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Optical Measurement of In-plane Waves in Mechanical Metamaterials Through Digital Image Correlation

View Article: PubMed Central - PubMed

ABSTRACT

We report on a Digital Image Correlation-based technique for the detection of in-plane elastic waves propagating in structural lattices. The experimental characterization of wave motion in lattice structures is currently of great interest due its relevance to the design of novel mechanical metamaterials with unique/unusual properties such as strongly directional behaviour, negative refractive indexes and topologically protected wave motion. Assessment of these functionalities often requires the detection of highly spatially resolved in-plane wavefields, which for reticulated or porous structural assemblies is an open challenge. A Digital Image Correlation approach is implemented that tracks small displacements of the lattice nodes by centring image subsets about the lattice intersections. A high speed camera records the motion of the points by properly interleaving subse- quent frames thus artificially enhancing the available sampling rate. This, along with an imaging stitching procedure, enables the capturing of a field of view that is sufficiently large for subsequent processing. The transient response is recorded in the form of the full wavefields, which are processed to unveil features of wave motion in a hexagonal lattice. Time snapshots and frequency contours in the spatial Fourier domain are compared with numerical predictions to illustrate the accuracy of the recorded wavefields.

No MeSH data available.


Time snapshots of the recorded wave motion in the lattice resulting from the DIC process presented at t = 3.78 ms (left) and t = 3.99 ms (right).Horizontal x component (a,b), vertical y component (c,d).
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f5: Time snapshots of the recorded wave motion in the lattice resulting from the DIC process presented at t = 3.78 ms (left) and t = 3.99 ms (right).Horizontal x component (a,b), vertical y component (c,d).

Mentions: The recorded motion of the lattice can be represented in the form of the time snapshots in Fig. 5, where the colour code is associated with the resultant of the in-plane displacement components.


Optical Measurement of In-plane Waves in Mechanical Metamaterials Through Digital Image Correlation
Time snapshots of the recorded wave motion in the lattice resulting from the DIC process presented at t = 3.78 ms (left) and t = 3.99 ms (right).Horizontal x component (a,b), vertical y component (c,d).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5304329&req=5

f5: Time snapshots of the recorded wave motion in the lattice resulting from the DIC process presented at t = 3.78 ms (left) and t = 3.99 ms (right).Horizontal x component (a,b), vertical y component (c,d).
Mentions: The recorded motion of the lattice can be represented in the form of the time snapshots in Fig. 5, where the colour code is associated with the resultant of the in-plane displacement components.

View Article: PubMed Central - PubMed

ABSTRACT

We report on a Digital Image Correlation-based technique for the detection of in-plane elastic waves propagating in structural lattices. The experimental characterization of wave motion in lattice structures is currently of great interest due its relevance to the design of novel mechanical metamaterials with unique/unusual properties such as strongly directional behaviour, negative refractive indexes and topologically protected wave motion. Assessment of these functionalities often requires the detection of highly spatially resolved in-plane wavefields, which for reticulated or porous structural assemblies is an open challenge. A Digital Image Correlation approach is implemented that tracks small displacements of the lattice nodes by centring image subsets about the lattice intersections. A high speed camera records the motion of the points by properly interleaving subse- quent frames thus artificially enhancing the available sampling rate. This, along with an imaging stitching procedure, enables the capturing of a field of view that is sufficiently large for subsequent processing. The transient response is recorded in the form of the full wavefields, which are processed to unveil features of wave motion in a hexagonal lattice. Time snapshots and frequency contours in the spatial Fourier domain are compared with numerical predictions to illustrate the accuracy of the recorded wavefields.

No MeSH data available.