NWCC Seminar entitled "Propagation of Elastic Waves in Composites and Nanostructures"
|Dates:||12 January 2018|
|Times:||11:00 - 12:00|
|What is it:||Seminar|
|Organiser:||Department of Materials|
|Speaker:||Prof S. Gopalakrishnan|
Propagation of elastic waves is quite complex in laminated composites due to the presence of bending-axial coupling arising due to unsymmetric laminate sequence. The group speeds of the wave can be increased or decreased depending upon the ply-layup sequence.
In this talk, I will introduce the spectral analysis of motion and show how the how this can be used to determine the wave propagation parameters, namely the group speeds and wavenumbers, which can be used to determine the nature of waves propagating in the
medium. The talk will cover wave propagation behavior of both 1-D and 2-D composite waveguides. The talk will then introduce spectral finite element formulation for wave propagation analysis and use this approach to show wave scattering in different waveguides of
increasing complexity, which include determination of Lamb wave modes in composites, where its usage in Structural Health Monitoring
The second part of the lecture will deal with the propagation of elastic waves in nanostructures. Here, I will first introduce gradient elasticity theory, which will then be used to determine the wave parameters, namely the wavenumbers and group speed.
The important aspect of waves in nanostructures is the presence of escape frequency, where the wavenumbers tends to infinity and group speeds tends to zero. Beyond the escape frequency, the propagation of waves stops creating a non-periodic bandgap.
Here, in particular, the wave propagation in single and Multiwall nanotubes and Graphene with or without substrate will be detailed in this talk. Also, a simplified approach to determining the no-local parameter will be presented.
Prof S. Gopalakrishnan
Role: Chair and Professor
Organisation: Indian Institute of Science, Bangalore
Travel and Contact Information
E-Floor Meeting Room, James Lighthill Building