 Download PDF

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WO2019071850A1
WO2019071850A1 PCT/CN2017/119833 CN2017119833W WO2019071850A1 WO 2019071850 A1 WO2019071850 A1 WO 2019071850A1 CN 2017119833 W CN2017119833 W CN 2017119833W WO 2019071850 A1 WO2019071850 A1 WO 2019071850A1
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distance
lamb wave
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蔡建
袁慎芳
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Nanjing University of Aeronautics and Astronautics
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B06—GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS IN GENERAL
    • B06B—METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, e.g. FOR PERFORMING MECHANICAL WORK IN GENERAL
    • B06B1/00—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency
    • B06B1/02—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy
    • B06B1/06—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction
    • B06B1/0603—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction using a piezoelectric bender, e.g. bimorph
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
    • G01N29/04—Analysing solids
    • G01N29/048—Marking the faulty objects
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
    • G01N29/34—Generating the ultrasonic, sonic or infrasonic waves, e.g. electronic circuits specially adapted therefor
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
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  • the invention relates to a method for enhancing resolution of a dispersion Lamb wave signal, belonging to the field of Lamb wave structure health monitoring.
  • Structural health monitoring technology uses advanced sensors integrated in the structure to acquire information related to structural health status in real time online, combined with advanced information processing methods and structural mechanics modeling methods to extract feature parameters, thereby realizing online health status. Monitoring and evaluation. Structural health monitoring technology is of great significance for improving the safety of engineering structures and reducing maintenance costs. As an ultrasonic guided wave in the thin-plate structure, Lamb wave is far away from the structure and surface damage, so it is widely used in structural health monitoring.
  • Lamb wave damage monitoring In the field of Lamb wave structure health monitoring, high-resolution damage monitoring technology is a hot topic in current research.
  • the resolution of Lamb wave damage monitoring is largely determined by the Lamb wave signal resolution.
  • the Lamb wave signal resolution is often affected by the Lamb wave propagation characteristics including the dispersion characteristics.
  • the Lamb wave dispersion characteristic refers to the phase/group velocity of the propagation which is related to the frequency. This characteristic causes the signal wave packet to expand and deform, which easily causes aliasing of adjacent wave packets, thereby reducing the resolution of the signal.
  • two adjacent wave packets in the Lamb wave signal are too close together, it is easy to cause aliasing of the two, which is mainly limited by the self-resolution of the Lamb wave signal wave packet in the non-dispersion case.
  • the signal resolution enhancement processing method for the dispersion Lamb wave is generally divided into two methods: dispersion compensation and excitation signal optimization.
  • the dispersion compensation method re-compresses the original dispersion-spread signal wave packet, and the excitation signal optimization method
  • the processing method of time reversal and pulse compression reduces the width of the Lamb wave signal packet, and finally achieves the purpose of enhancing the resolution of the Lamb wave signal. From the existing data, the proposed method rarely considers the two aspects of dispersion compensation and Lamb wave signal packet self-resolution optimization to improve the resolution of the dispersion Lamb wave signal and limit the further improvement of signal resolution. .
  • the invention provides a resolution enhancement method for a dispersion Lamb wave signal.
  • the resolution of the Lamb wave signal is further enhanced by adjusting a signal distance delay amplification factor.
  • a method for enhancing resolution of a dispersion Lamb wave signal includes the following steps:
  • the original dispersion curve K 0 ( ⁇ ) of the selected Lamb wave mode is obtained by theoretical calculation or measurement, and the non-distributed wave number curve is calculated.
  • ⁇ and c g0 are the angular frequency and the group velocity of the selected Lamb wave mode at the center frequency, respectively;
  • Frequency domain interpolation processing is performed on the transfer function H( ⁇ ) of the Lamb wave signal propagation, and a Lamb wave distance domain impulse response signal h 1 (r) is obtained, wherein r is a distance variable;
  • step (3) the Lamb wave distance domain impulse response signal obtained by the distance delay amplification is calculated, and the following steps are included:
  • the present invention compensates the Lamb wave signal dispersion to recompress the original dispersion-spreading Lamb wave signal wave packet, and increases the distance wave delay packet to increase the neighboring wave packet in the compensated Lamb wave distance domain signal.
