Ultrasonic examination method of structures with rounded surfaces focused with a multicentric radius

Abstract

The present invention relates to a method of ultrasonic examination of a structure having a radiused surface focused with a multi-center radius for examination of a radiused surface (26) having a radiused portion (10, 22) of varying radius without mechanically adjusting an array transducer (30, 46). A plurality of focusing laws are designed to electronically steer and focus ultrasound at respective focal points corresponding to the center of curvature of a simulated radiused surface having a varying radius. A mechanical probe (40) carrying the array transducer is positioned to two physical locations outside the radius region and having a spatial relationship that varies less than the radius of the radiused surface variation. As the probe is moved along the radiused portion, the probe maintains the array transducer in a constant position relative to the radiused portion. As the array transducer scans the radiused portion, the array transducer is electronically adjusted to sequentially focus at the respective focal points.

Description

Technical Field

[0001] This disclosure generally relates to methods and apparatus for ultrasound examination, and in particular, to methods and apparatus for ultrasound examination of composite structures having rounded corner surfaces. Background Technology

[0002] The need to maximize the performance and minimize the weight of commercial aircraft has led to the widespread use of composite materials, such as fiber-reinforced plastics. Various elongated composite structures can have relatively narrow internal cavities that require inspection to ensure the structure meets production and / or performance specifications. In many cases, these internal cavities are partially defined by reinforcements, each consisting of a web and a flange that meet at an intersection with one or more fillets. More typically, components made of fiber-reinforced plastics can have either internal or external fillets.

[0003] In mechanical engineering, a fillet is a rounded corner of an interior or exterior angle in a component design. The geometry of a fillet is a concave function line when it is an interior corner and a convex function line when it is an exterior corner. In the manufacture of composite components, fillets are often referred to as “radii” because they typically have an arcuate profile. To avoid potential confusion due to the use of terms such as “radius of a radius,” this disclosure adopts the convention of referring to a fillet with a circular profile as a “fillet surface” and the radial dimension of the fillet surface as a “radius.” As used herein, the term “arc” is a portion of the circumference of a circle. The arc referred to herein is a theoretical (e.g., simulated) construction that can be mathematically defined in a frame of reference for the fillet portion. For example, an arc can be mathematically defined such that a non-parallel first and second flat surface of the fillet portion, mathematically defined in a frame of reference for the fillet portion, is theoretically tangent to the arc at opposite ends.

[0004] In the case of slender composite structures, the use of soft tools creates rounded surfaces whose radii vary along the length of the composite component. There are also numerous individual composite components, each with rounded surfaces of unique radii. Whether inspecting multiple components with different radii or a single component with multiple radii, operators spend considerable time adjusting their probes to different radii. Furthermore, designers of nondestructive inspection (NDI) systems must design and manufacture unique probes comprising arrays of transducer elements (hereinafter referred to as "array sensors") for various profiles of the rounded surfaces.

[0005] Existing methods for ultrasonic inspection of chamfers on composite structures include: (1) physical adjustment of ultrasonic array sensors by an operator while the probe is moving along the fillet surface; (2) highly complex mechanical designs for moving the array sensors during inspection, which may include motor mechanical adjustments, robot articulations, dimensional feedback sensors, etc. (Disadvantages include expensive inspection probes, costly maintenance, and costly robot retraining due to system variability); (3) multiple scans of the fillet surface, each scan obtaining data with different adjustments to the setup file and / or adjustments to the array sensors (this increases cycle time); (4) a single scan using different array sensors placed in different locations (this increases system cost). (and check probe complexity); (5) use beam steering to direct the ultrasonic beam to the rounded surface (this works to some extent, but the data may not be ideal because the physical angle of the ultrasonic waves entering the part is not ideally perpendicular to the part surface in all locations); (6) use the ultrasonic beam steering method to send the sound to the rounded surface of the part at different angles, adjust the electronic beam steering based on the response, and then send the sound to the surface of the part again with the adjusted newer electronic beam, repeating this iterative process several times until a suitable signal response is obtained (this process may tend to mask surface irregularities that the operator would want to see; another drawback is that the software algorithm can be confused by unwanted irregular reflections located near the rounded corners).

[0006] The challenge is to provide a method for inspecting the rounded surfaces of composite components without having to mechanically adjust array sensors, even as the radius changes. Examples would be wing skin reinforcements, fuselage reinforcements, or wing spars, where mechanically adjusting array sensors during inspection becomes very expensive, time-consuming, or results in complex mechanical systems. Summary of the Invention

[0007] The subject matter disclosed below relates to a method and apparatus for ultrasonically inspecting composite components with rounded corner surfaces using a phased-array ultrasonic transducer (hereinafter referred to as "array sensor"). The method is designed with multiple focal points corresponding to the centers of curvature of a simulated curved profile (e.g., an arc) of varying radius of the simulated rounded corner surface. Unlike conventional methods for inspecting structures or portions of rounded corner surfaces with varying radii (hereinafter referred to as "circular portions"), the method proposed herein does not require mechanical probe adjustment. Instead, the method employs electronic adjustment of the focus of ultrasonic waves (hereinafter referred to as "ultrasonic waves") based on the dimensional design (simulated) of the rounded corner portion. Because a scan is developed to focus the ultrasonic waves at different focal points (referencing different radii of the simulated rounded corner surface), this scan is referred to herein as "multi-center radius focusing".

[0008] According to the embodiments disclosed below, multi-center radius focusing can be used to inspect rounded portions with varying radii without requiring mechanical probe adjustment. Multiple focusing laws are designed to electronically redirect and focus the ultrasonic waves at their respective focal points corresponding to the centers of curvature of the simulated rounded surface with varying radii. A mechanical probe carrying an array sensor is positioned at two physical locations outside the rounded region and with a spatial relationship that is less variable than the radius variation of the rounded surface. As the probe moves along the rounded portion, it maintains the array sensor in a constant position relative to the rounded portion. As the array sensor scans the rounded portion, it is electronically adjusted to sequentially focus at its respective focal points.

[0009] The center position of the arc representing the contour of the fillet surface changes with the radius dimension along the length of the fillet surface, but the position of the array sensor relative to the web and flange does not need to change. Because fillet surfaces with different radii also have different centers of curvature, a corresponding focusing law is created for each of a plurality of specified radii. Each focusing law is created to electronically steer and focus the ultrasonic beam at the corresponding focal point. Multiple focal points are selected to cover the expected radius range in the manufactured variable-radius fillet portions. The multi-center radius focusing inspection technique disclosed herein can also accommodate the overlap of different focusing laws, such that defects seen in the sensor data when applying one focusing law will also be seen in the sensor data when applying the next focusing law.

[0010] Multi-center radius focusing can be applied to both inner and outer rounded corner surfaces. While this disclosure focuses on curved array sensors for optimal performance, the method can also be applied using linear (flat) array sensors.

[0011] Although various embodiments of methods and apparatus for ultrasound examination using composite components with multi-center radius focusing are described in detail later herein, one or more of those embodiments may be characterized by one or more of the following aspects.

[0012] One aspect of the subject matter disclosed in detail herein is a method for inspecting a rounded portion having a non-parallel first flat surface and a second flat surface connected by rounded corner surfaces, the method comprising: (a) placing a probe body in a position relative to the rounded portion such that the scanning plane of an array sensor of transducer elements supported by the probe body intersects and is perpendicular to the longitudinal axis of the rounded corner surface; (b) pulsating corresponding apertures of the transducer elements of the array sensor to transmit a first plurality of beams focused at a first focal point and steered in the scanning plane at a corresponding steer angle, wherein the first plurality of beams impinge on corresponding regions of the rounded corner surface; (c) after each of the first plurality of beams has been transmitted, processing transducer output signals from the transducer elements of each aperture to derive corresponding parameter values ​​characterizing the corresponding echoes returning from the rounded portion after each of the first plurality of beams impinges on the rounded corner surface. (d) Pulsating the corresponding apertures of the transducer elements of the array sensor to transmit a second plurality of beams focused at a second focal point and steered in the scanning plane at a corresponding steer angle, the second plurality of beams striking a corresponding region on the rounded surface; and (e) after each of the second plurality of beams has been transmitted, processing the transducer output signal from the transducer element of each aperture to derive a corresponding parameter value characterizing the intensity of the corresponding echo returning from the rounded portion after each of the second plurality of beams strikes the rounded surface, wherein the first focal point is juxtaposed at the first curvature center of a first arc having a first radius, the second focal point is juxtaposed at the second curvature center of a second arc having a second radius different from the first radius, and the first and second arcs are calculated in the reference frame of the rounded portion such that the first and second flat surfaces of the rounded portion are tangent to each of the first and second arcs.

