Stephen Puplampu is enrolled in the Ph.D. program in the Civil and Environmental Engineering (CEE) Department at the University of Tennessee, Knoxville (UTK). He is a graduate research assistant (GRA) working with Professor Dayakar Penumadu. Mr. Puplampu received his B.S. in Physics from the Kwame Nkrumah University of Science and Technology (KNUST), Ghana, in 2008. Mr. Puplampu started his graduate studies at UTK in the spring of 2012 and focuses on mechanical and microstructural characterization of structural alloys.
Using in-situ neutron diffraction measurements, Mr. Puplampu aspires to better understand the post-yield anisotropic lattice plane response to mechanical loading. The experimental results provide data for validation of crystal plasticity finite element models. He is also collaborating with other scientists on the development of two-dimensional neutron detectors for diffraction measurements. Mr. Puplampu carried out experiments using the Neutron Residual Stress Mapping Facility (NRSF2) instrument at the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory (ORNL) and the E3 instrument at the Helmholtz Zentrum Berlin (HZB) in Berlin, Germany.
Other characterization techniques that Mr. Puplampu uses include digital imaging correlation for strain measurements, X-ray diffraction, and electron backscatter diffraction (EBSD) for microstructure evolution analysis. In addition, he has experience with time-of-flight (TOF) diffraction and small angle scattering (SANS) experiments conducted at ORNL on the VULCAN engineering materials diffractometer at the Spallation Neutron Source (SNS) and the GP-SANS instrument at the HFIR, respectively.
Dr. Penumadu and Mr. Puplampu made use of non-destructive 3D imaging with X-ray and neutron tomography in a collaboration with the late Professor Larry Taylor and his group from the UTK Department of Earth and Planetary Sciences on the study of the internal texture of diamondiferous eclogites. These techniques were also used in the investigation of stress-induced damage in an aluminum alloy of structural interest.