  • the distance interval further improves the spatial resolution of the Lamb wave signal.
  • FIG. 1 is a flow chart of an implementation of a method for enhancing resolution of a dispersion Lamb wave signal provided by an embodiment.
  • Fig. 2 is a schematic view showing the arrangement of piezoelectric sheets in an aluminum plate structure.
  • Figure 3 is a Lamb wave time domain narrowband excitation signal.
  • Figure 4 is a diagram of the original dispersion Lamb wave A 0 mode sensing signal.
  • FIG. 5 is a graph of the calculated Lamb wave A 0 mode original dispersion wave number curve and the non-distributed wave number curve.
  • Figure 6 is a Lamb wave impulse response time domain signal diagram.
  • Fig. 7 is a graph showing a new dispersion wave number of the Lamb wave A 0 mode.
  • Fig. 8 is a sequence diagram of an interpolation map obtained based on a new dispersion wave number curve of the Lamb wave A 0 mode.
  • Figure 9 is a diagram of a Lamb wave distance domain impulse response signal amplified by a delay.
  • Fig. 10 is a sequence diagram of an interpolation map obtained based on a Lamb wave A 0 mode non-distributed wave number curve.
  • Figure 11 is a diagram of a narrowband excitation signal in the Lamb wave distance domain.
  • Figure 12 is a distance domain sensing signal diagram of distance delay amplification.
  • Figure 13 is a high resolution range domain sensing signal map for distance scale recovery.
  • Fig. 14 is a diagram showing the results of dispersion compensation for the original dispersion Lamb wave A 0 mode sensing signal without distance delay amplification.
  • the embodiment adopts a LY21 aluminum plate structure with a size of 1200 mm ⁇ 1000 mm ⁇ 1.5 mm, and the material parameters are shown in Table 1.
  • the narrowband excitation time domain signal v a (t) uses a three-peak sinusoidal modulation signal with a center frequency of 60 kHz, as shown in Figure 3.
  • the original dispersion of the Lamb wave A 0 mode sensing signal v 1 (t) collected by the sensor P B is as shown in FIG. 4, and it can be seen that the dispersion and the signal packet are limited by the resolution of the signal itself, except for the time domain position. Outside the direct-transmission packet with a dispersion spread around 200 ⁇ s, other boundary reflection wave packets are severely aliased and cannot be resolved, which indicates that the signal resolution is low.
  • the original dispersion curve K 0 ( ⁇ ) of the A 0 mode was calculated using the aluminum plate material parameters in Table 1.
  • the group velocity c g0 of the A 0 mode at a center frequency of 60 kHz is 1821.7 m/s
  • the non-distributed wavenumber curve K non ( ⁇ ) is calculated.
  • Figure 5 shows the calculated K 0 ( ⁇ ) and K non ( ⁇ ).
  • the step excitation signal is loaded on the P A as the excitation, and the step response signal is obtained by the sensor P B , and the Lamb wave impulse response time domain signal h(t) is obtained after derivation, as shown in FIG. 6 .
  • the Fourier transform of h(t) is used to obtain the transfer function H( ⁇ ) of the Lamb wave signal propagation.
  • v 2 (r) v 1 (m ⁇ r)
  • v 1 (r) is subjected to distance scale contraction to obtain a high-resolution distance domain sensing signal v 2 (r) with distance scale recovery, as shown in FIG. 13 . .
  • Fig. 14 is a dispersion compensation result v 0 (r) for the original dispersion signal v 1 (t) without the distance delay amplification processing. 4 and FIG. 14, it can be seen that, after dispersion compensation, the wave packets of each dispersion spread in v 1 (t) shown in FIG. 4 are in the non-dispersion distance domain signal v 0 (r) shown in FIG. 13 . Recompression is obtained, and four A 0 mode wave packets of 200-1000 mm distance interval can be clearly distinguished in v 0 (r).