[0013] Another aspect of the subject matter disclosed in detail below is an apparatus for inspecting rounded corner portions, the apparatus comprising: an array sensor of transducer elements; a probe body holding the array sensor of transducer elements; and a pulse generator / receiver device programmed to perform operations including: (a) pulsating the transducer elements of the array sensor according to a first transmission focusing law, the first transmission focusing law being calculated such that the array sensor emits a first beam focused at a first focal point located along the centerline of the array sensor; (b) after the first beam is emitted, processing the transducer output signal from the transducer elements according to a first receiving focusing law, the first receiving focusing law being calculated such that the array sensor derives a first parameter value, the first parameter value being characterized by the roundness of the impacted rounded corner portion. (c) Pulsating the transducer elements of the array sensor according to the second transmission focusing law, which is calculated such that the array sensor emits a second beam focused at a second focal point located along the centerline of the array sensor; and (d) after the second beam is emitted, processing the transducer output signal from the transducer elements according to the second receiving focusing law, which is calculated such that the array sensor derives a second parameter value characterizing the intensity of the echo received after the second beam impacts the rounded corner surface, wherein the first focal point is located at a first distance from the center of the array sensor, and the second focal point is located at a second distance from the center of the array sensor, the second distance being different from the first distance.

[0014] On the other hand, there is a method for inspecting rounded portions, the method comprising: (a) generating a cross-sectional model of a probe including a first surface and a second surface connected by rounded corner surfaces, the probe including an array sensor of transducer elements, the cross-sectional model including a first line and a second line representing the respective contours of the first surface and the second surface, and a plurality of arcs spanning a expected range of variation of the radius of the rounded corner surfaces of the rounded portion, each of the arcs terminating at the first line and the second line; (b) calculating a set of transmission focusing laws, which, when executed, will cause the array sensor to emit multiple beams focused at multiple focal points located at different distances from the center of the array sensor, wherein the multiple focal points correspond to different distances from the center of the analog array sensor of the transducer elements. (c) Calculate a set of receiving focusing laws designed such that the array sensor derives multiple parameter values ​​characterizing the intensity of the echo received after multiple beams strike the rounded surface of the rounded portion; (d) Place the probe in a position relative to the rounded portion that conforms to the relative position represented by the cross-sectional model; (e) Pulse the corresponding apertures of the transducer elements of the array sensor to transmit multiple beams focused at multiple focal points according to a set of transmission focusing laws; and (f) After each of the multiple beams is transmitted, process the transducer output signal from the transducer elements according to a set of receiving focusing laws to derive a set of parameter values ​​characterizing the intensity of the echo received after multiple beams strike the rounded surface of the rounded portion.

[0015] Other aspects of methods and equipment for ultrasound examination of composite components using multi-center radius focusing are disclosed below. Attached Figure Description

[0016] The features, functions, and advantages discussed in the preceding sections can be implemented independently in various embodiments or combined in other embodiments. To illustrate the above and other aspects, various embodiments will be described below with reference to the accompanying drawings. All figures not briefly described in this section are not drawn to scale.

[0017] Figure 1 This is an illustration showing an exploded end view of a typical composite skin and I-beam assembly.

[0018] Figure 2 This is an illustration showing an isometric view of a portion of an L-shaped longitudinal beam with a circular radius. The arrows indicate the direction of travel of the scanner during the radius inspection, which will be referred to herein as the X-direction.

[0019] Figure 3 It is a diagram representing an inspection probe and a component with the radius to be inspected, in CAD model format.

[0020] Figure 4 This is a diagram showing the position of a bending array sensor of an ultrasonic transducer element concentric with the rounded surface of the composite component being inspected.

[0021] Figure 5 This is a diagram showing the position of a bending array sensor of an ultrasonic transducer element that is not concentric with the rounded surface of the composite component being inspected according to the multi-center radius focusing technique proposed herein.

[0022] Figure 6 This is a diagram illustrating the trigonometric relationship used to derive the transducer element offset for calculating the time delay to be incorporated into the focusing law associated with the curved array sensor.

[0023] Figure 7 This is a diagram illustrating the relationship used to derive the transducer element offset for calculating the time delay to be incorporated into the focusing law associated with a linear array sensor.

[0024] Figure 8 This is a flowchart identifying the steps of a process for designing and implementing a system for multi-center radius focusing inspection of rounded corner portions, according to one embodiment.

[0025] Figure 9 This is a side view illustration of a mechanical probe designed to support a curved array sensor in a constant position during longitudinal scanning at the rounded corners.

[0026] Figure 10-15 This is an illustration showing an example of limitations in inspection coverage for various array sensor / rounded surface configurations. Figure 10-14 In the middle, the array sensor is curved; in Figure 15 In this configuration, the array sensor is linear. Figure 10-12 In the middle, the rounded corner surface is concave; in Figure 13-15 In the middle, the rounded corner surface is raised.

[0027] Figure 16 This is a block diagram illustrating a control system according to one embodiment.

[0028] Figure 17 is an illustration of scan data displayed in a suitable position on a display according to one embodiment.

[0029] Referring below to the accompanying drawings, similar elements in different drawings have the same reference numerals. Detailed Implementation

[0030] For illustrative purposes, methods and apparatus for ultrasound examination using composite components with multi-center radius focusing will now be described in detail. However, not all features of actual implementations are described in this specification. Those skilled in the art will understand that in the development of any such embodiment, many implementation-specific decisions must be made to achieve the developer's specific objectives, such as complying with system-related constraints and business-related constraints, which will vary across implementations. Furthermore, it will be understood that such development efforts can be complex and time-consuming, but will be routine work for those of ordinary skill in the art who will benefit from this disclosure.

[0031] For ultrasonic inspection of composite structures, the ultrasonic beam should ideally be incident at a 90-degree angle to the local surface of the composite component being inspected. If the beam is not incident at a 90-degree angle, it will deviate from the normal and refract, and echoes from any possible internal structures or anomalies will be suboptimal. Traditionally, a 90-degree incident angle is maintained by holding an array of sensors in a precisely fixed position in space relative to the surface.

[0032] A process for non-destructive inspection of fillet portions with varying radii will now be described. For example, this process can be applied to the inspection of slender composite components such as wing panel longitudinals made of fiber-reinforced plastic. The radius of the fillet surface at the fillet joint area (intersection) of such slender composite components can be constant or vary along the length of the component.

[0033] Instead of mechanically adjusting the probe, multiple wavefronts are created by a computer-controlled array of sensors to accommodate the varying radii and shapes of the rounded corner portions. These multiple wavefronts are adjusted using ultrasonic beamforming application software. Phase control of the elements in the multiple array sensors electronically enables the transmission of multiple sets of ultrasonic beams to examine the different radii and shapes, covering the intended (i.e., predicted) surface of the component and the entire range of diameter variations. Phase control is performed according to a predetermined focusing law. (As used herein, the term "focusing law" refers to a programmed pattern of time delays applied to the pulses and outputs of the individual transducer elements during the transmission and reception of the beamforming.)

