A transformation elasticity based device for wavefront manipulation. (March 2019)

• Record Type: Journal Article
• Authors: Kuchibhatla, Sai Aditya Raman; Rajagopal, Prabhu
• Is Part Of: NDT & E international. Volume 102(2019)
• Page Start: 304
• Page End: 310
• Publication Date: 2019-03
• Subjects: Transformation elasticity -- Metamaterial plate -- Wave manipulation -- GRIN PC -- Guided waves; Nondestructive testing -- Periodicals; Contrôle non destructif -- Périodiques; Electronic journals; 620.1127
• DOI: 10.1016/j.ndteint.2019.01.006
• Languages: English
• ISSNs: 0963-8695

Abstract

Abstract: The authors propose a metamaterial plate made of gradient refractive index phononic crystals for manipulation of the wavefront of propagating elastic waves in solid media. A square unit cell with through holes is considered as the basis for the proposed metematerial. Guidance on the design of the hole pattern and the choice of materials is obtained with the aid of transformation elasticity principles. Manipulation of a plane wavefront into a cylindrical wavefront is first observed through Finite Element simulations at low frequency (100 kHz), and then practically demonstrated through experiments. Wave propagation with and without the holey region is compared and possible applications at higher frequencies are discussed. Highlights: Metamaterial plate for wavefront manipulation is proposed. Use of transformation elasticity for design of proposed plate is demonstrated. Experiments demonstrating the approach at low frequency are presented. Design for high frequency is studied in finite element simulations. Practical results are compared with analytically expected results.