  • the two non-dispersive neighboring wave packets near 1400 mm later are aliased due to their own resolution limitations, around 1800 mm.
  • the two neighboring wave packets are heavily aliased into a wave packet, which indicates that the non-dispersive distance domain signal v 0 (r) after dispersion compensation still needs to further improve its resolution.
  • each wave packet in v 2 (r) is recompressed, and the wave delay of the original severe aliasing in the vicinity of 1400 mm and 1800 mm in v 0 (r) is amplified by the distance delay amplification.
  • Both v 2 (r) can be effectively separated and resolved, as shown by the signals in the two dashed boxes in Figure 13, which illustrates that the Lamb wave signal is optimized by using the method of the present invention on the basis of dispersion compensation.
  • the resolution of the packet further enhances the spatial resolution of the Lamb wave signal, and each wave packet position corresponds to its propagation distance, which improves the convenience of subsequent signal analysis and processing.
  • the basic principle of the invention is: based on transforming the dispersion Lamb wave signal from the time domain to the distance domain to compensate for the dispersion effect of the Lamb wave signal, performing distance delay amplification on the transformed distance domain signal to make the distance domain signal.
  • the distance difference between adjacent non-distributed wave packets increases, which reduces the aliasing of adjacent wave packets and further improves the spatial resolution of the signal.
  • the distance scale of the distance domain signal is restored, so that the distance domain position of the wave packet corresponds to the actual propagation distance, which facilitates subsequent signal processing.

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Abstract