[0034] Figure 1This is a partial sectional view of an exploded composite skin and beam assembly. The composite skin and beam assembly includes an elongated beam 10 having a web 14 positioned between a first flange 16 and an opposing second flange 18. The web 14 may have a height designed to provide the required resistance to applied loads. The first flange 16 and the second flange 18 may be generally planar members. The web 14, the first flange 16, and the second flange 18 may be constant along the span of the beam (i.e., into the page), or they may vary continuously or discontinuously along the span of the beam 10. The web 14, the first flange 16, and the second flange 18 are formed of a fiber-reinforced plastic material having multiple layers. The assembly also includes a skin 20 attached to the second flange 18 using, for example, a suitable adhesive material. The skin 20 is also made of a fiber-reinforced plastic material.

[0035] Before attaching the longitudinal beam 10 to the skin 20, the longitudinal beam 10 is typically inspected for defects. In particular, a scanner platform traveling along the length of the longitudinal beam 10 can be used to perform non-destructive inspection of each rounded corner region 12a / 12b. According to the embodiments disclosed herein, the scanner platform carries an ultrasonic probe that transmits a focused ultrasonic beam and generates a corresponding return signal for each echo returning to the probe.

[0036] exist Figure 1 In the example shown, the longitudinal beam 10 has an I-shaped cross-sectional profile. The NDI system disclosed herein also has applications in inspecting the fillets of composite components with alternative geometries. For example, Figure 2 A portion of the L-shaped composite component 22 to be inspected is shown. The composite component 22 includes a web 24, a flange 28 (forming an obtuse angle with the web 24), and a fillet 25. Using the inspection techniques disclosed herein, the fillet 25 can be scanned in a series of parallel planes perpendicular to the X-axis and spaced equally apart. This is achieved by arraying sensors (…) after each plane has been scanned. Figure 2 (Not shown in the image) The scanner completes the task by moving a predetermined incremental distance. The scanner will move in the X direction (by...) Figure 2 (The arrow in the image indicates that the arrow travels along the length of the rounded corner by 25 degrees.)

[0037] According to the embodiments described below, multi-center radius focusing inspection is used to inspect fillet portions with variable radius dimensions without mechanically adjusting the array sensor. The focusing laws are designed to electronically redirect and focus ultrasonic waves at a focal point, which is calculated to be the center of an arc representing the contour of a fillet surface with a specified radius dimension. To inspect fillet surfaces with varying radius dimensions, additional focusing laws corresponding to other specified radius dimensions are created. A file containing digital data representing the focusing laws is written and stored in a non-transitory tangible computer-readable storage medium included in the phased array instrument. In the focusing law file, time delays for the transmission and reception of ultrasonic waves are present. These time delays control the electronic emission of the ultrasonic transducers of the array sensor during transmission and the multiplexing of the ultrasonic transducer outputs during reception. The multi-center radius focusing inspection technique can also accommodate the overlap of different focusing laws, so, for example, a drawback seen in sensor data acquired when a focusing law for one radius is applied will also be seen in sensor data acquired when a focusing law for another radius is applied.

[0038] According to the inspection method disclosed herein, the scanning system is programmed to transmit corresponding multiplicity ultrasonic beams in each scanning plane, each multiplicity ultrasonic beam being focused at a corresponding focal point located between the array sensor and the rounded corner surface. A cross-sectional CAD model of the probe body 40 is first generated at a predetermined position relative to a component. Figure 3 As shown in the diagram), to determine the scanning procedure, the component is designed to include a web 24 and a flange 28 connected by a rounded joint area (hereinafter referred to as "rounded corners"), which are formed by... Figure 3 (The corresponding straight line in the model represents this). The rounded corner is designed to have an arcuate surface, the cross-sectional shape of which is an arc. The CAD model further includes curved lines representing the curved array sensor 30 (hereinafter referred to as "array sensor 30") and lines representing multiple bearings including rollers 42a and 42b rotatably mounted on respective axes 44. The array sensor 30 is located in the probe body 40, and the probe body 40 is positioned relative to the rounded corner component, taking into account factors such as... Figure 3 As seen, the rollers 42 of the corresponding group will contact the web 24 and flange 28. The positions of the array sensors 30 relative to the web 24 and flange 28 are determined from the CAD model based on the known geometry and dimensions of the probes and components. The relative positions of the individual transducers are included in these values ​​determined from the CAD model. In other embodiments, the array sensors are straight, and / or the probes have sliding contacts instead of bearings; this configuration will be incorporated into the CAD model.

[0039] exist Figure 3In the cross-sectional CAD model shown, the fillet surface of the part to be inspected is represented by a series of arcs 34, which span the expected total variation of the radius of the fillet surface. For illustrative purposes, an embodiment in which the arcs 34 are non-concentric circular segments with different radii will be described. The arcs 34 intersect the web 24 and the flange 28. Ideally, the web 24 and the flange 28 have flat surfaces represented by straight lines in the cross-sectional CAD model. The arcs 34 are drawn in the CAD model such that the straight lines representing the surfaces of the web 24 and the flange 28 will be tangent to each of the arcs 34 at the respective endpoints of the arcs. If the fillet radius of the part is non-circular, the actual surface shape is projected into the CAD model. In one embodiment of the method, a series of non-circular shapes are projected from a physical cross-sectional photomicrograph of the part to be inspected.

[0040] The method for inspecting the rounded components proposed herein uses multi-center radius focusing. This inspection method is characterized by the following steps. First, a cross-sectional CAD model of a probe is generated that contacts the rounded component, which includes a first flat surface and a second flat surface connected by rounded surfaces. The probe comprises an array sensor of transducer elements. The cross-sectional CAD model includes a first line and a second line representing the respective contours of the first and second flat surfaces, and multiple arcs spanning a desired range of variation in the radius of the rounded surface of the rounded component, each of these arcs terminating at the first and second lines. A set of transmission focusing laws is calculated, which, when executed, will cause the array sensor to emit multiple beams focused at multiple focal points located at different distances from the center of the array sensor. The multiple focal points correspond to the respective centers of the multiple arcs located at different distances from the center of the simulated array sensor of the transducer elements. Additionally, a set of receiving focusing laws is calculated, which is designed such that the array sensor derives multiple parameter values ​​characterizing the intensity of the echoes received after impacting the multiple beams on the rounded surface of the rounded component. The transmission focusing law and the reception focusing law are stored in a non-transitory tangible computer-readable storage medium contained in the phased array instrument, and are then retrieved as needed during the inspection process.

[0041] During the inspection process, the probe body 40 will be positioned relative to the rounded corner component, such that its position in the cross-sectional plane conforms to the [missing information - likely a component name or component]. Figure 3 The cross-sectional model shown represents the relative positions. As the probe body 40 moves along the length of the rounded corner component, the array sensor 30 is electronically adjusted to account for changes in the radius dimension.

[0042] In traditional radius inspection, a curved array of sensors is aligned concentrically with a rounded surface. Figure 4This is a diagram showing the position of a curved array sensor 30 concentric with the rounded surface 26 of the rounded corner of the composite component being inspected. The array sensor 30 includes multiple transducer elements 32 arranged side by side along an arc. In the example shown, the array sensor 30 includes sixty-four transducer elements numbered E1 to E64 respectively. In this case, the ultrasonic beam travels the same number of times to all the individual points of concentricity 8 because the transducer elements E1-E64 are all equidistant from the surface of the array sensor 30.

[0043] Conversely, according to the multi-center radius focusing technique proposed in this paper, the curved array sensor does not need to be concentrically aligned with the rounded surface. The corresponding apertures of the transducer elements of the array sensor 30 are pulsed to transmit multiple beams, each focused at a multiple focal point, according to a set of transmission focusing laws. After each of the multiple beams is transmitted, the transducer output signal from the transducer elements is processed according to a set of receiving focusing laws to derive a set of parameter values ​​characterizing the intensity of the echoes received after the multiple beams impact the rounded surface of the rounded component.

