Determining ultrasonic propagation effective properties in complex heterogeneous media through microstructure-scale simulation (original) (raw)

3-D Image-Based Simulation for Ultrasonicwave Propagation in Heterogeneous and Anisotropic Materials

2011

Time domain simulation tools for ultrasonic wave propagation in a target material with a complex outer surface or various inclusions are developed by combining the finite integration technique (FIT) and the finite element method (FEM) with an image-based modeling. In our simulation, the geometry of the target is determined by a digital image such as X-ray picture, CAD data, etc. and the processed voxel data is directly fed into the numerical calculation with the FIT or FEM. The accuracy of the two methods is discussed by comparison with the boundary element method. A simulation of the ultrasonic testing for a concrete material is shown with the 3-D image-based FIT.

Explicit finite element simulation of ultra-sound propagation in engineering components

Traditionally, elastic wave propagation through solid media has been studied analytically, and for various special cases where simplification assumptions can be made. Particular cases include the work of the classical physicists, such as Rayleigh and Lamb, and lead to the development of better understanding of earthquakes and deductions about the structure of the Earth's core. It also provides the theoretical basis for the Hopkinson Bar high strain-rate material test methodology. More recently ultrasound has become an everyday tool for medical imaging, and non-destructive evaluation (NDE) of engineering components. In order to utilize these techniques, it is necessary to infer information about the internal structure of a volume of material based on the ultrasound signal applied, and the resulting signals received at various locations. This is a particular issue with heterogeneous materials, since changes in density and material stiffness give rise to reflections and refractions. In these modern times of increasing computational power, it is now within the realm of possibility to run explicit finite element analyses with element sizes significantly smaller than a typical ultrasound wavelength, smaller than 1mm. Using explicit finite element analysis the propagation of ultrasound through a material volume with internal features such as flaws or cracks can be visualized.

Numerical simulation of ultrasonic tomography inspections of highly heterogeneous materials

IOP Conference Series: Materials Science and Engineering, 2012

This paper deals with the simulation of ultrasonic transmission tomography systems in water-immersed to nondestructively inspect highly heterogeneous materials with fractures. The time-domain Elastodynamic Finite Integration Technique (EFIT) was employed for all numerical simulations because is able to reliably simulate this type of ultrasonic problems. The EFIT code was implemented using OpenCL and PyOpenCL. Several ultrasonic tomography inspection setups were numerically simulated under different conditions varying the number of ultrasonic sources and their size and number and different operation schemes. Sinograms of concrete scenarios were computed and compared for each configuration, using homogeneous materials with similar fracture types and experimentally validated.

Finite element analysis simulations for ultrasonic array NDE inspections

2016

Advances in manufacturing techniques and materials have led to an increase in the demand for reliable and robust inspection techniques to maintain safety critical features. The application of modelling methods to develop and evaluate inspections is becoming an essential tool for the NDE community. Current analytical methods are inadequate for simulation of arbitrary components and heterogeneous materials, such as anisotropic welds or composite structures. Finite element analysis software (FEA), such as PZFlex, can provide the ability to simulate the inspection of these arrangements, providing the ability to economically prototype and evaluate improved NDE methods. FEA is often seen as computationally expensive for ultrasound problems however, advances in computing power have made it a more viable tool. This paper aims to illustrate the capability of appropriate FEA to produce accurate simulations of ultrasonic array inspectionsminimizing the requirement for expensive test-piece fabrication. Validation is afforded via corroboration of the FE derived and experimentally generated data sets for a test-block comprising 1D and 2D defects. The modelling approach is extended to consider the more troublesome aspects of heterogeneous materials where defect dimensions can be of the same length scale as the grain structure. The model is used to facilitate the implementation of new ultrasonic array inspection methods for such materials. This is exemplified by considering the simulation of ultrasonic NDE in a weld structure in order to assess new approaches to imaging such structures.

