Jentek Sensors, Incorporated

Mark D Windoloski

Neil J Goldfine

Andrew P Washabaugh

Darrell E Schlicker

David C Grundy

Yanko K Sheiretov

Todd M Dunford

Vladimir B Tsukernik

Ian C Shay

Scott A Denenberg

Vladimir A Zilberstein

Robert J Lyons

Stuart D Chaplan

Kevin P Dixon

Saber Bahranifard

Karen E Walrath

Christopher A Craven

Christopher Root

Volker Weiss

Ian C Shav

A measurement system, its assembly and use are disclose. The system may include an instrument for making sensor measurements. The instrument has a substantially cylindrical housing. The shape and size allow the instrument to easily fit in an average hand enabling handheld operation. The housing houses a board stack of electronic boards. These electronics drive an electrical signal in at least one drive channel and measure responses from at least two sensing channels. These responses are provided to a processor for analysis. The instrument has a sensor connector that enables simultaneous electrical and mechanical attachment of an end effector.

Measurement system and method of use

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.

Material condition assessment with eddy current sensors

Methods and apparatus are described for absolute electrical property measurement of materials. This is accomplished with magnetic and electric field based sensors and sensor array geometries that can be modeled accurately and with impedance instrumentation that permits accurate measurements of the in-phase and quadrature phase signal components. A dithering calibration method is also described which allows the measurement to account for background material noise variations. Methods are also described for accounting for noise factors in sensor design and selection of the optimal operating conditions which can minimize the error bounds for material property estimates. Example application of these methods to automated engine disk slot inspection and assessment of the mechanical condition of dielectric materials are presented.

Absolute property measurements using electromagnetic sensors

Combined wound and micro-fabricated winding constructs are described for the inspection of materials and the detection and characterization of hidden features or flaws. These constructs can be configured as sensors or sensor arrays that are surface mounted or scanned over conducting and/or magnetizable test materials. The well-defined geometry obtained micro-fabricated windings and from carefully wound coils with known winding positions permits the use of model based inversions of sensed responses into material properties. In a preferred embodiment, the primary winding is a wound coil and the sense elements are etched or printed. The drive or sense windings can also be mounted under fasteners to improve sensitivity to hidden flaws. Ferrites and other means may be used to guide the magnetic flux and enhance the magnetic field in the test material.

Hybrid wound/etched winding constructs for scanning and monitoring

A set of curved components, such as the dovetail region of engine blades, are inspected by mounting each component into a circular carousel in a vertical orientation and rotating the carousel to move each component toward and away from an inspection site. The inspection site clamps a flexible eddy current sensor array to the curved material surface, scans the array over the surface, records the sensor position. A rigid element having a surface geometry similar to the surface shape of the component can be attached to the component to facilitate scanning of the sensor array over a component edge. The response of each sense element in the array may be converted into an effective material property and sense element proximity to the component material surface to verify the quality of the inspection scan and the presence of a defect such as a crack.

Engine blade dovetail inspection

Local features such as cracks in materials are nondestructively characterized by measuring a response with an electromagnetic sensor and converting this response into a selected property using a database. The database is generated prior to data acquisition by using a model to generate a baseline response or field distribution for the sensor and combining these results with another model, which may be simpler than the first model or provide a local representation of the field perturbations around a feature, which is evaluated multiple times over a range of values of the selected property. In addition, the presence of a feature may be detected by converting the sensor response into a reference parameter, such as a lift-off factor that reflects the sensor position relative to a material edge, and using this parameter to determine a reference response that can be compared to the measured response.

Local feature characterization using quasistatic electromagnetic sensors

Observability of damage precursor, damage and usage states, or event occurrence may be enhanced by modifying component materials to include self-monitoring materials or by processing test material to alter the surface properties. The properties of the self monitoring materials, such as magnetic permeability or electrical conductivity, are monitored with electromagnetic sensors and provide greater property variations with component condition than the original component material. Processing includes shot peening or laser welding.

Self-monitoring metals, alloys and materials

A test circuit having a drive winding with parallel conducting segments and a plurality of sense elements used for the nondestructive measurement of materials. The drive winding segments have extended portions and are driven by a time varying electric current to impose a magnetic field in the test material. Sense elements are distributed in a direction parallel to the extended portions of these drive segments, with separate connections provided to each sense element. A second plurality of sense elements may also be distributed parallel to the extended portions of the drive windings, being either aligned or offset from a first plurality of sense elements.

Test circuit having parallel drive segments and a plurality of sense elements

An apparatus for the nondestructive measurements of materials. Eddy current sensing arrays are described which provide a capability for high resolution imaging of test materials and also a high probabilitity of detection for defects. These arrays incorporate layouts for the sensing elements which take advantage of microfabrication manufacturing capabilities for creating essentially identical sensor arrays, aligning sensing elements in proximity to the drive elements, and laying out conductive pathways that promote cancellation of undesired magnetic flux.

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Burlington, MA, United States of America

Mark D Windoloski