3.相控陣成像的基本原理 Basics of Phased Array Imaging

只看該作者 · 2015-1-12 21:10:31

常規(guī)超聲儀器和相控陣超聲儀器都使用高頻聲波，核查被測(cè)樣件的內(nèi)部結(jié)構(gòu)或測(cè)量樣件的厚度。它們都以物理學(xué)中支配聲波傳播的相同的基本法則為基礎(chǔ)。這兩種超聲技術(shù)都使用相似的概念表示超聲數(shù)據(jù)。

Both conventional and phased array ultrasonic instruments utilize high-frequency sound waves to check the internal structure of a test piece or measure its thickness. They both rely on the same basic laws of physics that govern sound wave propagation. Similar concepts are employed in both ultrasonic technologies to present ultrasonic data.

而相控陣儀器由于要為帶有16個(gè)晶片到256個(gè)晶片的探頭提供脈沖激勵(lì)的方式（聚焦法則），一般來(lái)說(shuō)都具有多通道性能。與常規(guī)探傷儀不同的是，相控陣系統(tǒng)可以使來(lái)自一個(gè)探頭的聲波以多種不同的折射角度進(jìn)行掃查，或沿線性聲程進(jìn)行掃查，還可以使聲波在一系列不同的深度位置上動(dòng)態(tài)聚焦，從而增強(qiáng)了檢測(cè)設(shè)置的靈活性和性能。

Phased array instruments, on the other hand, are naturally multichanneled as they need to provide excitation patters(focal laws) to probes with 16 to as many as 256 elements. Unlike conventional flaw detectors, phased array systems can sweep a sound beam from one probe through a range of refracted angles, along a linear path, or dynamically focus at a number of different depth, thus increasing both flexibility and capability in inspection setups.

相控陣成像的特性可以使用戶觀察到相對(duì)的點(diǎn)對(duì)點(diǎn)的變化以及多角度的缺陷響應(yīng)，從而有助于缺陷的辨別與定量。這種技術(shù)本身從表面上看似乎極具復(fù)雜性，但它無(wú)需使用常規(guī)UT檢測(cè)方法經(jīng)常需要使用的復(fù)雜的支架與多個(gè)探頭，從而在實(shí)際上不僅簡(jiǎn)化了擴(kuò)大檢測(cè)覆蓋區(qū)域的過(guò)程，而且還提高了檢測(cè)的性能。

Phased array imaging provides the user with the ability to see relative point-to-point changes and multiangular defect responses, which can assist in flaw discrimination and sizing. While this can seem inherently complex,it can actually simplify expanding inspection coverage with increased detection by eliminating the complex fixtures and multiple transducer that are often required with conventional UT inspection methods.