Method and Apparatus for Non-Destructive Evaluation of Materials

Methods and apparatus for characterizing composite materials for manufacturing quality assurance (QA), periodic inspection during the useful life, or for forensic analysis/material testing. System are provided that relate eddy-current sensor responses to the fiber layup of a composite structure, the presence of impact damage on a composite structure with or without a metal liner, volumetric stress within the composite, fiber tow density, and other NDE inspection requirements. Also provided are systems that determine electromagnetic material properties and material dimensions of composite materials from capacitive sensor inspection measurements. These properties are related to the presence of buried defects in non-conductive composite materials, moisture ingress, aging of the material due to service or environmental/thermal exposure, or changes in manufacturing quality

Material condition assessment with eddy current sensors

Eddy current sensors and sensor arrays are used for process quality and material condition assessment of conducting materials. In an embodiment, changes in spatially registered high resolution images taken before and after cold work processing reflect the quality of the process, such as intensity and coverage. These images also permit the suppression or removal of local outlier variations. Anisotropy in a material property, such as magnetic permeability or electrical conductivity, can be intentionally introduced and used to assess material condition resulting from an operation, such as a cold work or heat treatment. The anisotropy is determined by sensors that provide directional property measurements. The sensor directionality arises from constructs that use a linear conducting drive segment to impose the magnetic field in a test material. Maintaining the orientation of this drive segment, and associated sense elements, relative to a material edge provides enhanced sensitivity for crack detection at edges

MONITORING DIFFUSION COATING AGING WITH MULTI-FREQUENCY EDDY CURRENT MWM SENSORS

ABSTRACT Diffusion coatings are widely used to protect hot gas path components in land-based gas turbines and jet engines. Effective nondestructive assessment of the aged coating and substrate condition is critical for support of refurbish/ replace/run decisions. In this paper, we present results on aging characterization of nickel aluminide and platinum aluminide coatings. The measurements were performed using a Meandering Winding Magnetometer (MWM ® ) eddy current sensor over a wide range of frequencies. Single-channel MWM sensors and multichannel imaging MWM-Arrays permit tracking of features of interest for a population of components and provide new capabilities for inspecting gas turbine components. These conformable sensors allow convenient manual and automated inspection on complex surfaces. Results on coating aging assessment suggest that the multiple frequency MWM technique can be implemented for characterization of diffusion coatings and base metals before and after component refurbishment