METHOD FOR INSPECTING AN AERONAUTICAL COMPONENT

Abstract

A method for inspecting an aeronautical component, such as an aircraft turbomachine housing (10), comprising: a) a step of performing a three-dimensional scan of a surface (12) of the component, so as to obtain a digitized three-dimensional image of the surface and its defects; b) a computerized step of analyzing the three-dimensional image, and in particular the defects; c) a computerized step of determining several dimensional parameters relating to the defects; d) a computerized step of calculating an overall criticality of the defects, by comparing the calculated dimensional parameters with reference values ​​for these dimensional parameters; and e) a step of evaluating the component, based on the calculated overall criticality, in order to determine whether the component is compliant or non-compliant. Figure for the abstract: Figure 1

Description

Title of the invention: METHOD FOR INSPECTING AN AERONAUTICAL COMPONENT Technical field of the invention

[0001] The present invention relates to a method for inspecting an aeronautical part, such as an aircraft turbomachine housing. Technical background

[0002] Aeronautical parts generally require inspection to verify their conformity. This inspection may take place on a new part after its production, or on a part already used and mounted, for example on a turbomachine, this inspection then generally taking place during a maintenance operation.

[0003] This is particularly the case for a fan housing of an aircraft turbomachine. A fan casing is an annular-shaped housing that surrounds the turbomachine's fan. During operation, the casing is susceptible to projectiles such as birds, which can cause impacts on its internal surface. These impacts create defects in the form of dents. During maintenance, the fan casing is inspected to detect these defects and assess their severity.

[0004] In this application, "criticality" (or overall criticality) of a defect or defects means a scale for measuring the impact of a failure and therefore the level of acceptability of a risk.

[0005] In current technology, this inspection is carried out visually by a specialized operator. This inspection is therefore relatively long and complex. Furthermore, such an inspection presents a risk of misjudgment, particularly due to operator eye strain. The longer the inspection, the greater the maintenance and engine downtime, and therefore the more expensive the maintenance.

[0006] There is therefore a need to find a solution to make this type of inspection and control more reliable and faster.

[0007] The invention provides a solution to this need, which is simple, effective and economical. Summary of the invention

[0008] The invention relates to a method for inspecting an aeronautical part, such as an aircraft turbomachine housing, comprising:

[0009] a) a step of performing a three-dimensional scan of a surface of the aeronautical part, this surface having defects such as hollows, so as to obtaining a digitized three-dimensional image of the surface and its defects in the form of a multitude of surface points, called for example a point cloud,

[0010] b) a computerized step of analyzing the three-dimensional image, and in particular the defects,

[0011] c) a computerized step for determining several dimensional parameters relating to defects,

[0012] d) a computerized step for calculating the overall criticality of defects, by comparing the determined dimensional parameters with corresponding reference values ​​for these dimensional parameters, and

[0013] e) a step of evaluating the part, based on the calculated overall criticality, in order to determine whether the part is compliant or non-compliant.

[0014] The invention thus relates to a control method in which several steps can be computerized and therefore automated, in order to accelerate and improve the reliability of the control. In this application, "computerized" means that a step is carried out by a computer system. The computer system is then configured to control the execution of the step by, for example, controlling the various pieces of equipment necessary for its completion.

[0015] Step a) of the process consists of 3D scanning the surface to be inspected on the aeronautical part. This produces a 3D image of the surface in the form of a point cloud, the points being surface points such that the point cloud represents the relief or profile of this surface with its defects.

[0016] Step b) of the process consists in particular of analyzing the point cloud for example to distinguish the primary defects to be analyzed in more detail.

[0017] Step c) of the process allows several dimensional parameters of the defects to be determined, such as depth, length, etc.

[0018] Step d) of the process allows the overall criticality of the defects to be calculated, and step e) allows a conclusion to be drawn regarding the conformity or non-conformity of the aeronautical part based on this overall criticality. Step e) can be performed by an operator.

