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Grigory I. Nesterenko - One of the best experts on this subject based on the ideXlab platform.

  • Russian Practice to Provide Safe Operation of Airplane Structures with Long-Term Operation
    ICAF 2019 – Structural Integrity in the Age of Additive Manufacturing, 2020
    Co-Authors: Boris G. Nesterenko, Viktorovich Vladimir Konovalov, Grigory I. Nesterenko, Vitaly Ya. Senik
    Abstract:

    The article presents some general approach to provide safe operation of aging aircraft structures including those with long-term operation (Fig.  1 ). Data on increased service life values of aged aircraft in Russia are given. Methods to detect and eliminate the structural corrosion Damages are discussed. Statistical data on distribution of typical defects in civil aircraft structures are given including some results on statistical analyses of the duration of corrosion depth increase in wing and fuselage skins of IL-86 wide-body passenger aircraft. Authors outline the approaches to prevent the failure of aircraft structures due to Widespread Fatigue Damage with provided statistics on the multiple site Fatigue Damages in panel joint of the upper wing surface of Il-62 M civil airplane that were identified while full-scale tests of aircraft and obtained from operation. In addition, the results of experimental research on degradation of strength, Fatigue, and crack growth resistance of long-term-operated airframes are given. Fig. 1. Compared operation time of Russian airplanes to their design goals. Dotted lines correspond to individually extended service life fleet leaders

  • Russian Practice to Provide Safe Operation of Airplane Structures with Long-Term Operation
    ICAF 2019 – Structural Integrity in the Age of Additive Manufacturing, 2019
    Co-Authors: Boris G. Nesterenko, Viktorovich Vladimir Konovalov, Grigory I. Nesterenko, Vitaly Ya. Senik
    Abstract:

    The article presents some general approach to provide safe operation of aging aircraft structures including those with long-term operation (Fig. 1). Data on increased service life values of aged aircraft in Russia are given. Methods to detect and eliminate the structural corrosion Damages are discussed. Statistical data on distribution of typical defects in civil aircraft structures are given including some results on statistical analyses of the duration of corrosion depth increase in wing and fuselage skins of IL-86 wide-body passenger aircraft. Authors outline the approaches to prevent the failure of aircraft structures due to Widespread Fatigue Damage with provided statistics on the multiple site Fatigue Damages in panel joint of the upper wing surface of Il-62 M civil airplane that were identified while full-scale tests of aircraft and obtained from operation. In addition, the results of experimental research on degradation of strength, Fatigue, and crack growth resistance of long-term-operated airframes are given. Open image in new window Fig. 1. Compared operation time of Russian airplanes to their design goals. Dotted lines correspond to individually extended service life fleet leaders

  • Service Life Investigation for Aging Aircraft.
    1997
    Co-Authors: Grigory I. Nesterenko
    Abstract:

    Abstract : This report results from a contract tasking TsAGI as follows: The contractor will report on investigation into structural issues effecting aging aircraft. One of the most important problems in aviation is the one of ensuring safe operation of aging aircraft. Up to date many Russian aircraft types have worked out their design service lives. It is impossible to replace all of old aircraft types by newer ones in the nearest future, so it seems obligatory to prolong service lives and durability of aging aircraft beyond the design goals. This requires testing the long-operated aircraft for Fatigue resistance, ensuring Damage tolerance of the structures with Widespread Fatigue Damage (WFD), studying the degradation of crack resistance and Fatigue strength after long-term operation, and ensuring safe operation of corrosion-Damaged structures. This paper outlines the experience of dealing with the above problems in Russia.

Vitaly Ya. Senik - One of the best experts on this subject based on the ideXlab platform.

