SISTEM TOMOGRAFI IMPEDANSI LISTRIK SEBAGAI SARANA UJI TAK RUSAK SEDERHANA
Keywords: impedance, impedansi, non destructive test, tomografi, tomography, uji tak rusak
Abstract
The research was to build the simple electrical impedance tomography system as a nondestructive test equipment. It was carried out experimentally by developing two instrument as main systems. They were phantom and alternating current source. Phantom was built from PVC in 25 cm diameter and 16 electrodes in 6 cm x 2,45 cm rectangle, in which electrodes are placed on the interior boundary of the phantom. The alternating current source was built based on OpAm LM4562. Scanning was conducted by injecting an electrical current through a pair of electrodes and measure the electrical potential between the electrodes by adjacent method collecting data. The output were 256 complete data. The data were reconstructed by Newton Raphson method. Analysis of the results was done visually by comparing between reconstruction image and the reference object. The results showed that the system could generate sufficient reconstruction image, therefore it is promising to be used as a nondestructive test instrument and as instructional tool to understand the basic principles and mechanisms of electrical impedance tomography system.
Telah dilakukan penelitian rancang bangun sistem tomografi impedansi listrik sederhana sebagai sarana uji tak rusak. Penelitian ini dilakukan dengan cara membangun peralatan dan sistem instrumentasi yang diperlukan, yaitu phantom dan instrumen sumber arus bolak balik. Phantom terbuat dari silinder dari PVC yang memiliki diameter 25 cm dan tinggi 6 cm dengan 16 elektroda berbentuk persegi panjang dengan lebar 2,45 cm dan tinggi 6 cm yang terpasang pada permukaan dalam phantom. Sistem instrumen sumber arus listrik bolak-balik dibangun berbasis OpAm LM4562. Proses pemindaian dilakukan dengan cara menginjeksikan arus listrik pada sepasang elektroda dan mengukur potensial listrik antar elektroda dengan metode koleksi data berpasangan, sehingga diperoleh 256 data lengkap. Data hasil pemindaian kemudian direkonstruksi dengan metode Newton Raphson. Analisis hasil dilakukan secara visual dengan cara membandingkan antara citra rekonstruksi terhadap objek uji. Hasil penelitian menunjukkan bahwa sistem tomografi dapat menghasilkan citra rekonstruksi yang cukup baik sehingga menjanjikan untuk digunakan sebagai media uji tak rusak dan digunakan sebagai media pembelajaran dalam rangka memahami prinsip dasar dan mekanisme sistem tomografi impedansi listrik.
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