Concrete is a ubiquitous building material with an extensive history, yet it has notable limitations. Its sizeable environmental impact, low tensile to compressive strength ratio, and lack of durability leave room for innovation. Concrete durability frames the motivation for this research. This paper presents the motivation, methods, and findings of tests performed to quantify the durability of concrete reinforced with automatically shrinking, chitosan-based fibers. A literature review, the procedures used for synthesizing chitosan fibers, and preliminary tests of the control fibers are all discussed. Durability is characterized with a rapid freezing and thawing test. Freeze-thaw damage is a recurrent form of weathering and is a significant cause of concrete damage. From the freeze-thaw test, 1 wt% shrinking (active) fiber reinforced concrete had a 198.3% average increase in durability factor over non-shrinking (passive) fiber reinforced concrete and a 251.4% average increase over non-reinforced concrete.

This study will report on the characterization of strain fields through DIC in Ni2MnGa alloys under combined tensile and magnetic loading. The DIC approach allows us to observe the evolution of the strain field over the entire sample, concurrent with the evolution of the twin microstructure of the sample, providing a more comprehensive insight on material behavior than traditional strain measurement techniques. Preliminary results confirm that the strain field, during quasi-static tensile loading, is highly dependent on the nature of the sample microstructure (coarse or fine twin microstructure), and that pinning sites exist along the sample despite being a single crystal sample. The knowledge obtained from this study can be used to expand the realm of MSMA based applications, and to improve constitutive model predictions by accurately predicting the tensile response of the material.

An accurate and computationally efficient non-linear magnetostrictive constitutive model is required to properly develop novel magnetostrictive technologies. While the authors have recently shown exact analytical solutions are available for one-dimensional constitutive models built with statistical mechanics, there are currently no known closed form three-dimensional solution. Instead, this presentation will evaluate the use of several different approximation techniques in a three-dimensional model including: Laplace’s method, series expansions, and multivariate spline interpolation. We will show the conditions under which each approximation is numerically accurate and present a model that maintains numerical accuracy over a wide range of applied fields and stresses.

This study aims to compare all MSMA power harvester studies reported to date and identify which design(s) yield highest power and efficiency. The study considers the location of the coil as the main differentiator of the reported designs and starts by generating open circuit voltage with a coil around the MSMA and a biaxial biased magnetic field. The experimental results obtained were compared with the results reported for other power harvesting systems, by normalizing the results with respect to experimental parameters like frequency, number of turns of the pickup coil, cross-sectional area of the pickup coil and sample size. Normalized experimental parameters were then used to calculate and compare the maximum electrical power output of the various power harvesting systems. Results suggest that the side coil setup produces a higher power as compared to the surrounding coil setup. This is primarily because, under the magneto-mechanical loading conditions specific to power harvesting, the maximum change in the MSMAs’ magnetization and correspondingly the largest change in magnetic flux density occurs across its thickness not along its length.