本发明提供了一种频散Lamb波信号分辨率增强方法，属于Lamb波结构健康监测领域。该方法包括下列步骤：(1)获取Lamb波模式的频散波数曲线和非频散波数曲线；(2)求取Lamb波信号传播的传递函数；(3)计算得到距离延迟放大的Lamb波距离域脉冲响应信号；(4)求取Lamb波距离域窄带激励信号；(5)计算得到距离延迟放大的距离域传感信号；(6)求取距离尺度恢复的高分辨率距离域传感信号。本发明在对Lamb波信号频散进行补偿，再压缩原始频散扩展的Lamb波信号波包的基础上，通过距离延迟放大进一步增大了Lamb波信号中近邻波包在距离域中的间隔，提高了Lamb波信号空间分辨率。

Description

一种频散Lamb波信号分辨率增强方法 技术领域
本发明涉及一种频散Lamb波信号分辨率增强方法，属于Lamb波结构健康监测领域。
背景技术
结构健康监测技术利用集成在结构中的先进传感器，在线实时地获取与结构健康状况相关的信息，结合先进的信息处理方法和结构力学建模方法，提取特征参数，从而实现对结构健康状态的在线监测与评估。结构健康监测技术对于提高工程结构安全性、降低维护费用具有重要意义。Lamb波作为薄板类结构中的一种超声导波，其传播距离远并对结构内部和表面损伤均敏感，所以广泛应用于结构健康监测中。
在Lamb波结构健康监测领域，高分辨率损伤监测技术是当前研究的热点。Lamb波损伤监测分辨率很大程度上决定于Lamb波信号分辨率。然而在实际情况下，Lamb波信号分辨率常受到包括频散特性在内的Lamb波传播特性的影响。Lamb波频散特性是指其传播的相/群速度与频率相关，该特性使信号波包发生扩展变形，容易造成相邻波包发生混叠，从而降低了信号的分辨率。另一方面，如果Lamb波信号中两个相邻波包相隔过近，也容易造成两者的混叠，这主要是受限于非频散情况下Lamb波信号波包的自身分辨率。
目前针对频散Lamb波的信号分辨率增强处理方法一般分为频散补偿和激励信号优化这两类方法，其中频散补偿方法通过再压缩原始频散扩展的信号波包，激励信号优化方法则通过时间反转和脉冲压缩等处理方法使Lamb波信号波包宽度减小，最终达到增强Lamb波信号分辨率的目的。从现有资料来看，已提出的方法很少综合考虑频散补偿和Lamb波信号波包自身分辨率优化这两个方面来提高频散Lamb波信号分辨率，限制了信号分辨率的进一步提高。
发明内容
本发明提出了一种频散Lamb波信号分辨率增强方法，该方法在对频散Lamb波信号进行频散补偿的基础上，通过调整信号距离延迟放大因子进一步增强Lamb波信号的分辨率。
本发明为解决其技术问题采用如下技术方案：
一种频散Lamb波信号分辨率增强方法，包括下列步骤：
(1)获取Lamb波模式的频散波数曲线和非频散波数曲线
通过理论计算或测量得到所选Lamb波模式的原始频散曲线K 0(ω)，并计算得到非频散波数曲线
Figure PCTCN2017119833-appb-000001
其中ω和c g0分别为角频率和所选Lamb波模式在中心频率处的群速度；
(2)求取Lamb波信号传播的传递函数
利用结构中激励器和传感器，并通过脉冲或阶跃激励获取Lamb波脉冲响应时域信号h(t)，将Lamb波信号传播的传递函数H(ω)计算为H(ω)＝FT[h(t)]，其中FT[]表示傅里叶变换运算；
(3)计算得到距离延迟放大的Lamb波距离域脉冲响应信号
对所述Lamb波信号传播的传递函数H(ω)进行频域插值处理，得到距离延迟放大的Lamb波距离域脉冲响应信号h 1(r)，其中r为距离变量；
(4)求取Lamb波距离域窄带激励信号
首先确定插值映射序列
Figure PCTCN2017119833-appb-000002
其中
Figure PCTCN2017119833-appb-000003
为K non(ω)的逆函数；
然后计算Lamb波窄带激励频域信号V a(ω)＝FT[v a(t)]，其中v a(t)为Lamb波窄带激励时域信号；
接着将Lamb波距离域窄带激励信号计算为v a(r)＝IFT{V a[Ω non(ω)]}，其中IFT[]表示逆傅里叶变换运算；
(5)计算得到距离延迟放大的距离域传感信号
将距离延迟放大的距离域传感信号v 1(r)计算为v 1(r)＝v a(r)*h 1(r)，其中*表示卷积运算；
(6)求取距离尺度恢复的高分辨率距离域传感信号
对所述距离域传感信号v 1(r)进行距离尺度变换，计算得到距离尺度恢复的高分辨率距离域传感信号v 2(r)＝v 1(m·r)，其中：m为距离延迟放大因子，并且m≥1，r为距离变量。
步骤(3)中计算得到距离延迟放大的Lamb波距离域脉冲响应信号，包括以下步骤：
首先确定新的频散波数曲线K 1(ω)＝K 0(ω)/m，其中m为距离延迟放大因子，并且m≥1；
再将K 1(ω)调整为K 2(ω)＝K 1(ω)-K 1(ω 0)+K non(ω 0)，其中ω 0为中心角频率，K 1(ω 0)为频散波数曲线K 1(ω)在ω 0处的波数值，K non(ω 0)为非频散波数曲线K non(ω)在ω 0处的波数值；
