Nonlinear dynamics induced in a structure by seismic and environmental loading

Abstract

In this study, it is shown that under very weak dynamic and quasi-static deformation that is orders of magnitude below the yield deformation of the equivalent stress-strain curve (around 10(-3)), the elastic parameters of a civil engineering structure (resonance frequency and damping) exhibit nonlinear softening and recovery. These observations bridge the gap between laboratory and seismic scales where elastic nonlinear behavior has been previously observed. Under weak seismic or atmospheric loading, modal frequencies are modified by around 1% and damping by more than 100% for strain levels between 10(-7) and 10(-4). These observations support the concept of universal behavior of nonlinear elastic behavior in diverse systems, including granular materials and damaged solids that scale from millimeter dimensions to the scale of structures to fault dimensions in the Earth.

Investigations of elastic vibration periods of reinforced concrete moment-resisting frame systems with various infill walls

“…Even under weak motions, nonlinear response can be observed, i.e. a variation of the elastic properties due to nonlinear elastic phenomena as stated in the study by Guéguen et al [21], or due to atmospheric loading, e.g. temperature or/and wind as stated in the studies by Clinton et al [22], Herak and Herak [23], and Mikael et al [24].…”

Slow dynamics of consolidated granular systems: Multi-scale relaxation

“…[25][26][27][28] Other examples include the co-seismic decrease and subsequent relaxation of the fundamental resonance frequencies of intact buildings. 29 Permeability was also observed to relax after modifications in the effective stress field caused by pore pressure oscillations aimed at, e.g., dynamic permeability enhancement vital for energy recovery applications. 30 The pump strain field is the carefully controlled laboratory realization of the transient, incoherent, elastic noise fields in which many granular media systems are awash, e.g., a formation adjacent to a borehole, a bridge pier, and a segment of a fault system.…”

Nonlinear elasticity in rocks: A comprehensive three-dimensional description

“…NMEMs are not simply a scientific curiosity. Understanding their complex mechanical behavior is a growing need for many applications, including the monitoring of building integrity in civil engineering [4,5], nuclear safety [6,7], bone fragility (e.g., microfractures) [8], the mechanisms of earthquake triggering [9], or the design of novel materials [10].…”