YOGYAKARTA (KU) - Human life is always interacting with the waves. For that, the phenomenon of waves needs to be learned for the benefit of mankind. One of them is the use of ultrasonic waves to detect defects in solid medium, such as concrete and iron. In this regard, a professor of Information Engineering University of Atma Jaya Yogyakarta, Pranowo ST, MT, managed to create a simulation of discontinuous finite element numerical method for ultrasonic waves modeling.
Because of his research, Pranowo successfully gained his doctoral degree from Electrical Engineering of UGM Graduate School after defending his dissertation in an open doctoral examination at the Auditorium of Faculty of Engineering, Saturday (2/10).
The man born in Magelang who graduated from S-1, S-2, and S-3 programs of the Faculty of Engineering UGM expressed that an important parameter in the wave is the wavelength and frequency. All space dimensions are measured relatively based on the wavelength. Meanwhile, the higher the frequency, the more difficult to learn the phenomena. "Because the object is a complicated form, we proposed the development of element method to higher order discontinuous finite that is able to model the complex shape and able to model the waves with high frequency," said the man who graduated in Mechanical Engineering in 1996.
He said that the application of ultrasonic waves in the industry for quality control has been widely used. An example is the use of ultrasonic waves to evaluate non-destructively the concrete structure and to detect defects in a manufactured product. Seeing these conditions, in-depth research on the ultrasonic waves has also been done many times, especially by means of numerical simulation. This is supported by the rapid development of sophisticated computers.
However, the challenge faced in non-destructive numerical evaluation of ultrasonic modeling (non-destructive testing) is how to develop the numerical method for solving equation of ultrasonic wave model that can cope with complex and heterogeneous domain shape and high accuracy. "Efforts are continuing to develop the numerical method for simulation of ultrasonic wave propagation," he said.
In his research, Pranowo tried using algorithms and extension software of the NUDG framework. The software can be used for simulation of ultrasonic wave propagation in complex medium with isotropic, anisotropic, and heterogeneous materials and wave interaction with cracks. "Discontinuous Galerkin method turned out to be able to be developed further for ultrasonic waves modeling with complex, heterogeneous, and anisotropic forms of media. Phenomenon involving sharp gradients such as wave interaction with cracks can also be captured very well," he said.
He added that the comparison between an exact answer and the method of Spectral Element Method (SEM) and FDTD shows that Discontinous Galerkin method has high accuracy, even slightly higher compared with the SEM and much higher than the FDTD method. Validation with experimental data in the form of transit time in the medium of concrete blocks showed a good fit, the difference is less than 2%. Method of Space-Time Discontinuous Galerkin (STDG) has also been successfully developed for solving elasto-dynamics equations . The use of STDG method makes the numerical calculation accuracy is exponential to the calculation of space and time.
For further research, Pranowo plans to collaborate with UGM geophysical researchers in order to utilize research results to model seismic waves. "This is done considering that Yogyakarta is a vulnerable area to earthquakes and I hope what I'm doing through this research can be useful for the community," said the1272nd doctor of UGM.