[0044] Figure 5 This is an illustration showing the position of the curved array sensor 30, which is not concentric with the rounded surface being inspected. Figure 5 In the example shown, array sensor 30 includes sixty-four transducer elements, numbered E1 to E64 respectively. However, it should be understood that the non-destructive inspection techniques disclosed herein do not require the array sensor to have sixty-four transducer elements. Array sensor 30 may have more or fewer transducer elements. To form a focused ultrasonic beam 36, only a subset of transducer elements E1-E64 is pulsed. For example, a group of adjacent transducer elements E31-E42 may be sequentially activated according to transmission focusing laws designed to produce a focused ultrasonic beam 36 with a specified focal length FL and a steering angle A. This grouping of sequentially activated transducer elements will be referred to herein as an “aperture.” As is known to those skilled in the art, for each transmitted beam, the same aperture (e.g., aperture 31 of array sensor 30) is used to detect the echo response and convert that echo response into corresponding multiple transducer output signals.

[0045] As is well known in the art, a set of focusing laws (hereinafter referred to as "transmission focusing laws") applies when the elements of the aperture are transmitting a beam, and another set of focusing laws (hereinafter referred to as "receive focusing laws") applies when the same elements convert the echo response to form a received beam. The focusing laws used for transmission and those used for reception are different, but related because the receive focusing laws are designed such that for each transmitted ultrasonic beam 36 focused at a particular focal point, the array sensor detects the ultrasonic beam of the corresponding branch returning from the rounded part via the same focal point. For example, the time delay applied to elements E31-E42 for detecting the received beam from the focal point will be the same as the time delay used for the beam transmitted from elements E31-E42 to the same focal point, but the order in which the electrical echo data is acquired from elements E31-E42 will be the reverse of the order in which those elements are pulsed.

[0046] Figure 5 The positions of the curved array sensor 30 that are not concentric with either the rounded surface 26a (indicated by a continuous line) having a radius of 0.250 inches or the rounded surface 26b (indicated by a dashed line) having a radius of 0.125 inches are shown. In the first transmission beamforming sequence (in... Figure 5 During the second transmission beamforming sequence (as shown), the transducer elements are pulsed to transmit multiple ultrasonic beams 36 focused at a focal point FP1 according to a first set of transmission focusing laws (at different numbers). The focal point FP1 is positioned along the centerline CL of the array sensor 30 at a first distance from the array center. Figure 5 During the period (not shown), the transducer elements are pulsed to transmit multiple ultrasonic beams focused at focal point FP2 according to a second set of transmission focusing laws (at different numbers). Focal point FP2 is located at a second distance from the center of the array sensor 30 along the centerline CL, which is greater than the first distance.

[0047] The corresponding echo returns from the rounded corner component to the same transducer element that is pulsating. The detected transducer element converts the received ultrasonic energy into an electrical transducer output signal. Using known gating techniques, and according to a set of receiver focusing laws, the ultrasonic pulse generator / receiver device (…)… Figure 5 (Not shown in the image) These transducer output signals are time-delayed. The gated signal is then gain-corrected to compensate for varying amounts of energy loss caused by low transmission efficiency at larger angles, and the gain-corrected signal is then summed by the ultrasonic pulse generator / receiver device to form a return signal representing a parameter value characterizing the intensity of the echo received from the rounded corner component.

[0048] according to Figure 5 One proposed implementation of the multi-center radius focusing technique shown in the previously described CAD model ( Figure 3(As shown) Five non-concentric arcs 34 are used. The corresponding radii of adjacent arcs 34 differ by an incremental radius equal to 0.025 inches (ΔR = 0.025 inches), resulting in a series of arcs 34 with the following radii: 0.125 inches, 0.150 inches, 0.180 inches, 0.220 inches, and 0.250 inches. Therefore, this set of transmission focusing laws comprises five transmission focusing laws designed to focus the corresponding ultrasonic beams 36 at the corresponding focal points juxtaposed at the center of the arcs 34. According to this proposed embodiment, the five focusing laws are used to inspect composite rounded components having rounded surfaces varying from 0.125 inches to 0.250 inches, and each focusing law handles a radius variation of approximately 0.03 inches. For example, the center position for a rounded surface with a radius equal to 0.150 inches is 0.025 inches closer to the array sensor surface than the center position for a rounded surface with a radius equal to 0.125 inches. Furthermore, the multi-center radius focusing inspection technique proposed in this paper can adapt to the overlap of different focusing laws, such that anomalies seen in sensor data obtained when the focusing law for a 0.125-inch radius is applied during interrogation will also be seen in sensor data obtained when the focusing law for a 0.150-inch radius is applied.

[0049] In order to focus the beam at a focal point that is not juxtaposed with the center of the curved array sensor 30 without moving the array sensor 30, the individual ultrasonic waves emitted by the respective transducer elements must travel different distances from the array sensor surface to reach the focal point. This is accomplished by applying a time delay to the individual elements of the array sensor 30, so that the ultrasonic waves meet simultaneously at the focal point. Figure 5 This is illustrated by showing an external element of the array sensor 30 that is further away from the focal point FP1 (0.376 inches) than the distance (0.338 inches) separating the center of the array sensor 30 from the focal point FP1. Therefore, the time delay between the external element and the central element of the array sensor 30 will be (0.376 - 0.338) = 0.038 inches divided by the ultrasonic speed (in inches per second).

[0050] For each aperture in a multi-center radius focusing scheme, including each focal point, to be applied to a specific rounded corner component, the time delay is calculated. The time delay during activation of the first and second transducer elements can be calculated by first determining the difference between the corresponding distances separating the first and second transducer elements from the focal point and then dividing that difference by the ultrasonic velocity. The distance of each element from the focal point can be determined relative to, for example... Figure 6The corresponding offset of the center of the array sensor surface shown is determined, illustrating a curved array sensor 30 having a curvature center 60 and an array center 38 having an equal number of transducer elements 32 on both sides. The coordinates of the array center 38 are (xpos, ypos). Each transducer element 32 has a transducer element center 62. The transducer element centers of adjacent transducer elements 32 are separated by a distance referred to herein as "pitch". The distance from the curvature center 60 to each transducer element center 62 is the radius of the array sensor 30.

[0051] Reference Figure 6 The time delay calculation follows the trigonometric identity of angle θ (theta), which can be expressed by the following equation:

[0052] arclen = ((i - 0.5) * pitch) - ArrayARC / 2

[0053] theta = arclen / radius

[0054] elx(i) = xpos + radius * sin(theta)

[0055] ely(i)=ypos+radius*(1-cos(theta))

[0056] Where "i" is the number of transducer elements; elx(i) and ely(i) are the coordinates of the transducer element center 62 of the i-th transducer element; "theta" is the central angle between the radial line from the curvature center 60 to the transducer element center 62 of the i-th transducer element and the radial line from the curvature center 60 to the array center 38; "arclen" is the arc length of the arc relative to the central angle "theta" (measured in radians) and extending from the transducer element center 62 of the i-th transducer element to the array center 38; and "ArrayARC / 2" is equal to half the arc length of the array sensor 30. Figure 6 In the specific example shown, the angle theta is the angle between the radial line from the center of curvature 60 to the array center 38 and the radial line from the center of curvature 60 to the center of transducer element 62 of the third transducer element number E3 (i=3). Therefore, the x and y offsets for the i-th transducer element are functions of theta, i.e.:

[0057] xoffset = radius * sin(theta)

[0058] yoffset = radius * (1 - cos(theta))

[0059] The following equation can be used to calculate the linear array sensor 46 ( Figure 7 The offset of the time delay shown in the figure:

[0060] elx(i) = xpos - ArrayARC / 2 + ((i - 0.5) * pitch)

[0061] ely(i)=ypos

[0062] Where "i" is the number of transducer elements; (xpos, ypos) are the coordinates of the array center 38; elx(i) and ely(i) are the offset coordinates of the transducer element center 62 of the i-th transducer element; "pitch" is the distance between the transducer element centers 62 of adjacent transducer elements 32; and "ArrayARC / 2" is equal to half the length of the linear array sensor 46. For planar array applications, yoffset becomes zero.

