The nonlinear acoustic applications for material characterization are reviewed. The general theoretical analysis of the effects of nonlinearity, dissipation, dispersion, and diffraction on intense ...

Review / Sythèse Nonlinear acoustic applications for material characterization: A review

The nonlinear acoustic applications for material characterization are reviewed. The general theoretical analysis of the effects of nonlinearity, dissipation, dispersion, and diffraction on intense acoustic-wave propagation is given. Acoustic nonlinear parameters and their determination methods are introduced. The investigations of nonlinear acoustic applications for solid material evaluation are discussed for different levels of disruption, from asymmetry of lattice structure and dislocation in crystals to disbonds and cracks in engineering materials. The experimental methods involved in these investigations are also considered. The techniques used for nonlinear acoustic imaging are divided into two categories, concerned with resolution improvement by using higher harmonics, and nonlinear parametric imaging. The nonlinear acoustic applications in biomedical imaging, acoustic microscopy, and nonlinear nondestructive evaluation are presented. Finally, the issues that need further investigations in this area are discussed.

Nonlinear acoustic applications for material characterization: A review

The nature and underlying rationale of the acousto-ultrasonic approach is reviewed, needed advanced signal analysis and evaluation methods suggested, and application potentials discussed. Acousto-ultrasonics is an NDE technique combining aspects of acoustic emission methodology with ultrasonic simulation of stress waves. This approach uses analysis of simulated stress waves for detecting and mapping variations of mechanical properties. Unlike most NDE, acousto-ultrasonics is less concerned with flaw detection than with the assessment of the collective effects of various flaws and material anomalies. Acousto-ultrasonics has been applied chiefly to laminated and filament-wound fiber reinforced composites. It has been used to assess the significant strength and toughness reducing effects that can be wrought by combinations of essentially minor flaws and diffuse flaw populations. Acousto-ultrasonics assesses integrated defect states and the resultant variations in properties such as tensile, shear, and flexural strengths and fracture resistance. Matrix cure state, porosity, fiber orientation, fiber volume fraction, fiber-matrix bonding, and interlaminar bond quality are underlying factors.

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The Acousto-Ultrasonic Approach

The design, construction and application of a large aperture lens-less line-focus PVDF transducer

Current research addresses ultrasonic quality sensor utilisation for inline cure monitoring, to control and analyse compression moulding In this investigation, an ultrasonic impulse transmission method was applied to directly monitor changes in the mechanical properties of moulding compounds throughout the whole cure cycle These measurements were performed during the processing using transducers which were designed to operate at elevated temperature and pressure in a compression mould Measurements of ultrasound velocity and variation of attenuation coefficient of longitudinal waves were performed following the cure cycle Ultrasonic measurements were used to investigate the influence of different types of moulding compounds, artificial weathering at elevated temperatures, filler volume, moisture content as well as amount of hardener on the curing process

Process monitoring of moulding compounds by ultrasonic measurements in a compression mould

X-Ray Diffraction and Neutron Scattering Techniques.- X-Rays for Non-Destructive Characterization of Materials Properties.- Application of a Position Sensitive Scintillation Detector to Nondestructive X-Ray Diffraction Characterization of Metallic Components.- Residual Stress Measurements in Ti-6Al-4V and ?-Brass with Sub-Surface Flaws Using X-Ray Diffraction Techniques.- Determination of Residual Stress from Two-Dimensional Diffraction Patterns.- Small Angle Neutron Scattering: An NDE Tool.- Eddy Current and Electrical Conductivity Applications.- Prediction of Laser Irradiated Surface Properties by Eddy Current Method.- Solving for Thermal History and Metallurgical Condition of a Quenched and Aged Aluminum Alloy Through Conductivity and Hardness Properties.- Eddy Current Measurement of Residual Stresses in a Heavy Section Steel Weldment.- Magnetic, Ultrasonic, and Analytical Techniques for Stress and Cold Work Indication.- Solving Internal Stress Measurement Problems by a New Magnetoelastic Method.- Nondestructive Determination of Residual and Applied Stress by Micro-Magnetic and Ultrasonic Methods.- The Need for Analytical/Experimental Orchestrated Approaches to Solve Residual Stress Problems in Real Structures.- Internal Friction of Fe-Based Binary Alloys at High Frequency.- General Ultrasonic Considerations and Applications.- The Inverse Problem in Materials Characterization Through Ultrasonic Attenuation and Velocity Measurements.- Inference of Fatigue Crack Closure Stresses from Ultrasonic Transmission Measurements.- Inference of Compressive Stresses at Joined Interfaces Using Ultrasonic Reflectivity.- Frequency Dependent Properties of Materials Containing a Distribution of Pores and/or Inclusions.- Measurement of Thin Case Depth in Hardened Steel by Untrasonic Pulse-Echo Angulation Techniques.- Ultrasonic Micro Structural Characterization of Crystalline Metals.- Acoustic Emission for In-Process Monitoring and Microstructure Control?.- Use of Ultrasonic Techniques to Assess the Mechanical Properties of Steels.- Determination of Microstructural Parameters by Magnetic and Ultrasonic Quantitative NDE.- Microstructural Characterization of Titanium by Acoustic Microscopy.- Ultrasonic Characterization of Titanium 6211 Weldments.- Measurement of Near-Surface Ultrasonic Absorption by Thermo-Emissivity.- Ultrasonic Characterization of Amorphous Metals, Polymers, and Composites.- Ultrasonic Materials Characterization of Melt Spun Metallic Ribbons.- Application of Ultrasonic Technique to Cure Characterization of Epoxies.- Ultrasonic Measurements of Elastic Moduli of Thermally Cycled Metal Matrix Composite Precursor Wires.- Acousto-Elastic Effect of Stress in Aluminum and Steel.- Effects of Rolled Plate Thickness on Anisotropy, with Application to Acoustic Stress Measurement.- Ultrasonic Shear Wave Measurements of Known Residual Stress in Aluminum.- Rayleigh Wave Measurement of Surface Stresses in Stainless Steel Piping.- Acousto-Elastic Effects in Two Structural Steels.- Relationship Between Stress and Temperature Dependence of Ultrasonic Shear Velocity.- Author Index.

Robert E. Green

Papers

Nondestructive methods for material property determination