Anisotropic Medium for Oblique Elastic Wave Transmission

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Solution Overview

Problem

Conventional full transmission technologies are limited to single-mode cases like electromagnetic or sound waves and are only applicable to normal incidence, failing to achieve 100% energy efficiency for obliquely incident elastic waves, which are crucial in nondestructive testing and medical ultrasonic applications.

Innovation Solution

An anisotropic medium is designed to fully transmit obliquely incident elastic waves by satisfying phase matching and polarization matching conditions, using an elastic metamaterial with a slit structure that includes specific design variables, allowing for both mode-preserving and mode-converting full transmission of longitudinal and shear waves.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional full transmission technology (Fabry-Perot resonance or impedance matching) is used, then full transmission can be achieved for normal incidence waves, but it cannot handle oblique incidence elastic waves with both longitudinal and shear modes

Engineering Contradiction:

Improveapplicability to oblique incidence elastic wavesVSAvoidfull transmission condition satisfaction

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent transforms the isotropic medium into an anisotropic medium by introducing directional dependence in material properties. This allows the medium to satisfy both phase matching and polarization matching conditions simultaneously for obliquely incident elastic waves, enabling full transmission of both longitudinal and shear modes that conventional isotropic media cannot achieve

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs composite material structures with specific anisotropic properties to create a medium that can independently control phase and polarization of elastic waves. The composite structure enables simultaneous satisfaction of multiple transmission conditions for complex elastic wave modes, overcoming the limitations of single-material conventional approaches

Inventive Principle:

Principle #40Composite materials

2Loss of energy

If a single-layered medium is inserted for full transmission, then transmission efficiency improves for normal incidence, but reflection cannot be blocked for oblique incidence elastic waves

Engineering Contradiction:

Improvewave reflection lossVSAvoidhandling of multi-mode elastic waves

Core Design Contradiction:

Loss of energyVSAdaptability or versatility

Solution Approach 1:

By changing the material parameters from isotropic to anisotropic, the patent enables the medium to independently control phase velocity and polarization direction. This allows the single-layered anisotropic medium to block reflections for oblique incidence elastic waves while maintaining full transmission capability for both longitudinal and shear modes

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The anisotropic medium acts as an intermediary layer between incident and transmission media, transforming the multi-mode oblique incidence elastic waves through phase and polarization matching. This intermediary transformation enables full transmission by converting incident waves into transmitted waves that satisfy boundary conditions, preventing reflection losses

Inventive Principle:

Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The anisotropic medium achieves 100% transmittance of obliquely incident elastic waves, significantly improving the efficiency of nondestructive testing, medical ultrasonic treatments, and other applications by eliminating reflections and enhancing wave transmission quality.

Implementation Method 1

the full transmission condition includes a phase matching condition based on a wavenumber relationship of an eigenmode in the anisotropic medium

Methodology Applied

Scientific EffectPhase matching:

Implementation Method 2

a polarization matching condition based on a relationship between a polarization vector and an amplitude of the eigenmode

Methodology Applied

Scientific EffectPolarization matching: Polarisation

Data Source

PatentUS11448786B2Anisotropic media for full transmission of obliquely incident elastic waves

Publication Date: 2022.09.20 CENT FOR ADVANCED META MATERIALS

AI summary

An exemplary embodiment of the present invention provides an anisotropic medium for full transmission of obliquely incident elastic waves considering a longitudinal wave and a shear wave by using an anisotropic medium designed to fully transmit elastic waves in a desired mode when elastic waves are obliquely incident to a boundary of different media. The anisotropic medium for fully transmitting an obliquely incident elastic wave according to an exemplary embodiment of the present invention includes: an incident medium to which an incident elastic wave including a longitudinal wave and a shear wave, and being obliquely incident with a predetermined incidence angle, is incident and reflected; a transmission medium to which a transmitting elastic wave including a longitudinal wave and a shear wave is transmitted; and an anisotropic medium, installed between the incident medium and the transmission medium, for blocking reflection of a predetermined reflecting elastic wave as a predetermined full transmission condition is satisfied, and fully transmitting a transmitting elastic wave in a predetermined type of full transmission, wherein the full transmission condition includes a phase matching condition based on a wavenumber relationship of an eigenmode in the anisotropic medium, and a polarization matching condition based on a relationship between a polarization vector and an amplitude of the eigenmode.