Patent Application
20100250148
The present disclosure is generally directed to NDE (non-destructive evaluation) methods for assessment and repair of damage to composite structures. More particularly, the present disclosure is generally directed to a deterministic NDE approach which utilizes direct qualitative non-destructive damage and degradation input to structural models for engineering-based performance prediction.
Current NDE of damage and repairs to composite materials includes many techniques including ultrasonic, optical and visual methods for certification. The evaluations may be carried out on the factory floor and in field inspection to evaluate the soundness of just-manufactured structures as well as any damage that occurs during aircraft build and field usage.
Current NDE approaches may involve historical and conservative accept/reject criteria and may be found in Structural Repair Manuals and in other governing documents. However, the accept/reject criteria used in current NDE approaches may not be based on direct correlation of defect/indication to strength or the existing life of the structure. Consequently, the criteria may translate directly to escapements and false calls; may lead to the conservative repair approach which may require that a scratch be treated the same as a thru-hole in the structure; and may lead to the repair of structures that do not require repair or to the over-designing of repairs. Once repaired, small defects or porosity in a repair may require a structurally safe repair to be removed and re-done at great cost in time and money.
Therefore, composite rapid repair assessment and verification methodologies are needed for composite aircraft and other composite structures.
The present disclosure is generally directed to a deterministic non-destructive evaluation system for composite damage assessment and repair. An illustrative embodiment of the system includes a structure of interest, non-destructive evaluation data and strength test data obtained on the structure of interest, finite element analysis performed on a structural model modified by the non-destructive data and the strength test data, a strength-to-indication correlation based on the finite element analysis and deterministic non-destructive evaluation predictions and recommendations based on the strength-to-indication correlation.
The present disclosure is further generally directed to a deterministic non-destructive evaluation method for composite damage assessment and repair. An illustrative embodiment of the method includes providing a structure, generating non-destructive evaluation data of the structure, generating strength-to-indication correlations and deterministic non-destructive evaluation results based on finite element analysis performed on a structural model modified by the non-destructive evaluation data and recommending a move-forward response based on the strength-to-indication correlations and deterministic non-destructive evaluation results.
The present disclosure is further generally directed to a deterministic non-destructive evaluation method for composite damage assessment and repair. An illustrative embodiment of the method includes providing a structure, generating non-destructive evaluation data of the structure, analyzing the non-destructive evaluation data of the structure, generating mechanical data by performing mechanical testing on the structure, performing finite element analysis on a structural model modified by the non-destructive evaluation data and the mechanical data, generating strength-to-indication correlations and deterministic non-destructive evaluation results based on the finite element analysis, inputting the strength-to-indication correlations and deterministic non-destructive evaluation results to input analysis tools and recommending a move-forward response based on the strength-to-indication correlations and deterministic non-destructive evaluation results.
The present disclosure is further generally directed to a deterministic non-destructive evaluation system for composite damage assessment and repair. An illustrative embodiment of the system includes a composite structure of interest; non-destructive evaluation data obtained by at least one of optical methods; ultrasonic methods and visual methods; strength test data obtained on the structure of interest by mechanical testing of the structure of interest; finite element analysis performed on a structural model modified by the non-destructive data and the strength test data; a strength-to-indication correlation based on the finite element analysis; and deterministic non-destructive evaluation predictions and recommendations based on the strength-to-indication correlation obtained using programmed correlations and a non-destructive evaluation analytical look-up table, a strength/load-carrying capacity-indication look-up table and a safety standards look-up table.
The present disclosure is further generally directed to a deterministic non-destructive evaluation method for composite damage assessment and repair. An illustrative embodiment of the method includes providing a composite structure; generating non-destructive evaluation data of the composite structure by at least one of ultrasonic methods, optical methods and visual methods; analyzing the non-destructive evaluation data of the composite structure; generating mechanical data by performing mechanical testing on the composite structure; performing finite element analysis on a structural model modified by the non-destructive evaluation data and the mechanical data; generating strength-to-indication correlations and deterministic non-destructive evaluation results based on the finite element analysis using a non-destructive evaluation analytical look-up table, a strength/load-carrying capacity-indication look-up table and a safety standards look-up table; inputting the strength-to-indication correlations and deterministic non-destructive evaluation results to input analysis tools; and recommending a move-forward response with respect to damage of the structure based on the strength-to-indication correlations and deterministic non-destructive evaluation results.
The following detailed description is merely exemplary in nature and is not intended to limit the described embodiments or the application and uses of the described embodiments. As used herein, the word “exemplary” or “illustrative” means “serving as an example, instance, or illustration.” Any implementation described herein as “exemplary” or “illustrative” is not necessarily to be construed as preferred or advantageous over other implementations. All of the implementations described below are exemplary implementations provided to enable persons skilled in the art to practice the disclosure and are not intended to limit the scope of the claims. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, brief summary or the following detailed description.
