Pre-Study of Determination of Elastic Modulus By Ultrasonic Testing

• Main Author: Wibisono (NIM : 13713019), Gatot
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/22240
• Institution: Institut Teknologi Bandung

Elastic modulus is important material property especially on structural application. Generally, elastic modulus depends on constituent elements, crystal structure, and void fraction. Elastic modulus of metals are constant relatively although they have different treatment. Meanwhile, elastic modulus of ceramics could vary because it depends on porosity fraction. General method for determining this property is mechanical testing. This testing requires extensometer, strain gauge, or dial gauge to measure deformation. This testing also require preparation of specimen. Principally, ultrasonic testing could be conducted to determine elastic modulus because wave propagation depends on elastic property and density of material. The aim of this research is to determine elastic modulus of some metals dan ceramics using ultrasonic testing pulse-echo technique. The experiment parameter was frequency of probe i.e 1, 2, and 4 MHz. The validation of ultrasonic testing was conducted by two methods. Method A require two different wave distance of flight. Method B require a material as reference which its thickness and wave velocity are known. The results for metals was compared with elastic modulus from literature. Both methods showed good results with maximum error 6,5% as long as using true poisson ratio of metal. Method A could be used to determine Poisson ratio and elastic modulus with better result than method B. Results of method A on ceramic were compared with results from bending test. Result for glass which non-porous material showed good result with error lower than 5%. Results for other porous-ceramics were still contained error up to 1443% due to effect of attenuation. Testing on red tile showed that 1 MHz probe could improve accuration in determining elastic modulus of ceramics. However, testing on other porous-ceramics showed different trend. It was due to near-field effect.