[0063] Figure 8 This is a flowchart illustrating the steps of a process 100 for designing and implementing a system for multi-center radius focusing inspection of fillet components. The first stage of this process is positioning a bending array sensor within the probe body (step 102). A cross-sectional CAD model of the probe in contact with the component to be inspected is then generated. The component may include a non-parallel first and second surface (e.g., a flat surface) connected by fillet surfaces. The cross-sectional model includes a first line and a second line representing the respective contours of the first and second surfaces. Because the true radius of the fillet surface of the component to be inspected is not known, the expected radius in the CAD model is represented by a series(s) of arcs(s) with different radii, spanning the expected total range of radius variation (step 104). Each of these arcs terminates at the first and second lines.

[0064] Using a CAD model, an ultrasonic beam focused at the center of the arc is graphically created (step 106). Using the defined beam, sets of transmission focusing laws and reception focusing laws are calculated (step 108). More precisely, a set of transmission focusing laws is calculated to control the transducer element to emit multiple beams focused at multiple focal points juxtaposed with the centers of the multiple arcs. Additionally, a set of reception focusing laws is calculated, designed to receive the corresponding return signals representing the corresponding echoes returning to the transducer element via the multiple focal points. These focusing laws are then programmed into a pulse generator / receiver device connected to the probe.

[0065] The probe is then positioned adjacent to the inspection area (step 110). More specifically, the probe is placed in a position relative to the rounded corner component, which corresponds to the relative position represented by the cross-sectional CAD model. The scanning plane of the array sensor is preferably perpendicular to the longitudinal axis of the component to be inspected. The probe can move intermittently in incremental increments along its length, starting from the initial position and stopping at the final position.

[0066] Still refer to Figure 8 A non-destructive inspection is performed by pulsating one or more sets of transducer elements of an array sensor to transmit corresponding beams focused at multiple focal points according to the transmission focusing law (step 112). As previously described, different (potentially overlapping) apertures can be used to interrogate corresponding portions of the rounded corner components for each focal point. After each beam is emitted, the resulting echo consists of ultrasonic waves impacting the same transducer elements included in the transmission aperture for each beam. Those transducer elements transmit the impacting ultrasonic waves to the electrical transducer output signal. Those transducer output signals are time-delayed according to the receiving focusing law to form a receiving beam (step 114). Optionally, gain correction is performed on the time-delayed transducer output signals. The transducer output signals are then processed to derive a corresponding set of parameter values ​​for each focal point (step 116). For example, the derived parameter values ​​could be the amplitude of the received beam. Then, optimal parameter values ​​are selected (step 118), and then the optimal parameter values ​​are converted into corresponding pixel values ​​for display (step 120).

[0067] Typically, steps 112, 114, and 116 of process 100 can be performed alternately during the inspection of a rounded component with a protrusion or recess having a non-parallel first flat surface and a second flat surface connected by a rounded corner surface. This basic mode of alternating pulsation and processing is characterized by performing the following steps after the probe body has been placed, such that the scanning planes of the array sensor intersect and are perpendicular to the longitudinal axis of the rounded corner surface: (a) pulsating the corresponding apertures of the transducer elements of the array sensor to transmit a first plurality of beams focused at a first focal point and oriented at a corresponding turning angle in the scanning plane, the first plurality of beams striking the corresponding areas of the rounded corner surface; (b) after each of the first plurality of beams has been emitted, processing the transducer output signal from the transducer element of each aperture to derive a characterization of the first plurality of beams striking the rounded corner surface. (c) Pulsating the corresponding apertures of the transducer elements of the array sensor to transmit a second plurality of beams focused at a second focal point and steered at a corresponding steer angle in the scanning plane, the second plurality of beams striking a corresponding region on the rounded surface; and (d) after each of the second plurality of beams has been transmitted, processing the transducer output signal from the transducer elements of each aperture to derive the corresponding parameter values ​​characterizing the intensity of the corresponding echo returning from the rounded component after each of the second plurality of beams strikes the rounded surface. In this example, the first focal point is juxtaposed at the first curvature center of a first arc having a first radius, the second focal point is juxtaposed at the second curvature center of a second arc having a second radius different from the first radius, and the first and second arcs are calculated in the reference frame of the rounded component such that the first and second flat surfaces of the rounded component are tangent to each of the first and second arcs.

[0068] According to one embodiment, along the length of the rounded corner component (e.g., at...) Figure 2 After the probe (as seen in the X-direction) moves a predetermined distance, multiple sets of ultrasonic beams corresponding to multiple focal points are continuously emitted. The predetermined distance of probe movement is used as the scanning resolution, and this distance is obtained from an encoder attached to the moving platform carrying the probe. According to one embodiment, each scanning plane is perpendicular to the X-axis and separated from adjacent scanning planes by the aforementioned predetermined distance. This spacing determines the horizontal resolution of the pixel image to be displayed. Preferably, the resolution is the same in the vertical direction.

[0069] Figure 9This is a side view illustration of a mechanical probe 50 (hereinafter referred to as "probe 50") designed to support a curved array sensor 30 in a constant position during longitudinal scanning of a rounded component. Probe 50 includes a probe body 40 configured to house the array sensor 30. The array sensor 30 is electrically coupled to a pulse generator / receiver device via a cable 52. Figure 9 (Not shown in the image). The probe body 40 includes a water fitting 54 (indicated by a dashed line) that provides a stream of water that flows between the array sensor 30 and the rounded corner component to acoustically couple the rounded corner surface being inspected.

[0070] The probe body 40 is further configured to abut (contact) two parts (e.g., web 24 and flange 28) of a fillet member with a constant spatial relationship (opposite to the fillet surface of a narrow, filled engagement area with varying radii). The radius of the probe body 40 is designed for the maximum radius of the application (0.25 inches in the figure). At the narrow, filled engagement area of ​​the fillet member, there are two arcs representing fillet surfaces 26a and 26b with corresponding radii of 0.250 inches and 0.125 inches. In reality, these two radius dimensions will not appear at the same location in the structure, but the presence of the two curves is intended to illustrate the concept that the radius dimension decreases below the probe housing. Because the probe body 40 (array sensor housing) is designed for the maximum radius of the application, the radius of the structure can be changed below the corner of the moving probe 50 without mechanically adjusting the probe 50. Multi-center radius focusing allows compensation for the varying radius by adjusting the electronic focus of the ultrasonic beam.

[0071] An array sensor (or a series of array sensors) must be positioned such that the outermost transducer element used in the multi-center radius focusing method provides adequate coverage of the narrow band of the junction area to be inspected (also known as the “corner radius”). This is accomplished by drawing two straight lines from the two tangent points (TP) of the rounded surface (e.g., where the rounded surface meets the web and flange), through the corresponding focal point (FP), and extending back to the face of the array sensor 30. Ensuring sufficient external transducer elements to intercept the straight lines is the goal for achieving array sensor coverage. In practice, given the range of corner radii with their respective centers of curvature (where the focal points are juxtaposed), the farthest center of curvature (foci) from the face of the array sensor 30 is a limiting consideration for array sensor coverage. Data quality is affected by increasing the beam steering angle required to turn the ultrasound across the center of curvature (foci).

[0072] An example proving the principle described in the previous paragraph is in Figures 10 to 15 The diagram shows different array sensor / rounded surface configurations. Figures 10 to 15Each of the diagrams illustrates an array of sensors (or multiple arrays of sensors) spatially related to a pair of rounded surfaces. One rounded surface (26a or 56a) has a radius larger than that of the other rounded surface (26b or 56b). The tangent point TP1 is the flat surface of the rounded component ( Figure 10-15 (not shown in the image) and fillet surface 26a (in the image) Figure 10-12 (in) or 56a (in) Figure 13-15 The point of tangency (in the middle). The focal point FP1 is juxtaposed with the center of curvature of the fillet surface 26a or 56a. The point of tangency TP2 is the flat surface of the fillet component (in the middle). Figure 10-15 (not shown in the image) and fillet surface 26b (in the image) Figure 10-12 (in) or 56b (in) Figure 13-15 The point tangent to each other (in the middle). The focal point FP2 is juxtaposed with the center of curvature of the rounded surface 26b.

