Summary of Research Work and Graduate Students
High Strain Rate Properties of Composite Materials
Today,
materials are being selected and used without the necessary property data to
accurately predict their behavior under impact at extreme temperatures. For
applications involving high strain rates and extreme temperatures, fundamental
test data and experimental models to predict material properties are needed.
Our research addresses this deficit and provides predictive capability to
ensure that designs are optimized for structural integrity and weight
efficiency including when the structure is subjected to dynamic loading at
extreme temperatures. A Split-Hopkinson Pressure Bar Apparatus is built to
conduct
the high strain rate tests.
Nanofoam Composites
Both
nanofoam and sandwich composites will be investigated in order to understand
their basic fundamental properties. Major advantages are expected to result
from the development of the nanofoam composite. These are: 1) a dramatic
increase in the surface area of the interface between the reinforcing elements
(microballoons) and the matrix; 2) a remarkable decrease in density due to the
spacing between nanofibers; 3) use of the carbon nanofibers for electrical and
thermal conductivity applications; and 4) elimination of nanofibers’
agglomeration in the matrix or the need for nanofibers’ surface
modification to achieve good dispersion.
Self-Healing Fiber Reinforced Composites
The plan is to develop and characterize
self-healing fiber-reinforced polymer matrix composites. The idea is inspired
by natural living systems that initiate an autonomic healing process in
response to damage. A combination of hollow fibers, solid fibers, hollow
microspheres, resin, and a healing agent composed of a monomer and a catalyst,
is carefully assembled to develop self-healing fiber-reinforced polymer matrix
composites.
ENHANCED NDE DEVELOPMENT: Adhesive Bond Integrity Assessment
The
goal of this project is to further develop current nondestructive evaluation
(NDE) methodology for characterization of the adhesive layer between composites
and other materials such as metals. At the present, the use of composite
materials in the petrochemical, oil and gas supply industries is not widespread
mainly because of the lack of knowledge and confidence in these materials for
use in transportation and storage of these chemical products. Composite
materials can increase the safety of storage and transportation means for
chemical supplies, because of their ability to deform more than metals without
fracture, and therefore increase the safety of the public and the environment.
However, their use is limited due to the lack of sufficient bonding mechanism
of advanced composites with other metals and lack of acceptable means of
assessing the bond integrity. Adhesive bonding is now just started being
accepted by some industries. However, robust and reliable bond evaluation
method is lacking. In this aspect, both the short and long term benefits of the
proposed non-destructive investigation will ensure the integrity of composite
materials and the bonding of these materials during mechanical, environmental,
and static testing. Several tasks, ranging from specimen fabrication to
advancement of existing methods, will be performed in close collaboration with
Bell Helicopter to achieve the proposal objectives.
Composite
Sandwich
structure materials are widely used in structural application. Their
importance in weight sensitive applications is evident by their extensive use
in aerospace sector. Construction of sandwiches in two distinct parts,
namely, core and skins, provides greater design flexibility. Suitable
combination of core and skin materials can be found to meet the predetermined
performance requirements. The popular choices of core materials include
honeycomb structures and rigid and flexible foams having open pore or close pole
structure. The aim of the investigation undertaken is to develop a better
understanding of hollow particle filled polymeric materials for their potential
use as core in sandwich materials. This will be useful in reducing the design
tolerances leading to weight saving and better estimation on safety aspects of
the material under the given conditions.
Mechanics & Design of Composite Materials
Excellent
mechanical properties such as high-strength, low-weight, fatigue life, and
impact resistance, as well as advanced manufacturing methods and tailor ability
of the lay-up make polymer matrix composites attractive candidates for use in
several performance-oriented structures. One use of composite materials is
in the oil industry, where composite sucker rods have just started replacing
steel rods in rod pumping which is the most common lift technology used in
domestic oil production. These composite sucker rods consist of composite rods
and steel endfittings. However, these composite sucker rods are
experiencing fatigue failure. Our research focuses on resolving the fatigue
failure from two directions. These are material selection/ improvement,
and the design of the composite rods and the steel endfittings.
Rehabilitation of Structures using Composites
More
than 40 percent of the Nation's 575,000 highway bridges are functionally
obsolete or structurally deficient. Because of the prohibitive cost of
replacing all of the sub-standard structures, innovative techniques for
rehabilitating deteriorating structures are needed. One particular type of
innovative technique is the external strengthening of concrete structures
utilizing bonded composite materials. We are working to formulate the effects
of surface preparation of the concrete, constituent (composite, concrete, and
adhesive) type, and concrete strength, on the overall bond strength; and study
the fatigue properties of the (composite material and concrete) bond. In
addition, the effect of severe environment on the bond will be
investigated. These experiments will help to develop a numerical model,
using finite element analysis.
Others
Web
Based Interactive Micromechanical Analysis of Laminated Composites
Web
Based Simulation of Composites Fabrication Processes
Number of Undergraduate
Students (Past and Present) in Research Group: 60
Graduate Students:
Haftay
Hailu (2002)
Samuel
Kidane (2003)
Nikhil
Gupta (Ph.D., 2003)
Amol
Jadhav (2003)
Satish
Kumar Tiwari (2003)
Kiran T. Asokan (2004)
Vikrant
S. Thakare (2004)
Rochell
E. Williams (2005)
Zelalem
Aga (2006)
Naveen Pallempati (2005)
Prashanth
Mahadevan (2006)
Sriram Sunnam (2006)
Phani
Surya Kiran Mylavarapu (Ph.D., 2007)
Paul
Wehmer (2008)
Sameer
Peter (2008)
Narendra Sankella (2008)
Nebiyu Fikru (2009)
Pradeep Chaganti (2009)
Kanakaji Chittineni (2009)
Tiffany
Augustine-Brown (2009)
Chorondalette D. Moore (2009)
Kamissia Stampley (2009)
Jennifer
R. Lee (2009)
Fareed B.
Dawan (Ph.D., 2010)
Rochelle
Williams (Ph.D., 2010)
Kanika
Vessel (Ph.D., 2010)
Ali K. Ghamsari (Ph.D., 2011)
Ephraim
F. Zegeye (Ph.D., 2011)