Research
"We choose to go to the moon in this decade and do the other things, not because they are easy, but because they are hard."
—— John F. Kennedy
"We choose to go to the moon in this decade and do the other things, not because they are easy, but because they are hard."
—— John F. Kennedy
My research interest originated during my undergraduate studies with the performance optimization for a planetary rover suspension system, and since then, I have consistently pursued technology innovation.
Now, my doctoral research primarily focused on dispersion analysis-based structural health monitoring. Specifically, I utilized signal acquisition, digital signal processing, and materials characterization techniques. The goal was to overcome certain limitations of conventional inspection methods, including destructiveness, low efficiency, and inadequate visualization capabilities.
I developed a piezo stack–laser Doppler Vibrometer shear wave sensing system and corresponding time–space wavefield analysis methods to investigate shear waves dispersive behavior in viscoelastic materials. By integrating space–frequency–wavenumber analysis with least-squares dispersion fitting, our approach extracts shear wave dispersion relations and maps local viscoelastic properties (e.g., shear modulus and viscosity).
We did a proof-of-concept experiment on a synthetic gelatin phantom, to confirm that our system can reliably generate shear waves, acquire time-space wavefields, and reveal spatial variations in wave propagating behavior and material parameters. This work could benefit a range of engineering and biomedical applications that rely on accurate viscoelastic characterization.
Accurately characterizing the mechanical properties of additive manufacturing (AM) materials is challenging with conventional methods, which often lack precision or are destructive.
To overcome the challenge, we developed a nondestructive evaluation technique integrating ultrasonic guided wave sensing and advanced frequency-wavenumber analysis enhanced by optimization algorithms. Our method employs programmable ultrasonic excitation and robotic-controlled laser Doppler vibrometry to capture detailed multidimensional acoustic wavefield. This innovative approach effectively determined anisotropic mechanical properties in AM materials, including metals, composites, and ceramics. The results demonstrate the method's reliability and potential for real-time quality monitoring and process optimization in additive manufacturing.
Nuclear power plants rely on ceramic fuel cladding to safely contain radioactive fuel, making it essential to regularly inspect cladding integrity. Traditional inspection methods typically involve destructive testing, damaging the sample, or contact-based methods unable to simultaneously detect defects and evaluate material strength.
To address the problem, we developed a robotic-assisted, non-destructive technique using guided ultrasonic waves. A robotic arm equipped with piezoelectric sensors sends guided waves through silicon carbide ceramic cladding, while a laser measures vibrations without physical contact. Analyzing wave propagation identifies defects (like cracks, notches, and surface pits ) and accurately characterizes mechanical properties such as elastic modulus and stiffness. Our approach can detect defects and measure material properties with accuracy within 5%. We hope this efficient, real-time monitoring system enhances safety in nuclear operations by proactively identifying potential structural failures.
Composites UT Scan
X-Ray CT Scan
Immersed C-scan
Shear Wave Excitation System Miniaturization (Arduino Due Based)
NASA-funded Project: Acoustic Manipulation of Small Objects in Microgravity