[0073] exist Figure 10 In this configuration, the array sensor 30 is curved, and the rounded corner surfaces 26a and 26b are recessed. The outermost portions 2a and 2b of the array sensor 30 (indicated by the thick arc) provide sufficient coverage for inspection of the rounded corner surface 26b.

[0074] exist Figure 11 In this configuration, the array sensor 30 is curved, and the rounded surfaces 26a and 26b are recessed. The outermost portions 4a and 4b of the rounded surface 26b (indicated by the thick arc) are not covered for this array sensor / rounded surface configuration.

[0075] exist Figure 12 In this configuration, the array sensor 30 is curved, and the rounded corner surfaces 26a and 26b are recessed. The outermost portions 2a and 2b of the array sensor 30 (indicated by the thick arc) provide sufficient coverage for the inspection of the outermost portions 6a and 6b (indicated by the thick arc) of the rounded corner blunt surface 26a.

[0076] exist Figure 13 In this configuration, the array sensor 30 is curved, and the rounded corner surfaces 56a and 56b are raised. The outermost portions 2a and 2b of the array sensor 30 (indicated by the thick arc) provide sufficient coverage for inspection of the rounded corner surface 56a.

[0077] exist Figure 14 In this configuration, the array sensor 30 is curved, and the rounded surfaces 56a and 56b are raised. The outermost portions 4a and 4b of the rounded surface 56a (indicated by the thick arc) are not covered for this array sensor / rounded surface configuration.

[0078] exist Figure 15 In the figure, a set of linear array sensors 60a-60c are arranged as shown, and the rounded corner surfaces 56a and 56b are raised. Figure 15 In the arrangement shown, the set of linear array sensors 60a-60c provides sufficient coverage for the rounded corner surfaces 56a and 56b.

[0079] Now refer to Figure 16 An apparatus for inspecting narrow strip-shaped joint areas of elongated composite components is described. The apparatus includes a moving radius scanner platform 70 carrying at least one array sensor 30. According to one embodiment, the control system includes a ground-based computer 84 programmed via motion control application software 86 and NDI scanning application software 88. The control computer 84 is connected to an electronics enclosure (not shown). The electronics enclosure is then connected to the radius scanner platform 70 via a flexible cable (not shown). The electronics enclosure contains the system power supply and integrates all scanner control connections, and provides an interface between the computer and the radius scanner platform 70.

[0080] According to one embodiment, computer 84 may include a general-purpose computer programmed with motion control application software 86, which includes software modules for controlling drive motor 72, causing the radius scanner platform 70 to move in the X direction. The motion control application software 86 also controls motors (not shown) of a cable management system 92. The cable management system 92 consists of two sets of motorized wheels (not shown) that respectively grip the cable connecting the operation control center to the radius scanner platform 70. The motors of the cable management system 92 are computer-controlled, which synchronizes the cable with the movement of the radius scanner platform 70, extending or retracting the cable appropriately. Alternatively, the methods disclosed and claimed herein may be applied using a manual probe without motors.

[0081] like Figure 16 As seen, the ultrasonic pulse generator / receiver device 82 is connected to the array sensor 30 for pulsating the transducer elements of the aperture and processing the transducer output signals from the transducer elements of the same aperture according to a pre-calculated focusing law. The ultrasonic pulse generator / receiver device 82 includes a processor for running a software application that incorporates a corresponding pre-calculated focusing law for each focal point.

[0082] For example, the ultrasonic pulse generator / receiver device 82 is programmed to perform the following operations: First, the transducer elements of the array sensor 30 are pulsed according to a first transmission focusing law, which is calculated such that the array sensor 30 emits a first beam focused at a first focal point located along the centerline of the array sensor 30. After the first beam is emitted, the transducer output signal from the transducer elements is processed according to a first receiving focusing law, which is calculated such that the array sensor 30 derives a first parameter value characterizing the intensity of the echo received after the first beam impacts the rounded surface of the rounded member. Later, the transducer elements of the array sensor 30 are pulsed according to a second transmission focusing law, which is calculated such that the array sensor 30 emits a second beam focused at a second focal point located along the centerline of the array sensor. After the second beam is emitted, the transducer output signal from the transducer elements is processed according to a second receiving focusing law, which is calculated such that the array sensor 30 derives a second parameter value characterizing the intensity of the echo received after the second beam impacts the rounded surface. The first focal point is located at a first distance from the center of the array sensor 30, and the second focal point is located at a second distance from the center of the array sensor 30, the second distance being different from the first distance.

[0083] according to Figure 16 In the illustrated embodiment, an X-axis displacement encoder 74 is mounted to a radius scanner platform 70 (e.g., a rotary encoder attached to an idler wheel). Encoded X-axis position data (in the form of encoder pulses) from the X-axis displacement encoder 74 is received by an ultrasonic pulse generator / receiver device 82, which then sends those encoder pulses to NDI scanning application software 88. The NDI scanning application software 88 uses those pulses to position the scan data at the appropriate location on the display monitor 90, such as... Figures 17A-17E As shown in the image.

[0084] The X-axis motion drive motor 72 may be a programmable stepper motor, which can communicate with the computer 84 via a serial communication interface (not shown). The operator or automated path planning system specifies the path via motion control application software 86 (e.g., in...). Figures 17A-17E The incremental motion required at the multiple radius positions shown in the diagram, and the optional final target position of the radius scanner platform 70. X-axis positioning is controlled using proportional feedback of encoder count data.

[0085] The NDI scanning application software 88 includes software for acquiring and displaying ultrasound data, controlling the ultrasound pulse generator / receiver device 82. The ultrasound pulse generator / receiver device 82 then sends pulses to the array sensor 30 and receives output signals from the array sensor 30. The NDI scanning application software 88 controls, for example... Figures 17A-17EThe scan data shown includes all the details displayed. The pulse generator / receiver device 82 correlates the acquired ultrasound scan data with X-ray position information.

[0086] Ultrasonic examination at frequencies used by the system disclosed herein reveals the presence of acoustic coupling agent between the array sensor and the component being examined. Figure 16 The scanning system shown uses water as the acoustic coupling agent. According to one embodiment, the probe body has a water cavity (not shown) supplied with water via a water supply pipe (not shown), which is also managed by a cable management system 92. The fluid acoustic coupling agent is supplied into the space between the curved array sensor 30 and the rounded corner surfaces of the components. Processing of the returned signals may include applying corresponding gains to the respective returned signals, these gains being selected to compensate for varying amounts of energy loss caused by transmission inefficiencies at higher angles. These corresponding gains may be a function of the distance each echo travels through the fluid acoustic coupling agent. Another variable is the response variation between different elements of the array sensor. Another variable is the number of elements used for each beam. Due to physical limitations, this method may use six transducer elements for each beam at the outer edge of the array sensor 30, compared to using twelve transducer elements for each beam at the center of the array sensor.

[0087] The X position of the array sensor 30 is measured by an X-axis displacement encoder 74, which encodes the rotation of an encoder wheel (not shown) mounted on a bracket to the radius scanner platform 70. As the radius scanner platform 70 travels radially, the encoder wheel travels across the surface of the component. After each incremental movement of the radius scanner platform 70 in the X direction, the X-axis displacement encoder 74 sends encoder pulses to a control computer 84, which are used by the control computer 84 and by an ultrasonic pulse generator / receiver device 82 to determine the X coordinate of each scanning plane in a known manner.

[0088] For a specific application involving the inspection of the soft tool radius of an integrally reinforced wing box, the aforementioned ultrasonic data acquisition / analysis system can be integrated into a non-destructive inspection system. This system includes: an active trailer carrying one or more array sensors for inspecting the soft tool radius; an external motorized tractor for moving the active trailer through the wing box's passageway; one or more ultrasonic pulse generators / receivers connected to the array sensors; a computer equipped with ultrasonic analysis, data acquisition, and motion control software; and a monitor for displaying C-scan images of the inspected component.

