Analysis of blast vibration characteristics by using discretization of continuous wavelet transform
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摘要: 应用连续小波变换的离散化关系,针对一个改进的L-P(littlewood-paley)小波基函数,给出了一种实现频率完全分割的时频特征分析方法,并对爆炸振动时频特征进行了研究。80 kg TNT地面爆炸时地面垂向振动速度的时间能量密度分布情况表明,在质点振动峰值速度到达时刻爆炸振动的频率范围比较宽,而其他时刻的振动频率相对较为集中,时频能量分布的峰值正好对应于爆炸振动速度的峰值到达时间。基于小波变换的爆炸振动频谱特征与Fourier变换的结果具有良好的一致性。此外,还给出了利用小波变换结果建立爆炸振动随机演变理论模型的基本方法。Abstract: A non-overlapping frequency approach to analyze the time-frequency characteristics of vibration signals is presented by means of the discretized version of continuous wavelet transform based on a modified L-P (littlewood-paley) wavelet basis function, and it is used to study the time-frequency characteristics of blast vibrations in this work. Energy density distributions of vertical ground velocities for 80 kg TNT explosion on the ground surface varying with time show that at the moment of peak particle velocity arriving, the frequency range of blast vibrations is very wide, being the relatively narrow bands at the other moments, and the peak time-frequency energy just corresponds to the peak particle velocity arriving time of blast vibration. The power spectra of blast vibrations through wavelet transform method are agreement with those from Fourier transform. Additionally, the principle of modeling blast vibrations as random evolutionary processes by using the wavelet transform results is outlined.
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Key words:
- mechanics of explosion /
- time-frequency /
- wavelet transform /
- blast vibration /
- random vibration
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