然后计算插值映射序列
Figure PCTCN2017119833-appb-000004
其中
Figure PCTCN2017119833-appb-000005
为所述波数曲线K 2(ω)的逆函数；
接着求取距离延迟放大了的Lamb波距离域脉冲响应信号h 1(r)＝IFT{H[Ω 2(ω)]}。
本发明的有益效果如下：
(1)本发明在对Lamb波信号频散进行补偿以再压缩原始频散扩展的Lamb波信号波包的基础上，通过放大距离延迟因子，增加了补偿后Lamb波距离域信号中近邻波包的距离间隔，进一步提高了Lamb波信号空间分辨率。
(2)本发明最后得到的高分辨率Lamb波距离域信号中波包的距离域位置与其实际传播距离一致，便于后续信号分析和处理。
附图说明
图1是实施例提供的频散Lamb波信号分辨率增强方法的实施流程。
图2是铝板结构中压电片的布置示意图。
图3是Lamb波时域窄带激励信号。
图4是原始频散的Lamb波A 0模式传感信号图。
图5是计算得到的Lamb波A 0模式原始频散波数曲线和非频散波数曲线图。
图6是Lamb波脉冲响应时域信号图。
图7是Lamb波A 0模式新的频散波数曲线图。
图8是根据Lamb波A 0模式新的频散波数曲线得到的插值映射序列图。
图9是距离延迟放大的Lamb波距离域脉冲响应信号图。
图10是根据Lamb波A 0模式非频散波数曲线得到的插值映射序列图。
图11是Lamb波距离域窄带激励信号图。
图12是距离延迟放大的距离域传感信号图。
图13是距离尺度恢复的高分辨率距离域传感信号图。
图14是对原始频散Lamb波A 0模式传感信号进行未经距离延迟放大的频散补偿结果图。
具体实施方式
为使本发明的目的、技术方案和优点更加清楚，以下将参照本发明实施例中的附图，通过实施方式清楚、完整地描述本发明的技术方案，显然，所描述的实施例是本发明一部分实施例，而不是全部的实施例。基于本发明中的实施例，本领域普通技术人员在没有作出创造性劳动前提下所获得的所有其他实施例，都属于本发明保护的范围。
为了便于验证，本实施例采用LY21铝板结构，尺寸为1200mm×1000mm×1.5mm，材料参数见表1。
表1.铝板材料参数
Figure PCTCN2017119833-appb-000006
铝板结构中布置两个压电片P A和P B分别作为激励和传感器，如图2所示。窄带激励时域信号v a(t)选用中心频率为60kHz的三波峰正弦调制信号，如图3 所示。利用传感器P B采集到的原始频散的Lamb波A 0模式传感信号v 1(t)如图4所示，可看到由于频散和信号波包自身分辨率的限制，除了时域位置在200μs附近频散扩展的直达波包外，其它边界反射波包则发生了严重混叠而无法分辨，这说明信号分辨率较低。
本实施例的频散Lamb波信号分辨率增强方法，包括下列步骤：
(1)获取Lamb波模式的频散波数曲线和非频散波数曲线
利用表1中的铝板材料参数计算得到A 0模式的原始频散曲线K 0(ω)。A 0模式在中心频率为60kHz下的群速度c g0为1821.7m/s，由
Figure PCTCN2017119833-appb-000007
计算得到非频散波数曲线K non(ω)。图5给出了计算出的K 0(ω)和K non(ω)。
(2)求取Lamb波信号传播的传递函数
在作为激励的P A上加载阶跃激励信号，利用传感器P B采集得到阶跃响应信号，进行求导后得到Lamb波脉冲响应时域信号h(t)，如图6所示。对h(t)进行傅里叶变换得到Lamb波信号传播的传递函数H(ω)。
(3)计算得到距离延迟放大的Lamb波距离域脉冲响应信号
首先确定距离延迟放大因子m＝2.5，根据公式K 1(ω)＝K 0(ω)/m和K 2(ω)＝K 1(ω)-K 1(ω 0)+K non(ω 0)计算得到K 2(ω)，如图7所示。
然后根据
Figure PCTCN2017119833-appb-000008
计算得到插值映射序列Ω 2(ω)，如图8所示。
再由h 1(r)＝IFT{H[Ω 2(ω)]}计算出距离延迟放大了的Lamb波距离域脉冲响应信号h 1(r)，如图9所示。
(4)求取Lamb波距离域窄带激励信号
由
Figure PCTCN2017119833-appb-000009
确定出插值映射序列Ω non(ω)，如图10所示；
然后对v a(t)进行傅里叶变换得到Lamb波窄带激励频域信号V a(ω)；
根据v a(r)＝IFT{V a[Ω non(ω)]}计算得到Lamb波距离域窄带激励信号v a(r)， 如图11所示。
(5)计算得到距离延迟放大的距离域传感信号
