Jentek Sensors, Incorporated

Andrew P Washabaugh

Neil J Goldfine

Darrell E Schlicker

David C Grundy

Vladimir A Zilberstein

Ian C Shay

Robert J Lyons

Yanko K Sheiretov

Karen E Walrath

Vladimir B Tsukernik

Mark D Windoloski

Volker Weiss

Todd M Dunford

Zachary Michael Thomas

Christopher A Craven

Scott A Denenberg

Markus Zahn

Christopher T Martin

David A Jablonski

Wayne D Ryan

Christopher Root

David C Clark

Don Straney

Mark Windoloski

J Timothy Lovett

Floyd W Spencer

William M Chepolis

Brian L Manning

Leandro M Lorilla

James M Fisher

Ian C Shav

Vladimir Tsukemik

Eric Hill

Alexander V Mamishev

Brian Manning

A system and method are disclosed for enhancing pit detection and sizing in a test object. Response signatures are created and stored in a signature library to characterize various sensor responses (liftoff, orientation) and pit properties (e.g., depth, width), possibly with or without additional considerations (e.g., edges, cracks). A sensor is placed on and scanned across a surface of interest on the test object. During scanning the sensor is measured repeatedly at regular intervals. An encoder may be used to record the sensor position for each measurement. The measurement results are then correlated with one or more signatures in the signature library. A threshold is used to determine if the correlation is indicative of the detection of a pit. If so additional processing may be performed to estimate pit properties.

System and method for pit detection and sizing

System and method for characterizing material condition. The system includes a sensor, impedance instrument and processing unit to collect measurements and assess material properties. A model of the system may be used to enable accurate measurements of multiple material properties. A cylindrical model for an electromagnetic field sensor is disclosed for modeling substantially cylindrically symmetric material systems. Sensor designs and data processing approaches are provided to focus the sensitivity of the sensor to localize material conditions. Improved calibration methods are shown. Sizing algorithms are provided to estimate the size of defects such as cracks and corrosion. Corrective measures are provided where the actual material configuration differs from the data processing assumptions. Methods are provided for use of the system to characterize material condition, and detailed illustration is given for corrosion, stress, weld, heat treat, and mechanical damage assessment.

Method and apparatus for measurement of material condition

Disclosed are method and apparatus for measuring material properties. Segmented field sensors have multiple sensing elements at different spatial geometries to capture field components having substantially different depths of penetration. These sensors are excited and measured on these different sensing elements to facilitate characterization of unknown material properties. This is illustrated in some embodiments using eddy current sensors to characterize materials that are frequency dispersive and/or do not produce a measurable phase shifts. Only a single scalar quantity may provide independent information from one or more of the sensing elements. Property estimation techniques, such as those using precomputed databases of sensor responses are used to estimate the unknown material properties.

Segmented field eddy current sensing for dispersive property measurement and complex structures

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.

Method and apparatus for non-destructive evaluation of materials

A substantially planar eddy-current sensor having durability enhancing pillars in an active region is provided. The pillars are distributed and sized so as to have limited effect on the sensor's performance. When the sensor is mounted on a component such that the sensor experiences forces on a top and bottom surface, the pillars bear the load reducing the load bore by the active elements (e.g., drive winding, sense elements). A sensor with redundant drive windings and/or redundant sense elements is disclosed. The redundant elements may be connected to separate electronics. Another aspect relates to providing a reference transformer for calibration of a sensor. The secondary windings of the reference transformer are connected in series with the sense elements of the sensor to be calibrated. Transimpedance measurements are made when the drive winding of the reference transformer is excited. The measurements are used to correct transimpedance measurements made when the drive winding of the sensor is excited. A system having an impedance analyzer and a plurality of multiplexing units is disclosed for monitoring a plurality of sensor. Each multiplexing units directs an excitation signal to the drive winding of a respective sensor and returns, serially, the sense element responses back to the impedance analyzer. The system coordinates the excitation of each sensor and return of the sensor response to share a serial network. The multiplexing units may have a reference transformer for calibration of their respective sensors. Optical communication may be used.

