Infrastructure Education Using the Impacts of Extreme Storms as Case Studies

Our university will begin offering a freshman level course titled “Introduction to Infrastructure” in Spring 2015. A common complaint from students over the years has been that they do not have a good understanding of what civil and environmental engineering is, and what civil engineers do. One of the goals of this course is to provide students with an early exposure to the practice of civil engineering and its importance to society. Our hope is that this will provide freshman with a solid context within which to continue their studies and motivate them to continue in the program. To this end, the primary goal of the course is to introduce freshmen civil and environmental engineers to civil infrastructure. Additionally, given the current state of infrastructure in the United States, the development of this course is of particular importance to the education and development of future engineers Our course will be a 2-credit lecture course consisting of two 75-minute periods per week of about 40 students per section. It will include sections on structural systems, foundations,transportation systems, water and environmental systems, as well as a general overview of the state of infrastructure in the US, along with other topics discussed in this report. Throughout the course, we will emphasize how the quality of infrastructure directly affects the economy and security of the US, and that the next generation of civil and environmental engineers needs to be more skilled and more able to design and create sustainable infrastructure. A significant emphasis will be placed on the impacts of extreme storms on water infrastructure and the impacts of storm surge and flooding on other infrastructure. We believe the emphasis on the impacts of extreme events on civil infrastructure, and water’s impacts on civil infrastructure in general, will provide a strong point of interest with students. It is likely this interest will be even greater at our university because a majority of our students were either directly or indirectly affected by a recent extreme storm event. Additionally, as the impacts of climate change have become measurable and as climate change projections suggest increased frequency and intensity of extreme events, the need to account for climate change in design for infrastructure is becoming more clearly recognized. A fact that is vital to increase reliability and decrease the nation’s risk and vulnerability to the failure of infrastructure in the future. Finally, we are hoping that the emphasis on extreme storms will help us highlight the connection of all civil infrastructure by providing students with a unifying context

Nonlinear resonances and energy transfer in finite granular chains

In the present work we test experimentally and compute numerically the stability and dynamics of harmonically driven monoatomic granular chains composed of an increasing number of particles N(N=1-50). In particular, we investigate the inherent effects of dissipation and finite size on the evolution of bifurcation instabilities in the statically compressed case. The findings of the study suggest that the nonlinear bifurcation phenomena, which arise due to finite size, can be useful for efficient energy transfer away from the drive frequency in transmitted waves

A mechanical autonomous stochastic heat engine

Stochastic heat engines are devices that generate work from random thermal motion using a small number of highly fluctuating degrees of freedom. Proposals for such devices have existed for more than a century and include the Maxwell demon and the Feynman ratchet. Only recently have they been demonstrated experimentally, using e.g., thermal cycles implemented in optical traps. However, the recent demonstrations of stochastic heat engines are nonautonomous, since they require an external control system that prescribes a heating and cooling cycle, and consume more energy than they produce. This Report presents a heat engine consisting of three coupled mechanical resonators (two ribbons and a cantilever) subject to a stochastic drive. The engine uses geometric nonlinearities in the resonating ribbons to autonomously convert a random excitation into a low-entropy, nonpassive oscillation of the cantilever. The engine presents the anomalous heat transport property of negative thermal conductivity, consisting in the ability to passively transfer energy from a cold reservoir to a hot reservoir

Frequency bands of strongly nonlinear homogeneous granular systems

Recent numerical studies on an infinite number of identical spherical beads in Hertzian contact showed the presence of frequency bands [ Jayaprakash, Starosvetsky, Vakakis, Peeters and Kerschen Nonlinear Dyn. 63 359 (2011)]. These bands, denoted here as propagation and attenuation bands (PBs and ABs), are typically present in linear or weakly nonlinear periodic media; however, their counterparts are not intuitive in essentially nonlinear periodic media where there is a complete lack of classical linear acoustics, i.e., in “sonic vacua.” Here, we study the effects of PBs and ABs on the forced dynamics of ordered, uncompressed granular systems. Through numerical and experimental techniques, we find that the dynamics of these systems depends critically on the frequency and amplitude of the applied harmonic excitation. For fixed forcing amplitude, at lower frequencies, the oscillations are large in amplitude and governed by strongly nonlinear and nonsmooth dynamics, indicating PB behavior. At higher frequencies the dynamics is weakly nonlinear and smooth, in the form of compressed low-amplitude oscillations, indicating AB behavior. At the boundary between the PB and the AB large-amplitude oscillations due to resonance occur, giving rise to collisions between beads and chaotic dynamics; this renders the forced dynamics sensitive to initial and forcing conditions, and hence unpredictable. Finally, we study asymptotically the near field standing wave dynamics occurring for high frequencies, well inside the AB