[0019] The method according to the invention may comprise one or more of the following features, taken individually or in combination with each other:

[0020] - step a) is carried out on a limited area of ​​the part, called the inspection area;

[0021] — the inspection area has a parallelogram shape and in particular a square shape;

[0022] — the inspection area has dimensions of 25cm x 25cm;

[0023] — any defects possibly detected outside the inspection area are ignored;

[0024] — the scan is performed by laser;

[0025] — the inspection area comprises more than 100 points, and by example between 200 and 800;

[0026] - step a) is preceded by a step i) of visual inspection, preferably complete, of the surface of the part so as to determine one or more inspection zones, the inspection zone or zones containing defects;

[0027] - step b) includes the detection, among all the defects, of primary defects;

[0028] - Primary defects are defects that have a depth greater than or equal to at a predetermined reference depth, for example before the implementation of the process;

[0029] — the reference depth is between 0.1 and 2 mm, preferably between 0.2mm and 1mm, and is for example equal to 0.5mm;

[0030] - step b) includes the distribution of primary defects in surfaces of reference, called islands, each of the islands having one or more adjacent primary defects;

[0031] - in step c), the dimensional parameters of the primary defects are chosen from the depth of each primary defect, the length of each primary defect, and the minimum distance between two adjacent primary defects;

[0032] — the dimensional parameters are determined in or from a plane of reference which is parallel to the surface of the part or tangent to the surface of the part at the level of the primary defect considered;

[0033] — the primary defects are numbered and each associated with a number;

[0034] - in step d), a weighting is assigned to each of the dimensional parameters based on the results of the comparison with the corresponding reference values ​​for these dimensional parameters;

[0035] - for each of the primary defects, the weightings of all the parameters Dimensional factors are added together to determine the criticality of the defect, this criticality being expressed, for example, as a percentage;

[0036] - the overall criticality of the defects is determined from the criticalities of all the primary defects;

[0037] — in step d), the reference values ​​are contained in a pre-established nomogram;

[0038] - step e) is carried out, preferably by an operator, by comparison of the overall criticality calculated with a reference criticality;

[0039] - the aeronautical part is an annular fan housing for a turbomachine aircraft;

[0040] - the process includes a step iii) of registering the three-dimensional image in a digital model of the aeronautical part, called a digital twin, so as to be able to visualize the multitude of points on the digital twin of the aeronautical part;

[0041] — the process includes a step ii) of providing identity information relating to the room;

[0042] - steps b), c) and d) are carried out automatically and allow obtaining an automated control report at the end of step d), which is used during step e);

[0043] — steps b), c) and d) are carried out using Polyworks® software.

[0044] The present invention also relates to an installation for implementing a process as described above, characterized in that it comprises a three-dimensional scanner configured to carry out step a) of the process, and a computer system configured to carry out at least steps b) to d) and to control the display of the calculated overall criticality.

[0045] The present invention further relates to a computer program downloadable from a communication network and / or stored on a computer-readable medium, characterized in that it comprises instructions for, when said program is executed on a computer system:

[0046] - order a three-dimensional scanner in order to carry out step a) of the process such that described above, then

[0047] - perform at least steps b), c) and d) of said process and control the display of the calculated overall criticality. Brief description of the figures

[0048] Other features and advantages of the invention will become apparent upon reading the detailed description that follows, for an understanding of which reference should be made to the accompanying drawings in which:

[0049] [Fig-1] [Fig.1] is a flowchart showing steps in a process according to the invention of a control system for an aeronautical part;

[0050] [Fig.2] [Fig.2] is a schematic perspective view of an aeronautical part and in particular a blower housing;

[0051] [Fig.3] [Fig.3] is a larger-scale view of part of [Fig.2] and shows defects on a surface of the part;

[0052] [Fig.4] [Fig.4] schematically shows a scatter plot in the sense of the invention;

[0053] [Fig.5] [Fig.5] is a schematic view of an inspection area;

[0054] [Fig.6] [Fig.6] is a schematic view of an identification card of the room;

[0055] [Fig.7] [Fig.7] is a very schematic view of an inspection area with defects and illustrates a step in the process;

[0056] [Fig.8] [Fig.8] is a very schematic view of an inspection area with defects and illustrates a step in the process;

[0057] [Fig.9] [Fig.9] is a very schematic view of defects and illustrates a step in the process;

[0058] [Fig. 10] [Fig. 10] is a table listing dimensional parameters of primary defects as well as the criticality of each of these primary defects; and

[0059] [Fig. 11] [Fig. 11] is a schematic view of an installation for implementing the process according to the invention. Detailed description of the invention

[0060] Fig. 1 is a flowchart that schematically shows an embodiment of a method for controlling an aeronautical part according to the invention.