Durability enhanced and redundant embedded sensors

The condition of internal or hidden material layers or interfaces is monitored and used for control of a process that changes a condition of a material system. The material system has multiple component materials, such as layers or embedded constituents, or can be represented with multiple layers to model spatial distributions in the material properties. The material condition changes as a result of a process performed on the material, such as by cold working, or from functional operation. Sensors placed proximate to the test material surface or embedded between material layers are used to monitor a material property using magnetic, electric, or thermal interrogation fields. The sensor responses are converted into states of the material condition, such as temperature or residual stress, typically with a precomputed database of sensor responses. The sensor responses can also be used to determine properties of the test material, such as electrical conductivity or magnetic permeability, prior to conversion to the material state. The states are used to support control decisions that control the process or operation causing the material condition to change.

Internal material condition monitoring for control

A framework for adaptively managing the life of components. A sensor provides non-destructive test data obtained from inspecting a component. The inspection data may be filtered using reference signatures and by subtracting a baseline. The filtered inspection data and other inspection data for the component is analyzed to locate flaws and estimate the current condition of the component. The current condition may then be used to predict the component's condition at a future time or to predict a future time at which the component's condition will have deteriorated to a certain level. A current condition may be input to a precomputed database to look up the future condition or time. The future condition or time is described by a probability distribution which may be used to assess the risk of component failure. The assessed risk may be used to determine whether the part should continue in service, be replaced or repaired. A hyperlattice database is used with a rapid searching method to estimate at least one material condition and one usage parameter, such as stress level for the component. The hyperlattice is also used to rapidly predict future condition, associated uncertainty and risk of failure.

Component adaptive life management

An apparatus for the nondestructive measurement of materials that includes at least two layers of electrical conductors. Within each layer, a meandering primary winding is used to create a magnetic field for interrogating a test material while sense elements or conducting loops within each meander provide a directional measurement of the test material condition. In successive layers extended portions of the meanders are rotated so that the sense elements provide material condition in different orientations without requiring movement of the test circuit or apparatus. Multidirectional permeability measurements are used to assess the stress or torque on a component. These measurements are combined in a manner that removes temperature effects and hysteresis on the property measurements. This can be accomplished through a correction factor that accounts for the temperature dependence.

Method for stress assessment that removes temperature effects and hysteresis on the material property measurements

Described are methods for monitoring of stresses and other material properties. These methods use measurements of effective electrical properties, such as magnetic permeability and electrical conductivity, to infer the state of the test material, such as the stress, temperature, or overload condition. The sensors, which can be single element sensors or sensor arrays, can be used to periodically inspect selected locations, mounted to the test material, or scanned over the test material to generate two-dimensional images of the material properties. Magnetic field or eddy current based inductive and giant magnetoresistive sensors may be used on magnetizable and/or conducting materials, while capacitive sensors can be used for dielectric materials. Methods are also described for the use of state-sensitive layers to determine the state of materials of interest. These methods allow the weight of articles, such as aircraft, to be determined.

Magnetic field characterization of stresses and properties in materials

An apparatus for the nondestructive measurement of materials that includes at least two layers of electrical conductors. Within each layer, a meandering primary winding is used to create a magnetic field for interrogating a test material while sense elements or conducting loops within each meander provide a directional measurement of the test material condition in different orientations without requiring movement of the test circuit or apparatus. In a bidirectional implementation the meanders are oriented 90&#xb0; apart while in a quadridirectional implementation the meanders are orientated at &#x2212;45, 0, 45, and 90&#xb0;. Multidirectional permeability measurements are used to assess the stress or torque on a component. These measurements are combined in a manner that removes temperature effects and hysteresis on the property measurements. This can be accomplished through a correction factor that accounts for the temperature dependence. After the correction, the permeability measurement is then used to assess the local stresses and strains in the material of interest.

Test circuit with sense elements having associated and unassociated primary windings

Reference standards or articles having prescribed levels of damage are fabricated by monitoring an electrical property of the article material, mechanically loading the article, and removing the load when a change in electrical properties indicates a prescribed level of damage. The electrical property is measured with an electromagnetic sensor, such as a flexible eddy current sensor, attached to a material surface, which may be between layers of the article material. The damage may be in the form of a fatigue crack or a change in the mechanical stress underneath the sensor. The shape of the article material may be adjusted to concentrate the stress so that the damage initiates under the sensor. Examples adjustments to the article shape include the use of dogbone geometries with thin center sections, reinforcement ribs on the edges of the article, and radius cut-outs in the vicinity of the thin section. A test circuit includes sensing elements between concentric circular segments of the primary winding and located every other half wavelength of the primary winding.

Eddy current sensor with concentric segments

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Chula Vista, CA, United States of America

Andrew P Washabaugh