acoustics3-3

模型大小延伸程序；及实现快速傅里叶变换的小程序。该两程序通俗易懂，适合初学者(Model extension、 FFT)

首先根据高斯白噪声频率充满整个频带的特性，通过双树复小波包变换对高斯白噪声进行分解，利用频带能量泄漏的定量分析方法，验证了双树复小波包变换具有较低的频带能量泄漏特性；其次利用双树复小波包变换逐层分解信号，对每层分解所得分量求其FFT谱的峭度，得到基于双树复小波包变换的谱峭度图，根据图中峭度最大的原则，可以自动准确的选择信号分解最佳层数和最佳分量；最后将基于双树复小波包变换的谱峭度图的故障诊断方法应用于实际工程中，对齿轮故障振动信号进行分析，选择最佳分解层数和分量后利用希尔伯特包络解调，有效准确地提取了故障特征信息，验证了方法的可行性和有效性(The parameters of a filter were determined by experience, and that has a great influence on the results of signal processing. The discrete wavelet packet transform has a larger energy leakage of frequency band, which obviously affected the results of the envelope demodulation. It is necessary to have a method with a lower energy leakage of the frequency band before envelope demodulation. The dual tree complex wavelet packet transform (DT-CWPT) was a new signal processing method that had many good qualities. Because the energy leakage of the frequency band was smaller when the signal was decomposed by a dual tree complex wavelet packet transform, the dual tree complex wavelet packet transform was used to extract the fault feature information in the field of fault diagnosis. In this paper, first, according to the characteristics of Gaussian white noise, whose frequency was full of the whole frequency band, Gaussian white noise was decomposed by a dual-tree complex wavel)

说明：  LM莱文博格马夸特优化算法，python语言(this is a file of LM algorithm which was wroten by python language)

该程序实现的是计算器功能，包含简单的加减乘除，以及取余、求倒等功能计算。(The program is a calculator function, contain simple addition and subtraction, multiplication and division, and modulo, seeking poured functions calculation.)

说明：  uel fortran code for CPE4 with analysis of beam example

对FFT算法的基2时析型实现，在实习时很多专业会用到(Algorithm based on FFT analysis of type 2 o)

用有限差分方法求解波动方程，画出波场快照，模拟波在地下传播！(The wave equation by finite difference method, draw the wave field snapshot, simulate wave propagation in the underground!)

说明：  微分进化算法中的其中两个子程序，还有未上传(Differential evolution algorithm)

FFT with fix point 2*N

fluent软件UDF，用于焊接过程模拟，是高斯分布的面热源。(weld heart source)