[0061] The aeronautical part is, for example, a casing, in particular a fan casing, for an aircraft turbomachine. Figures 2 and 3 illustrate such a fan casing 10 (also referred to as "casing 10" in this description). The casing 10 has a generally annular shape around an axis A. This casing 10 includes an internal surface 12 that may have defects 14 such as impacts, which must be detected and analyzed during the casing 10 inspection process ([Fig. 3]).

[0062] The control process essentially comprises 5 steps, noted as steps a) to e), and may include other optional steps noted i), ii), etc.

[0063] Step a) of the control process is a step of carrying out a three-dimensional (3D) scan of a surface of the part, such as the surface 12 of the housing 10, this surface having defects such as hollows, so as to obtain a digitized three-dimensional image of the surface and its defects in the form of a multitude of surface points, called a point cloud 20.

[0064] Fig. 4 shows a scatter plot of 20 points which can be obtained at the end of this step a).

[0065] Step a) is preferably carried out on a limited area of ​​the part, called the inspection area. In the case of the housing in Figures 2 and 3, for example, only an inspection area Z of the surface can be inspected according to the method. It is therefore understood that only this inspection area Z is scanned in step a).

[0066] The inspection zone Z preferably has a simple geometric shape so that it can be easily delimited. Preferably, the inspection zone Z has the shape of a parallelogram and in particular a square.

[0067] The inspection zone Z has, for example, dimensions of 25 cm x 25 cm (centimeters).

[0068] The 3D scan is preferably performed by laser, and in particular by laser line(s). For example, it may consist of at least one laser line which scans the surface to be inspected and allows different points of the surface to be automatically recorded.

[0069] The 3D scan is preferably carried out using a 3D scanner such as the one marketed by the company FARO under the name Probe Laser Liben FAROBlu xR.

[0070] The 3D scan thus makes it possible to create a point cloud 20 corresponding to the relief or profile of the surface to be inspected. In the event that points are detected outside the inspection zone Z, these points could be ignored in order to limit the analysis of defects within this inspection zone Z.

[0071] Fig. 5 shows, for example, the inspection zone Z and some points which are located outside (around) this zone Z and which will be ignored.

[0072] The inspection zone Z may include a number of points greater than 100, and for example between 200 and 800.

[0073] As can be seen in [Fig. 1], the inspection process may include, before step a), a step i) of visual inspection, preferably complete, of the surface of the part so as to determine one or more inspection areas, the inspection area or areas having defects.

[0074] In the case of the housing 10 for example, it is understood that the operator visually checks the entire surface 12 before step a). During this inspection, he will detect defects and will decide which inspection zone Z or which inspection zones Z containing defects will / will have to be subject to a more thorough inspection according to steps a) and following.

[0075] The method may include, for example, before step a), a step ii) of entering identification information relating to the part. This information makes it possible to identify and trace the part. In the case of the housing 10, this could, for example, be a reference number for this housing, a reference number for the turbomachine incorporating this housing, information on the aircraft equipped with this turbomachine, information on the airline using this aircraft, etc. An identification card 30 for the part is then obtained, preferably in computerized form.

[0076] Fig. 6 illustrates such an identity card 30 which can be directly completed by an operator via a computer system.

[0077] The method may include, for example after step a), a step iii) of registering the three-dimensional image (point cloud) in a digital model of the part, called a digital twin, so as to be able to view the point cloud on the digital twin of the part.

[0078] This step is particularly advantageous for building a digital library of the most commonly inspected areas of a room and therefore the areas most often presenting defects. The digital library allows for the storage of feedback from previous inspections, which can facilitate and accelerate step i) mentioned above, for example.

[0079] Fig. 2 can be considered as illustrating this step iii). This figure allows visualization of the position and dimensions of the inspection zone Z on the housing 10.

[0080] Step iii) is carried out via a computer system.

