Multi-scale damage state estimation in composites using nonlocal elastic kernel: An experimental validation

Abstract

a b s t r a c tIn recent years early detection of structural damage (detecting incubation of damage) has received great attention in the structural health monitoring field. However, extraction of lower scale information to quantify the degree of damage is a challenging task, especially when the detection is based on macroscale acoustic wave signals. All materials exhibit dependence on the intrinsic length scale. An attempt is made in this paper to extract lower scale feature from the macro-scale wave signal using nonlocal elasticity theory. The Christoffel solution has been modified using nonlocal parameters. The dispersion curves are generated for anisotropic solids using perturbation parameter through nonlocal theory. Dispersion curves are sensitive to initiation of damage in anisotropic solids at the intrinsic-length scale. In this paper detection of initiation of damage in a 4 mm carbon composite plate is demonstrated by employing nonlocal perturbation parameter and formulating a new Nonlocal Damage Index (NDI). The nonlocal theory is used to demonstrate the early prediction of failure of the system and to show progressive evolution of the damage.

Integral structural health and load monitoring of a helicopter tail boom manufactured from aluminum sheet metal with support from frames and stringers by guided ultrasonic waves

“…The materials dynamic softening and geometrical stiffening by applied stress, both observed for Lamb waves, represent novel effects concerning SHM. The here reported results are part of developments and respected applications based on TOF monitoring for structural health and load monitoring [3][4][5][6][7]). …”

Peridynamics review

“…It is noted that PD has been used for mesoscale fracture analysis in aggregate materials, specifically in multiphase cementitious composites [102]. Shelke et al [103] addressed the multiscale estimation of damage in composite materials by means of a non-local elastic kernel. For more details on the application of PD in the context of multiscale modeling, see [104] among others.…”

Nonlocal Damage Mechanics for Quantification of Health for Piezoelectric Sensor

“…The changes in time of flight of the SAW due to perturbation in surface material properties were determined using cross-correlation technique. Shelke et al have shown that such small differences in TOF (>10 ns) can be obtained using cross-correlation where the sampling rate of the signal is significantly high [50]. Referring to the experimental results (Section 4), the TOF of the first arrival is determined using the cross-correlation technique applied to the time history obtained from the relationship considering piezo and non-piezo stiffening for slow transversal and longitudinal waves velocity, respectively.…”