根据v 1(r)＝v a(r)*h 1(r)，计算出距离延迟放大的距离域传感信号v 1(r)，如图12所示。
(6)求取距离尺度恢复的高分辨率距离域传感信号
根据v 2(r)＝v 1(m·r)，对v 1(r)进行距离尺度收缩，得到距离尺度恢复的高分辨率距离域传感信号v 2(r)，如图13所示。
图14则为对原始频散信号v 1(t)进行未经距离延迟放大处理的频散补偿结果v 0(r)。对比图4和图14可知，经过频散补偿，图4所示的v 1(t)中各个频散扩展的波包在图13所示的非频散距离域信号v 0(r)中均得到了再压缩，可在v 0(r)中明显区分出200-1000mm距离区间的四个A 0模式波包。但值得注意的是，如图14中的两个虚线框内的信号所示，在后面1400mm附近的两个非频散近邻波包则由于自身分辨率的限制发生了混叠，在1800mm附近的两个近邻波包则严重混叠为一个波包，这说明频散补偿后的非频散距离域信号v 0(r)仍需要进一步提高自身的分辨率。
对比图13和图14可知，v 2(r)中每个波包得到了再压缩，而且通过距离延迟放大，使v 0(r)中1400mm和1800mm附近原先严重混叠无法分辨的波包在v 2(r)中均能有效分离和分辨出来，如图13中的两个虚线框内的信号所示，这说明利用本发明的方法在频散补偿的基础上，通过优化Lamb波信号波包自身分辨率，进一步增强了Lamb波信号的空间分辨率，而且每个波包位置与其传播距离分别对应，为后续信号分析和处理提高了便利。
本发明的基本原理是：在将频散Lamb波信号从时域变换到距离域以补偿Lamb波信号频散效应的基础上，对变换后的距离域信号进行距离延迟放大，使距离域信号中相邻非频散波包的距离域位置差值增大，从而降低相邻波包的混叠程度，进一步提高信号空间分辨率。最后，再恢复距离域信号的距离尺度，让波包的距离域位置与实际传播距离对应，为后续信号处理提供便利。

Claims (5)

  1. 一种频散Lamb波信号分辨率增强方法，其特征在于，包括下列步骤：
    (1)获取Lamb波模式的频散波数曲线和非频散波数曲线
    通过理论计算或测量得到所选Lamb波模式的原始频散曲线K 0(ω)，并计算得到非频散波数曲线
    Figure PCTCN2017119833-appb-100001
    其中ω和c g0分别为角频率和所选Lamb波模式在中心频率处的群速度；
    (2)求取Lamb波信号传播的传递函数
    利用结构中激励器和传感器，并通过脉冲或阶跃激励获取Lamb波脉冲响应时域信号h(t)，将Lamb波信号传播的传递函数H(ω)计算为H(ω)＝FT[h(t)]，其中FT[ ]表示傅里叶变换运算；
    (3)计算得到距离延迟放大的Lamb波距离域脉冲响应信号
    对所述Lamb波信号传播的传递函数H(ω)进行频域插值处理，得到距离延迟放大的Lamb波距离域脉冲响应信号h 1(r)，其中r为距离变量；
    (4)求取Lamb波距离域窄带激励信号
    首先确定插值映射序列
    Figure PCTCN2017119833-appb-100002
    其中
    Figure PCTCN2017119833-appb-100003
    为K non(ω)的逆函数；
    然后计算Lamb波窄带激励频域信号V a(ω)＝FT[v a(t)]，其中v a(t)为Lamb波窄带激励时域信号；
    接着将Lamb波距离域窄带激励信号计算为v a(r)＝IFT{V a[Ω non(ω)]}，其中IFT[ ]表示逆傅里叶变换运算；
    (5)计算得到距离延迟放大的距离域传感信号
    将距离延迟放大的距离域传感信号v 1(r)计算为v 1(r)＝v a(r)*h 1(r)，其中*表 示卷积运算；
    (6)求取距离尺度恢复的高分辨率距离域传感信号
    对所述距离域传感信号v 1(r)进行距离尺度变换，计算得到距离尺度恢复的高分辨率距离域传感信号v 2(r)＝v 1(m·r)，其中：m为距离延迟放大因子，并且m≥1，r为距离变量。
  2. 根据权利要求1所述的一种频散Lamb波信号分辨率增强方法，其特征在于，步骤(2)中所述结构为铝板结构。
  3. 根据权利要求1所述的一种频散Lamb波信号分辨率增强方法，其特征在于，步骤(2)中所述激励器为压电片P A。
  4. 根据权利要求1所述的一种频散Lamb波信号分辨率增强方法，其特征在于，步骤(2)中所述传感器为压电片P B。
  5. 根据权利要求1所述的一种频散Lamb波信号分辨率增强方法，其特征在于，步骤(3)中所述计算得到距离延迟放大的Lamb波距离域脉冲响应信号，包括以下步骤：