[0081] The control process then comprises several steps b), c) and d) also carried out by a computer system and which allow for detailed analysis of the point cloud obtained in step a).

[0082] Step b) is a computerized step of three-dimensional image analysis, and in particular of defects.

[0083] Step b) may, for example, include the detection of primary defects among all the defects. Primary defects are, for example, defects that have a depth P (visible in [Fig. 7], for example) greater than or equal to a previously determined reference depth. The reference depth may be between 0.1 and 2 mm (millimeters), preferably between 0.2 mm and 1 mm, and is, for example, on the order of 0.5 mm.

[0084] Figure 7 schematically illustrates some defects 14 in an inspection zone Z. Among these defects 14, some have a depth P greater than the reference depth Pref and others do not. The primary defects (referenced 14' in Figure 7) having a depth greater than the reference depth will be analyzed in more detail later.

[0085] Step b) may include the distribution or allocation of primary defects to reference surfaces, called islands 22, each island having one or more adjacent primary defects ([Fig. 8]). The use of these islands can simplify the analysis of defects due to their distribution by reference surfaces.

[0086] Step c) is a computerized step for determining several dimensional parameters relating to defects, in particular primary defects.

[0087] In step c), the dimensional parameters of the primary defects can be chosen from the depth P of each primary defect, the length L of each primary defect, and the minimum distance Dmin between two adjacent primary defects ([Fig. 9]). Other dimensional parameters or different dimensional parameters could of course be measured.

[0088] These dimensional parameters are preferably determined in or from a reference plane Q which is parallel to the surface 12 of the part or tangent to the surface of the part at the level of the primary defect considered ([Fig.9]).

[0089] Step c) is advantageously carried out for each of the 22 islands identified in step b).

[0090] Primary defects can be numbered and each associated with a number XI, X2, etc., to identify and list them ([Fig.9]).

[0091] Step d) is a computerized step for calculating an overall criticality C of the defects, by comparing the dimensional parameters (P, L, Dmin, etc.) determined with reference values ​​for these dimensional parameters.

[0092] The reference values ​​are preferably contained in a pre-established nomogram.

[0093] For the determination of overall criticality, a weighting can be assigned to each of the dimensional parameters according to the results of the comparison with the reference values.

[0094] This weighting can be obtained using a nomogram, for example, in the form of a graph with several curves, each curve representing the evolution of the weighting (in %) of the criticality of a parameter as a function of the value of that parameter. For a given parameter, this type of nomogram thus makes it possible to provide the criticality weighting for each measured dimensional parameter.

[0095] The weights of all the dimensional parameters can then be added or averaged to determine the criticality C of each primary defect. This criticality is, for example, expressed as a percentage.

[0096] Fig. 10 illustrates an example of criticality C of each of the primary defects in an inspection zone Z, as a function of the comparison of the dimensional parameters (P, L, Dmin, etc.) determined with the reference values ​​of a nomogram.

[0097] The criticality values ​​C contained in the table in [Fig. 10] are averaged, for example, to calculate the overall criticality of the inspection area or the part under consideration. Alternatively, the maximum criticality C in the table in [Fig. 10] could be used as the overall criticality of the inspection area or the part under consideration. In this particular case, the average criticality is approximately 2.60% and the maximum criticality is 3.56%.

[0098] The method may include a step iv) of displaying the overall criticality calculated in step d), for example on a screen of the computer system. All or part of the information useful for calculating the criticality may be displayed, and for example the information contained in the table in [Fig. 10].

[0099] The process finally includes a step e) of evaluating the part, based on the calculated overall criticality, in order to determine whether the part is compliant or non-compliant.

[0100] Step e) can be carried out by an operator by comparing the calculated global criticality with a reference criticality.

[0101] In the case, for example, where the criticality of each of the defects of a part should not exceed 4%, the area inspected within the framework of the data in [Fig. 10] could be considered compliant because the criticality of all defects is less than 4%. If the inspected area is the only area of ​​the part, then the part can be declared compliant. If the part has other areas to be inspected, it must also be ensured that the criticality of the primary defects in these other areas is also less than 4%.

