RESEARCH
EXPERTISE
AND INTERESTS
- layered materials
- functionally graded materials (FGM)
- syntactic structural foams and cellular
structures
- additively printed polymer and metallic materials
- micro-/nano-composites
and hierarchical materials
- interpenetrating phase composites (IPC)
- interpenetrating polymer networks (IPN)
- soft materials
RESEARCH
SUMMARY
Broadly my research deals with (a)
exploration of fracture and failure mechanics of advanced materials using experimental
and computational methods, and (b) development of novel full-field
optical sensors for experimental mechanics and metrology. Early on in my
career I developed full-field optical techniques based on laser speckles and
geometric moiré methods for mapping three-dimensional deformations near cracks
and stress concentrations. Subsequently, I developed a real-time optical method
called Coherent Gradient Sensing (CGS) suitable for dynamic fracture studies
when used in conjunction with ultrahigh-speed photography. CGS since its
invention has found other applications such as metrology of thin
films/structures as well and has become a commercial metrology tool used by the
electronic industry. Concurrently, CGS also contributed to the in-depth
understanding of dynamic fracture mechanics of glass polymers, high strength
steels and dissimilar material interfaces. In my group, an infrared
interferometric sensor has been developed to perform rough surface metrology
and flaw detection. It has also been successfully demonstrated to perform
real-time fracture mechanics investigation on plastically deformed homogeneous
materials and bi-material (e.g., solder-copper) interfaces. My group has been
credited with extending the vision-based method of Digital Image Correlation
(DIC) to study fast-fracture events under rapid loading conditions using
ultrahigh-speed imaging systems. More recently, a new vision-based method
called Digital Gradient Sensing (DGS) has been developed by my group for
failure characterization and NDE of optically transparent and specularly reflective solids.
My current interests include development
and high-strain rate failure characterization of non-traditional materials such
as functionally graded materials, hierarchical micro-/nano-composites,
structural foams, soft materials, layered structures, lightweight structures,
and 3D printed materials. Modeling the failure behavior using computational
methods are integral to many of my research projects. Over the years my
research has received sponsorship of NSF, DOD, and NASA and has resulted in
over 250 research articles in refereed journals and conference proceedings.