Referring initially to
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In block 214, the NDE results obtained in block 202 may be compared to the data in the NDE empirical/NDE analytical look-up table of block 208. In block 216, the NDE results may be compared to data in a strength/load carrying capacity-indication lookup table. In block 218, the NDE results may be compared to safety standards, SRMs, other existing standards and/or constraints data in a standards lookup table. In block 220, based on the comparisons carried out in blocks 214, 216 and 218, a pass/fail determination with margin of safety recommendation for further action may be made. In block 222, a determination may be made as to whether repairs to the structure of interest must be made. In the event that the structure of interest does not require repair and therefore passes the pass/fail determination in block 222, such may be reported back to the customer in block 224. In the event that the structure of interest does require repair and therefore does not pass the pass/fail determination in block 222, recommendation and/or guidance to a customer/repair team may be made in block 226. A repair may be made to the structure of interest in block 228. The method may then return to basic inspection of the structure of interest in block 202, after which the process may be repeated until the structure of interest does not require repair and thus passes the pass/fail inquiry posed in block 222. Accordingly, deterministic NDE may be used after repair of the structure of interest in block 228 as needed to provide quantitative prediction of the performance of the repair made in block 228.
Referring next to
The repair determination in block 306 may be initiated using a standard or traditional evaluation approach in block 310. In block 312, a damage parameters evaluation may be made using NDE analysis to determine the nature and extent of the damage to the vehicle. In block 314, a standard repair to the vehicle may be formulated. In block 316, the proposed repair to the vehicle may be implemented. In block 318, a standard NDE may be performed after repair of the vehicle.
In some applications, a workstation level analysis may be made in block 320 after the NDE damage parameters evaluation is carried out in block 312. In block 322, a detailed repair evaluation may be made. In block 324, a repair of the vehicle may be implemented. In block 326, a repair deterministic NDE may be performed after the repair is carried out in block 324.
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In block 522, a determination may be made as to whether standard repair techniques to the structure of interest are applicable based on the evaluation carried out in block 520. If standard repair techniques are not applicable, then the appropriate repair approach may be selected in block 524. These may include selection of a bonded repair technique in block 526 or selection of a bolted repair technique in block 528. If neither a bonded repair technique is selected in block 526 nor a bolted repair technique is selected in block 528, such may be reported back to the customer in block 530.
If a bonded repair technique is selected in block 526, bonded repair design and analysis may be carried out in block 532. A repair design may be made to the customer in block 534. In block 536, a determination may be made as to whether a deviation request was received from the customer. If yes, then an approved deviation may be developed in block 538. If no, then the bonded repair to the part may be implemented in block 540. In block 542, the repair implemented in block 540 may be assessed. In block 544, a determination may be made as to whether the repair meets all requirements. If no, then such may be reported back to the customer in block 546. If yes, then such may be reported back to the customer in block 548.
If a bonded repair technique is not selected in block 526, then a bolted repair technique may be selected in block 528. A bolted repair design and analysis may be carried out in block 550. A repair design may be made to the customer in block 534. In block 536, a determination may be made as to whether a deviation request was received from the customer. If yes, then an approved deviation may be developed in block 538. If no, then the bonded repair to the part may be implemented in block 540. In block 542, the repair implemented in block 540 may be assessed. In block 544, a determination may be made as to whether the repair meets all requirements. If no, then such may be reported back to the customer in block 546. If yes, then such may be reported back to the customer in block 548.
Referring next to
The data in blocks 602, 604, 606 and 608 may be provided to a deterministic effort (IRET) component 610. The deterministic effort 610 may include a performance-based deterministic NDE component 612. The performance-based deterministic NDE component 612 may include repair, NDE and maintenance documents and an acceptance standard module 614; analytical/empirical lookup tables 616; strength-defect lookup tables 618; and a processing and data transfer module 620.
In block 622, a determination may be made as to whether airworthiness requirements of the aircraft have been met based on the results of the performance-based deterministic NDE component in block 612. If yes, then such may be reported back to the customer in block 634. If no, then a repair evaluation may be made in block 624. A repair may be implemented in block 626. A repair assessment deterministic NDE may be made in block 628. In block 630, a determination may be made as to whether the repair meets all requirements. If yes, then such may be reported back to the customer in block 632.
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Each of the processes of method 78 may be performed or carried out by a system integrator, a third party, and/or an operator (e.g., a customer). For the purposes of this description, a system integrator may include without limitation any number of aircraft manufacturers and major-system subcontractors; a third party may include without limitation any number of vendors, subcontractors, and suppliers; and an operator may be an airline, leasing company, military entity, service organization, and so on.
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The apparatus embodied herein may be employed during any one or more of the stages of the production and service method 78. For example, components or subassemblies corresponding to production process 84 may be fabricated or manufactured in a manner similar to components or subassemblies produced while the aircraft 94 is in service. Also one or more apparatus embodiments may be utilized during the production stages 84 and 86, for example, by substantially expediting assembly of or reducing the cost of an aircraft 94. Similarly, one or more apparatus embodiments may be utilized while the aircraft 94 is in service, for example and without limitation, to maintenance and service 92.
Although the embodiments of this disclosure have been described with respect to certain exemplary embodiments, it is to be understood that the specific embodiments are for purposes of illustration and not limitation, as other variations will occur to those of skill in the art.