[0102] As mentioned above, steps b), c) and d) are preferably carried out automatically and allow an automated control report to be obtained at the end of step d), which is used in step e). These steps b), c) and d) are carried out for example using Polyworks® software.

[0103] The present invention also relates to an installation 30 for implementing the control method according to the invention, as illustrated in [Fig. 11].

[0104] The installation 30 includes a three-dimensional scanner 32 configured to carry out step a) of the process, and a computer system 34 configured to carry out at least steps b) to d) and control the display on a screen 36 of the calculated criticality C.

[0105] The computer system 34 includes, for example, a processor (which allows at least some steps of the control process to be implemented), a memory (which allows, for example, the storage of reference values), etc.

[0106] The invention further relates to a computer program downloadable from a communication network and / or stored on a computer-readable medium. This computer program includes instructions for, when said program is executed on the computer system 34:

[0107] - order the three-dimensional scanner 32 in order to carry out step a) of the process of control, then

[0108] - carry out at least steps b), c) and d) of the control process and order display of the calculated criticality.

Claims

Demands

1. A method for inspecting an aeronautical part, such as an aircraft turbomachine housing (10), comprising: a) a step of performing a three-dimensional scan of a surface (12) of the aeronautical part, this surface having defects (14) such as pits, so as to obtain a digitized three-dimensional image of the surface and its defects in the form of a multitude of surface points, b) a computerized step of analyzing the three-dimensional image, and in particular the defects, c) a computerized step of determining several dimensional parameters relating to the defects, d) a computerized step of calculating an overall criticality of the defects, by comparing the determined dimensional parameters with corresponding reference values ​​for these dimensional parameters, and e) a step of evaluating the part, based on the calculated overall criticality, in order to determine whether the part is compliant or non-compliant.

2. A method according to claim 1, wherein step a) is carried out on a limited area of ​​the part, called the inspection area (Z).

3. A method according to claim 1 or 2, wherein step a) is preceded by a step i) of visual inspection of the surface (12) of the part so as to determine one or more inspection zones (Z), the inspection zone or each inspection zone having defects.

4. A method according to any one of the preceding claims, wherein step b) comprises the detection, among all defects, of primary defects.

5. Method according to claim 4, wherein the primary defects are the defects which have a depth (P) greater than or equal to a previously determined reference depth (Pref).

6. A method according to claim 4 or 5, wherein, in step c), the dimensional parameters of the primary defects are chosen from the depth (P) of each primary defect, the length (L) of each primary defect, and the minimum distance (Dmin) between two adjacent primary defects.

7. A method according to any one of the preceding claims, wherein, in step d), a weighting is assigned to each of the dimensional parameters based on the results of the comparison with the corresponding reference values ​​for these dimensional parameters.

8. A method according to claim 7, wherein, for each of the primary defects, the weights of all the dimensional parameters are added together to determine a criticality of the defect, this criticality being expressed for example as a percentage.

9. A method according to claim 8, wherein the overall criticality of the defects is determined from the criticalities of all the primary defects.

10. A method according to any one of the preceding claims, wherein step e) is carried out by comparing the calculated global criticality with a reference criticality.

11. A method according to any one of the preceding claims, wherein the aeronautical part is an annular fan housing for an aircraft turbomachine.

12. A method according to any one of the preceding claims, wherein it includes a step iii) of registering the three-dimensional image in a digital model of the aeronautical part, called a digital twin, so as to be able to visualize the multitude of points on the digital twin of the aeronautical part.

13. A method according to any one of the preceding claims, wherein steps b), c) and d) are carried out automatically and allow an automated control report to be obtained at the end of step d), which is used in step e).

14. Installation (30) for carrying out a process according to any one of the preceding claims, characterized in that it comprises a three-dimensional scanner (32) configured to carry out step a) of the process, and a computer system (34) configured to carry out at least steps b) to d) and to display the calculated overall criticality.

15. A computer program downloadable from a communications network and / or stored on a computer-readable medium, characterized in that it includes instructions for, when said program is executed on a computer system (34): - order a three-dimensional scanner (32) in order to carry out step a) of the process according to one of the preceding claims, then - carry out at least steps b), c) and d) of said process and command the display of the calculated overall criticality.

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