Patent application number | Description | Published |
20080258720 | Hybrid wound/etched winding constructs for scanning and monitoring - 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. | 10-23-2008 |
20090192755 | Material property estimation using inverse interpolation - Magnetic field sensor probes are disclosed which comprise primary or drive windings having a plurality of current carrying segments. The relative magnitude and direction of current in each segment are adjusted so that the resulting interrogating magnetic field follows a desired spatial distribution. By changing the current in each segment, more than one spatial distribution for the magnetic field can be imposed within the same sensor footprint. Example envelopes for the current distributions approximate a sinusoid in Cartesian coordinates or a first-order Bessel function in polar coordinates. One or more sensing elements are used to determine the response of a test material to the magnetic field. These sense elements can be configured into linear or circumferential arrays. | 07-30-2009 |
20090315540 | PRIMARY WINDINGS HAVING MULTIPLE PARALLEL EXTENDED PORTIONS - 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. | 12-24-2009 |
20100026285 | 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. | 02-04-2010 |
20100045277 | Magnetic field characterization of stresses and properties in materials - 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. | 02-25-2010 |
20110163742 | Magnetic Field Characterization of Stresses and Properties in Materials - 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. | 07-07-2011 |
20120013334 | Material Property Estimation Using Inverse Interpolation - Magnetic field sensor probes are disclosed which comprise primary or drive windings having a plurality of current carrying segments. The relative magnitude and direction of current in each segment are adjusted so that the resulting interrogating magnetic field follows a desired spatial distribution. By changing the current in each segment, more than one spatial distribution for the magnetic field can be imposed within the same sensor footprint. Example envelopes for the current distributions approximate a sinusoid in Cartesian coordinates or a first-order Bessel function in polar coordinates. One or more sensing elements are used to determine the response of a test material to the magnetic field. These sense elements can be configured into linear or circumferential arrays. | 01-19-2012 |
Patent application number | Description | Published |
20090001974 | Torque and load monitoring using magnetic sensor arrays - 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. In a bidirectional implementation the angle is 90° while in a quadridirectional implementation the relative angles are −45, 0, 45, and 90°. 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 corrections, the permeability measurement is then used to assess the local stresses and strains in the material of interest. | 01-01-2009 |
20110210724 | Durability Enhanced and Redundant Embedded Sensors - 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. | 09-01-2011 |
20120271824 | Performance Curve Generation For Non-Destructive Testing Sensors - Methods and apparatus for enhancing performance curve generation, damage monitoring, and improving non-destructive testing performance. Damage standards used for performance curve generation are monitored using a non-destructive testing (NDT) sensor during a damage evolution test performed with the standard. The evolution test may be intermittently paused to permit ground truth data to be collected in addition to the NDT sensor data. A damage evolution model may be used to estimate ground truth data during the intervening periods of the damage evolution test. The NDT sensor data and ground truth data are used to generate performance curves for the NDT system. Multiple sensors may be monitored at multiple locations on the damage standard and multiple damage evolution tests may be performed with multiple damage standards. | 10-25-2012 |
20130269450 | Method And Apparatus For Load And Additional Property Measurement - A system and method for measuring load and an additional property using a sensor gasket embedded between two components. The sensor gasket may include a sensor layer and a conductive layer. A gap between the sensor layer and conductive layer may be filled with a load sensitive material. The thickness of the load sensitive material varies with the load applied to the two components between which the sensor gasket sits. The sensor operates in a first mode to obtain a sensor measurement that depends on the distance between the sensor layer and conductive layer. The sensor measurement then used to estimate the applied load. The sensor operates in a second mode to estimate a property of one or both of the components. The property of interest may be cracking, material loss due to corrosion, temperature, or another property of the component. | 10-17-2013 |