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超聲波頻譜分析：探索焊接背後的“聲音密碼”

在超聲波焊接 這一精密制造領域，頻譜分析是一項至關重要的技術。它如同焊接過程中的“聲音密碼” ，通过解析超聲波信号的频率特性，为我们揭示了焊接过程中的种种奥秘。今天，就让我们一起走进超聲波频谱分析的世界，探索它如何为超聲波焊接技术赋能。

航拍外景

連續聲波與脈沖聲波

超聲波頻譜分析的對象是超聲檢測中使用的脈沖聲波（以下簡稱脈沖波），因此首先應了解有關脈沖波的基礎知識。本章1.1節給出了超聲波的定義，介紹了機械波與電磁波的頻率及譜區； 1.2 節定義了描述超聲波的基本物理量，如聲速、頻率、波長等。

1.1超聲波

波动是物质的一种运动形式，振动是波动产生的根源。波动有机械波和电磁波之分。机械波是由于机械振动在弹性介质中引起的波动过程，例如水波、声波、超聲波等;電磁波是由于電磁振蕩所産生的變化電場和變化磁場在空間的傳播過程，例如無線電波、紅外線、可見光、紫外線、倫琴射線等。

超聲波属于机械波，是机械振动在弹性介质中的传播。从频率角度并以人的可感觉频率为分界线，可将声波划分为次声波、可闻声波、超聲波、特超聲波及晶格振动。图1-1号为机械波与电磁波波谱的频段划分及名称，其中，超聲波是指频率高于 20kHz的聲波。

图1-1机械波和电磁波波谱比较

彈性介質是指相互間由彈性力連系著的質點所組成的物質，可以用圖1-2所示的簡化模型來表示，將其看做由許多質量微小的質點集合而成的點陣。質點之間是靠彈性力相互連接的。因此，當彈性介質中的質點在外力作用下産生振動時，該振動就會靠彈性作用傳遞給相鄰的下一質點 :並且一個接一個地傳播下去。由此，振動由振源不斷向遠處傳播，形成機械波。

物质的弹性模型

關注灵科超聲波 ，我們將會在下個章節中對節對連續聲波 ( 以下簡稱連續波) 和脈沖波進行了區分，重點指出脈沖波包含一系列不同頻率成分的正弦 ( 或余弦)波；以及進一步介紹了寬脈沖和窄脈沖，以及脈沖寬度和頻帶寬度等基本概念。

超聲波頻譜分析：探索焊接背後的“聲音密碼”（二）

灵科超聲波焊接：以科技之力，筑牢母婴用品安全防线

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