    首先确定新的频散波数曲线K 1(ω)＝K 0(ω)/m，其中m为距离延迟放大因子，并且m≥1；
    再将K 1(ω)调整为K 2(ω)＝K 1(ω)-K 1(ω 0)+K non(ω 0)，其中ω 0为中心角频率，K 1(ω 0)为频散波数曲线K 1(ω)在ω 0处的波数值，K non(ω 0)为非频散波数曲线K non(ω)在ω 0处的波数值；
    然后计算插值映射序列
    Figure PCTCN2017119833-appb-100004
    其中
    Figure PCTCN2017119833-appb-100005
    为所述波数曲线K 2(ω)的逆函数；
    接着求取距离延迟放大了的Lamb波距离域脉冲响应信号h 1(r)＝IFT{H[Ω 2(ω)]}。
PCT/CN2017/119833 2017-10-12 2017-12-29 一种频散Lamb波信号分辨率增强方法 Ceased WO2019071850A1 (zh)

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Publication number Priority date Publication date Assignee Title
CN109145726A (zh) * 2018-07-10 2019-01-04 南京信息工程大学 时频重叠多模式兰姆波信号分离方法
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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20030167141A1 (en) * 2001-12-20 2003-09-04 Staszewski Wieslaw J. Structural health monitoring
US20110058453A1 (en) * 2009-09-08 2011-03-10 Honeywell International Inc. Lamb wave dispersion compensation for eusr approach to ultrasonic beam steering
CN102565201A (zh) * 2011-10-25 2012-07-11 中国人民解放军理工大学 一种基于测量波数曲线的Lamb波频散补偿方法
CN102818860A (zh) * 2012-07-31 2012-12-12 中国人民解放军理工大学 一种具有频偏修正效果的时间－距离域映射方法

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103389339B (zh) * 2013-07-22 2015-08-26 北京工业大学 一种基于时间反转周向Lamb波的大口径厚壁管道缺陷定位方法

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20030167141A1 (en) * 2001-12-20 2003-09-04 Staszewski Wieslaw J. Structural health monitoring
US20110058453A1 (en) * 2009-09-08 2011-03-10 Honeywell International Inc. Lamb wave dispersion compensation for eusr approach to ultrasonic beam steering
CN102565201A (zh) * 2011-10-25 2012-07-11 中国人民解放军理工大学 一种基于测量波数曲线的Lamb波频散补偿方法
CN102818860A (zh) * 2012-07-31 2012-12-12 中国人民解放军理工大学 一种具有频偏修正效果的时间－距离域映射方法

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
CAI, JIAN: "Lamb Research on Dispersion Compensation Methods in Lamb Wave Damage Imaging", CHINA DOCTORAL DISSETATIONNS, 30 September 2012 (2012-09-30) *

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