[0089] The teachings disclosed above can ultimately replace many unique NDI probe designs with a single probe design. This allows operators to scan the radius of wing panels or fuselage reinforcements without having to mechanically adjust the probe. As an example of cost savings, the inspection technique requiring three scans to check the radius of wing panel longitudinal spars can be replaced by a single-pass radius inspection method. Given the large number of composite reinforcements incorporated in some modern aircraft, the method disclosed herein can significantly reduce inspection costs.

[0090] Although methods and apparatus for ultrasound examination using composite components with multi-center radius focusing have been described with reference to various embodiments, those skilled in the art will understand that various changes can be made and equivalents can be substituted for their components without departing from the scope of the teachings herein. Furthermore, many modifications can be made to adapt the teachings herein to specific situations without departing from the scope of the invention. Therefore, it is intended that the claims are not limited to the specific embodiments disclosed herein.

[0091] The embodiments disclosed above use one or more computer systems. As used herein, the term "computer system" includes a single or multiple processing or computing devices that communicate via electrical conductors or wireless transmissions. Such processing or computing devices typically include one or more of the following: processor, controller, central processing unit, microcontroller, reduced instruction set computer processor, application-specific integrated circuit, programmable logic circuit, field-programmable gate array, digital signal processor, and / or any other circuitry or processing means capable of performing the functions described herein.

[0092] The methods described herein can be encoded as executable instructions embodied in a non-transitory tangible computer-readable storage medium, including but not limited to storage devices and / or memory devices. When executed by a processing or computing system, such instructions cause a system device to perform at least a portion of the methods described herein.

[0093] Furthermore, this disclosure includes embodiments according to the following provisions:

[0094] Clause 1. A method for inspecting rounded corner portions (10, 22), said rounded corner portions having a first flat surface and a second flat surface (24, 28) connected by rounded corner surfaces (26) and not parallel, said method comprising:

[0095] (a) The probe body (40) is placed in a position relative to the rounded portion such that the scanning plane of the array sensor (30, 46) including multiple transducer elements (32) and supported by the probe body intersects with and is perpendicular to the longitudinal axis of the rounded surface.

[0096] (b) Pulsating the corresponding apertures of the transducer elements of the array sensor to transmit a first plurality of beams (36) focused at a first focal point (FP1) and turned at a corresponding turning angle in the scanning plane, the first plurality of beams striking the corresponding regions of the rounded surface;

[0097] (c) After each of the first plurality of beams has been emitted, the transducer output signal from the transducer element of each aperture is processed to derive a corresponding parameter value, which characterizes the intensity of the corresponding echo returning from the rounded portion after each of the first plurality of beams impacts the rounded surface.

[0098] (d) Pulsating the corresponding apertures of the transducer elements of the array sensor to transmit a second plurality of beams (36) focused at a second focal point (FP2) and steered at a corresponding steer angle in the scanning plane, the second plurality of beams striking corresponding areas of the rounded surface; and

[0099] (e) After each of the second plurality of beams has been transmitted, the transducer output signal from the transducer element of each aperture is processed to derive a corresponding parameter value, which characterizes the intensity of the corresponding echo returning from the rounded portion after each of the second plurality of beams impacts the rounded surface.

[0100] The first focus is juxtaposed at the first curvature center of a first arc having a first radius, the second focus is juxtaposed at the second curvature center of a second arc having a second radius different from the first radius, and the first and second arcs are calculated in the reference frame of the rounded portion such that the first and second flat surfaces of the rounded portion are tangent to each of the first and second arcs.

[0101] Clause 2. The method as described in Clause 1, the method further comprising:

[0102] (e) Pulsating the corresponding apertures of the transducer elements of the array sensor to transmit a third plurality of beams focused at a third focal point and steered at a corresponding angle in the scanning plane, the third plurality of beams striking corresponding areas of the rounded surface; and

[0103] (f) After each of the third plurality of beams has been transmitted, the transducer output signal from the transducer element of each aperture is processed to derive a corresponding parameter value, which characterizes the intensity of the corresponding echo returning from the rounded portion after each of the third plurality of beams has struck the rounded surface.

[0104] The third focus is juxtaposed at the center of the third curvature of a third arc having a third radius different from the first and second radii, and the third arc is calculated in the reference frame of the rounded portion such that the first and second flat surfaces of the rounded portion are tangent to the third arc.

[0105] Clause 3. The method as described in Clause 2, wherein the first radius and the second radius differ by a first incremental radius, the first radius and the third radius differ by a second incremental radius, and the first incremental radius is equal to the second incremental radius.

[0106] Clause 4. The method as described in Clause 1, wherein the parameter is amplitude.

[0107] Clause 5. The method as described in Clause 1, the method further comprising:

[0108] Determine the range of variation of the radius of the rounded corner surface, which includes the first radius and the second radius that differ by an increment radius;

[0109] If the radius of the rounded corner surface is the first radius, then the first focus is positioned at the location where the center of the first arc representing the contour of the rounded corner surface would be located; and

[0110] If the radius of the rounded surface is the second radius, then the second focus is located at the position where the center of the second arc representing the contour of the rounded surface will be located.

[0111] Clause 6. The method as described in Clause 1, wherein the array sensor of the transducer element is bent.

[0112] Clause 7. The method as described in Clause 1, wherein the array sensor of the transducer element is linear.

[0113] Clause 8. The method as described in Clause 1, wherein the rounded corner surface is recessed.

[0114] Clause 9. The method as described in Clause 1, wherein the rounded corner surface is raised.

[0115] Clause 10. An apparatus for inspecting rounded corner portions, said apparatus comprising:

[0116] An array sensor (30) including multiple transducer elements (32);

[0117] The probe body (40) of the array sensor is held in place; and

[0118] A pulse generator / receiver device (82) programmed to perform operations including:

[0119] (a) The transducer elements of the array sensor are pulsed according to a first transmission focusing law, which is calculated such that the array sensor emits a first beam focused at a first focal point (FP1) located along the centerline of the array sensor.

[0120] (b) After the first beam is emitted, the transducer output signal from the transducer element is processed according to a first receiving focusing law, the first receiving focusing law being calculated such that the array sensor derives a first parameter value, the first parameter value being characterizing the intensity of the echo received after the first beam strikes the rounded surface of the rounded portion.

[0121] (c) Pulsating the transducer elements of the array sensor according to a second transmission focusing law, the second transmission focusing law being calculated such that the array sensor emits a second beam focused at a second focal point (FP2) located along the centerline of the array sensor; and

[0122] (d) After the second beam is emitted, the transducer output signal from the transducer element is processed according to a second receiving focusing law, which is calculated such that the array sensor derives a second parameter value, the second parameter value representing the intensity of the echo received after the second beam impacts the rounded surface.

[0123] The first focal point is located at a first distance from the center of the array sensor, and the second focal point is located at a second distance from the center of the array sensor, the second distance being different from the first distance.

[0124] Clause 11. The device as described in Clause 10, wherein the pulse generator / receiver device is further programmed to perform operations including:

[0125] (e) Pulsating the transducer elements of the array sensor according to the third transmission focusing law, the third transmission focusing law being calculated such that the array sensor emits a third beam focused at a third focal point located along the centerline of the array sensor; and

[0126] (f) After the third beam is emitted, the transducer output signal from the transducer element is processed according to a third receiving focusing law, which is calculated such that the array sensor derives a third parameter value, which characterizes the intensity of the echo received after the third beam strikes the rounded surface.

[0127] The third focal point is located at a third distance from the center of the array sensor, and the third distance is different from the first distance and the second distance.

[0128] Clause 12. The device as described in Clause 10, wherein the array sensor of the transducer element is bent.

[0129] Article 13. The device as described in Clause 10, wherein the array sensor of the transducer element is linear.