Ultrasonic Assessment of Metal Microstructures, Modelling and Validation

2016

The uniformity of strip rolled steel and its mechanical properties are intrinsically linked to the complex microstructure along the strip length. Ultrasonic methods are sensitive to differences in grain size, grain distribution and texture. This with the intention to provide suitable tools to inline monitors the properties of hot rolled steel. In this paper, we present a comparison of results from numerical and analytical simulations of the elastic wave propagation in deterministic and stochastic models of the microstructures. Modelled microstructures are used to provide the flexibility of assessing single microstructural parameters of different steel grades and rolling conditions. The individual simulations are validated against laser ultrasonic measurements on metal sheets in thickness range of 2mm-5mm, which were independently characterized metallurgically. The correlation to parameters as texture, grain size and dual phase composition was addressed. The simulation facilitates th...

Validation of Ray-Based Ultrasonic Simulation Tool ( Simsonic ) with Measurements

2011

A ray-based simulation software with 2D and 3D ray model is developed to study the propagation of ultrasonic waves in solids. SIMSONIC accepts any geometry that can be modelled in CAD software in SLP and STL file formats. The ultrasonic beam is modelled as a collection of rays and a cumulative Gaussian distribution is used to distribute the energy. The rays are propagated and new reflected & refracted rays are generated at each interface following Snell’s law and Mode conversions. In this paper, the features of SIMSONIC are presented along with comparison of B-scans of the SIMSONIC with measurements. All the measurements are carried out with an 3.5 MHz unfocussed transducer in the immersion mode for normal incidence, P-wave and S-wave inspection. The measurement reported in QNDE 2006 Ultrasonic Benchmarks for Rectangular defects (RD) is also used to validate SIMSONIC and is presented in this paper. The A-scans and the associated B-scans show good agreement with measurements.

High performance ultrasonic field simulation on complex geometries

2016

Ultrasonic field simulation is a key ingredient for the design of new testing methods as well as a crucial step for NDT inspection simulation. As presented in a previous paper [1], CEA-LIST has worked on the acceleration of these simulations focusing on simple geometries (planar interfaces, isotropic materials). In this context, significant accelerations were achieved on multicore processors and GPUs (Graphics Processing Units), bringing the execution time of realistic computations in the 0.1 s range. In this paper, we present recent works that aim at similar performances on a wider range of configurations. We adapted the physical model used by the CIVA platform to design and implement a new algorithm providing a fast ultrasonic field simulation that yields nearly interactive results for complex cases. The improvements over the CIVA pencil-tracing method include adaptive strategies for pencil subdivisions to achieve a good refinement of the sensor geometry while keeping a reasonable number of ray-tracing operations. Also, interpolation of the times of flight was used to avoid time consuming computations in the impulse response reconstruction stage. To achieve the best performance, our algorithm runs on multi-core superscalar CPUs and uses high performance specialized libraries such as Intel Embree for ray-tracing, Intel MKL for signal processing and Intel TBB for parallelization. We validated the simulation results by comparing them to the ones produced by CIVA on identical test configurations including mono-element and multiple-element transducers, homogeneous, meshed 3D CAD specimens, isotropic and anisotropic materials and wave paths that can involve several interactions with interfaces. We show performance results on complete simulations that achieve computation times in the 1s range.

Quantitative studies in ultrasonic wave-defect interaction

Ultrasonics, 1987

A common aim of ultrasonic inspections is to detect, locate, size and characterize defects in a wide range of structures. The current range of ultrasonic techniques uses a limited amount of the available information. To improve existing techniques in this respect, a fundamental understanding of elastic wave propagation and its interaction with defects is required. In this study ultrasonic Rayleigh waves are modelled numerically using explicit finite difference methods. These models, which are part of a group of computer models named 'USWAPS' (UltraSonic WAve Propagation and Scattering), are used to study the various geometries of interest.

Relation between ultrasonic scattering and microstructure of polycrystalline materials

Journal of Physics: Conference Series, 2011

Ultrasonic testing is a very common volumetric technique used in industry in order to detect and characterized defects. Within the framework of the maintenance of its nuclear power stations, Electricité de France (EDF) uses this technique on various components. In the case of polycrystalline materials, the scattering of the ultrasonic wave can result in an important attenuation of the signal and the appearance of structural noise. In the present study, we propose to analyze scattering noise in relation to the microstructure of the material. Both experimental and 2D finite elements modelling results are presented for different controlled structure of an homogeneous and isotropic Ni-based alloy.