Ultrasonics Numerical Modelling Facilities

Ultrasonics Numerical Modelling Facilities

Numerical modelling remains a vital tool to better understand and validate the measurement process.

As well as enabling reliable predictions to be made, it can also help assist manufacturers with design, prototyping, production, optimisation, quality assurance and rework problems.

The NPL Acoustics Group possesses a suite of numerical modelling tools capable of investigating a broad range of problems.

These include:

PAFEC VibroAcoustics

This finite element and boundary element software enables full fluid/structure interactions and is ideal for field modelling and transducer design. It features piezoelectric capabilities, full electrical, mechanical and acoustical coupling, field calculation of acoustic pressure, intensity and particle velocity. Both continuous wave and transient excitation problems may be investigated.

ANSYS CFX

This high-performance, general purpose fluid dynamics program can be applied to solve wide-ranging fluid flow problems using the finite volume method in the time domain. It is used at NPL on a dedicated 96 GB RAM 12-core workstation. This software can take advantage of multi-core processing. It has the advantage of being able to factor a temperature dependence of media properties.

CyberLogic Wave3000 Plus

This finite difference time domain software produces a solution to the 3D visco-elastic wave equation for full 3D ultrasound simulation. It includes piezoelectric capabilities, models longitudinal and shear propagation in solids and liquids, including mode conversions, as well as the coupled piezo-electric waves. Frequency dependent attenuation (viscous losses) can be accounted for. Infinite (absorbing) boundary conditions can be imposed. This software features multi-processor capabilities.

These tools have been applied across a wide range of problems, including non-destructive evaluation, food processing, diagnostic and therapeutic ultrasound, propagation of ultrasound through soft tissue and bone, piezoelectric transducer design and microchannel modelling. NPL has the facility to create and import arbitrary CAD data into these packages.

Results of FE modelling can be compared with experiment and for compliance with relevant international standards when prototype devices are characterised using NPL's unique acoustic measurement facilities.