[0130] Clause 14. The device as described in Clause 10, wherein the probe body is designed for the maximum radius of the rounded surface to allow inspection of the smaller radius of the rounded surface without any mechanical adjustment.

[0131] Clause 15. The apparatus as described in Clause 10 further includes a non-transitory tangible computer-readable storage medium (88) for storing a file containing digital data representing the first transmission focusing law and the second transmission focusing law, as well as the first receiving focusing law and the second receiving focusing law.

[0132] Clause 16. A method for inspecting rounded corner portions, the method comprising:

[0133] (a) Generate a cross-sectional model of a probe (30, 40, 46) in contact with the rounded portions (10, 22) of a first surface and a second surface (24, 28) connected by a rounded surface (26), the probe including an array of sensors (30, 46) of transducer elements (32), the cross-sectional model including a first line and a second line representing the respective contours of the first surface and the second surface, and a plurality of arcs spanning a range of expected variation of the radius of the rounded surface of the rounded portions, each of the arcs terminating at the first line and the second line;

[0134] (b) Calculate a set of transmission focusing laws, which, when executed, will cause the array sensor to emit a plurality of beams (36) focused at a plurality of focal points at different distances from the center of the array sensor, wherein the plurality of focal points correspond to the respective centers of the plurality of arcs at different distances from the center of the analog array sensor of the transducer element;

[0135] (c) Calculate a set of receiving focusing laws, which are designed such that the array sensor derives multiple parameter values ​​that characterize the intensity of the echo received after the multiple beams strike the rounded surface of the rounded portion.

[0136] (d) The probe is placed in a position relative to the rounded portion, the position being consistent with the relative position represented by the cross-sectional model;

[0137] (e) Pulsating the corresponding apertures of the transducer elements of the array sensor according to the set of transmission focusing laws to transmit multiple beams focused at the plurality of focal points; and

[0138] (f) After each of the plurality of beams is emitted, the transducer output signal from the transducer element is processed according to the set of receiving focusing laws to derive a set of parameter values ​​characterizing the intensity of the echo received after the plurality of beams strike the rounded surface of the rounded portion.

[0139] Clause 17. The method as described in Clause 16, wherein the arcs in the plurality of arcs have different radii.

[0140] Clause 18. The method as described in Clause 17, wherein the different radii include a first radius, a second radius that is an increment radius larger than the first radius, and a third radius that is an increment radius larger than the second radius.

[0141] Clause 19. The method as described in Clause 16, wherein the parameter is amplitude.

[0142] Clause 20. The method as described in Clause 16, wherein the time delay of the transmission focusing law is derived from a trigonometric identity relative to the center of the simulated array sensor.

[0143] The appended detailed process claims should not be construed as requiring that they be described in alphabetical order (any alphabetical order in the claims is for the purpose of referring to the previously described steps only) unless the language of the claims expressly specifies or states a condition indicating that some or all of those steps shall be performed in that order. Nor should process claims be construed as excluding any portion of two or more steps that are performed simultaneously or alternately, unless the language of the claims expressly states a condition excluding such an interpretation.

Claims

1. A method for inspecting rounded corner portions (10, 22), the rounded corner portions having a first flat surface and a second flat surface (24, 28) connected by rounded corner surfaces (26) and not parallel, the method comprising: (a) The probe body (40) is placed in a position relative to the rounded portion that conforms to the relative position represented by the cross-sectional model, such that the scanning plane of the curved array sensor, which includes multiple transducer elements (32) and is supported by the probe body, intersects with and is perpendicular to the longitudinal axis of the rounded surface, wherein the position of the array sensor is not concentric with the rounded surface. (b) Pulsating the corresponding apertures of the transducer elements of the array sensor according to the first transmission focusing law in a set of transmission focusing laws, the first transmission focusing law being calculated such that the array sensor transmits and focuses at a first focal point (FP1) and is directed in the scanning plane at a corresponding turning angle to a first plurality of beams (36), the first plurality of beams striking the corresponding regions of the rounded surface. (c) After each of the first plurality of beams has been transmitted, the transducer output signal from the transducer element of each aperture is processed according to a first receiving focusing law in a set of receiving focusing laws, the first receiving focusing law being calculated such that the array sensor derives a corresponding parameter value characterizing the intensity of the corresponding echo returning from the rounded portion after each of the first plurality of beams strikes the rounded surface. (d) Pulsate the corresponding aperture of the transducer element of the array sensor according to the second transmission focusing law in a set of transmission focusing laws to transmit and focus a second plurality of beams (36) at the second focal point (FP2) and turn in the scanning plane at a corresponding turning angle, the second plurality of beams striking the corresponding area of ​​the rounded surface; as well as (e) After each of the second plurality of beams has been transmitted, the transducer output signal from the transducer element of each aperture is processed according to a second receiving focusing law, which is calculated such that the array sensor derives a corresponding parameter value characterizing the intensity of the corresponding echo returning from the rounded portion after each of the second plurality of beams strikes the rounded surface. The first focus is juxtaposed at the first curvature center of a first arc having a first radius, the second focus is juxtaposed at the second curvature center of a second arc having a second radius different from the first radius, and the first arc and the second arc are calculated in the reference frame of the rounded portion such that the first flat surface and the second flat surface of the rounded portion are tangent to each of the first arc and the second arc. Prior to the step of placing the probe body (40) in a position relative to the rounded corner portion, the method further includes: (a1) Generate a cross-sectional model of a probe (40) that contacts the rounded portions (10, 22) of a first flat surface and a second flat surface (24, 28) connected by a rounded surface (26), the probe comprising an array sensor of transducer elements (32), the cross-sectional model comprising a first line and a second line representing the respective contours of the first flat surface and the second flat surface, and a plurality of arcs spanning a range of expected variation of the radius of the rounded surface of the rounded portions, each of the arcs terminating at the first line and the second line; (b1) Calculate the set of transmission focusing laws, which, when executed, will cause the array sensor to emit beams focused at multiple focal points located at different distances from the center of the array sensor, wherein the multiple focal points correspond to the respective centers of the multiple arcs located at different distances from the center of the simulated array sensor of the transducer element; and (c1) Calculate the set of receiving focusing laws, which are designed such that the array sensor derives multiple parameter values ​​characterizing the intensity of the echo received after the plurality of beams on the rounded surface strike the rounded portion.

2. The method of claim 1, further comprising: (e) Pulsating the corresponding apertures of the transducer elements of the array sensor to transmit a third plurality of beams focused at a third focal point and steered at a corresponding steer angle in the scanning plane, the third plurality of beams striking the corresponding regions of the rounded surface. as well as (f) After each of the third plurality of beams has been transmitted, the transducer output signal from the transducer element of each aperture is processed to derive a corresponding parameter value characterizing the intensity of the corresponding echo returning from the rounded portion after each of the third plurality of beams has struck the rounded surface. The third focus is juxtaposed at the center of the third curvature of a third arc having a third radius different from the first and second radii, and the third arc is calculated in the reference frame of the rounded portion such that the first and second flat surfaces of the rounded portion are tangent to the third arc.

3. The method of claim 2, wherein the first radius and the second radius differ by a first incremental radius, the first radius and the third radius differ by a second incremental radius, and the first incremental radius is equal to the second incremental radius.

4. The method of claim 1 or 2, wherein the parameter is amplitude.

5. The method according to any one of claims 1-3, wherein the method further comprises: Determine the range of variation of the radius of the rounded corner surface, the range including the first radius and the second radius that differ by an increment radius; When the radius of the rounded corner surface is the first radius, the first focus is positioned at the location where the center of the first arc representing the contour of the rounded corner surface will be located; as well as When the radius of the rounded corner surface is the second radius, the second focus is positioned at the location where the center of the second arc representing the contour of the rounded corner surface will be located.

6. The method of any one of claims 1-3, wherein the rounded corner surface is recessed.

7. The method of any one of claims 1-3, wherein the rounded corner surface is raised.

8. An apparatus for inspecting rounded corner portions, the apparatus being arranged to perform the method according to any one of claims 1 to 7.

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