  • Russian Practice to Provide Safe Operation of Airplane Structures with Long-Term Operation
    ICAF 2019 – Structural Integrity in the Age of Additive Manufacturing, 2020
    Co-Authors: Boris G. Nesterenko, Viktorovich Vladimir Konovalov, Grigory I. Nesterenko, Vitaly Ya. Senik
    Abstract:

    The article presents some general approach to provide safe operation of aging aircraft structures including those with long-term operation (Fig.  1 ). Data on increased service life values of aged aircraft in Russia are given. Methods to detect and eliminate the structural corrosion Damages are discussed. Statistical data on distribution of typical defects in civil aircraft structures are given including some results on statistical analyses of the duration of corrosion depth increase in wing and fuselage skins of IL-86 wide-body passenger aircraft. Authors outline the approaches to prevent the failure of aircraft structures due to Widespread Fatigue Damage with provided statistics on the multiple site Fatigue Damages in panel joint of the upper wing surface of Il-62 M civil airplane that were identified while full-scale tests of aircraft and obtained from operation. In addition, the results of experimental research on degradation of strength, Fatigue, and crack growth resistance of long-term-operated airframes are given. Fig. 1. Compared operation time of Russian airplanes to their design goals. Dotted lines correspond to individually extended service life fleet leaders

  • Russian Practice to Provide Safe Operation of Airplane Structures with Long-Term Operation
    ICAF 2019 – Structural Integrity in the Age of Additive Manufacturing, 2019
    Co-Authors: Boris G. Nesterenko, Viktorovich Vladimir Konovalov, Grigory I. Nesterenko, Vitaly Ya. Senik
    Abstract:

    The article presents some general approach to provide safe operation of aging aircraft structures including those with long-term operation (Fig. 1). Data on increased service life values of aged aircraft in Russia are given. Methods to detect and eliminate the structural corrosion Damages are discussed. Statistical data on distribution of typical defects in civil aircraft structures are given including some results on statistical analyses of the duration of corrosion depth increase in wing and fuselage skins of IL-86 wide-body passenger aircraft. Authors outline the approaches to prevent the failure of aircraft structures due to Widespread Fatigue Damage with provided statistics on the multiple site Fatigue Damages in panel joint of the upper wing surface of Il-62 M civil airplane that were identified while full-scale tests of aircraft and obtained from operation. In addition, the results of experimental research on degradation of strength, Fatigue, and crack growth resistance of long-term-operated airframes are given. Open image in new window Fig. 1. Compared operation time of Russian airplanes to their design goals. Dotted lines correspond to individually extended service life fleet leaders

Roman Krashanitsa - One of the best experts on this subject based on the ideXlab platform.

  • Probabilistic method for the analysis of Widespread Fatigue Damage in structures
    International Journal of Fatigue, 2005
    Co-Authors: Sergey Shkarayev, Roman Krashanitsa
    Abstract:

    A probabilistic method was developed to model structural failure associated with Widespread Damage as a stochastic chain of crack initiation and growth, linkup, and final failure. The major feature of this method is that multiple sites (fastener holes) have individual crack-initiation and crack-growth characteristics. These individual characteristics are established by Monte Carlo simulation. Stress analysis of unDamaged and cracked structures is performed incrementally using a finite element method incrementally and the crack length increment is determined at a given time increment by using an equation for crack growth. Consequent application of the Monte Carlo simulation results in empirical distributions for (a) life to crack initiation, (b) residual life and (c) total life of the structure. A worst-case scenario of multiple cracks is introduced by assigning equal cracks growing simultaneously with highest speed at all sites. This case establishes the threshold of residual life of a structure. Utilizing the threshold, Monte Carlo simulations are conducted in conjunction with a three-parameter lognormal probability distribution for the residual life of a structure. Numerical studies were performed for panels with rows of holes and for a panel stiffened by stringers. The proposed method makes it possible to assess the probability of occurrence of a structure's failure associated with Widespread Damage as a function of time.

John G. Bakuckas - One of the best experts on this subject based on the ideXlab platform.

  • DESTRUCTIVE EVALUATION AND EXTENDED Fatigue TESTING OF RETIRED AIRCRAFT FUSELAGE STRUCTURE
    2016
    Co-Authors: John G. Bakuckas, Aubrey Carter
    Abstract:

    The Federal Aviation Administration (FAA) and Delta Air Lines have teamed in an effort involving the inspection, teardown destructive evaluation, and extended Fatigue testing of fuselage structure removed from a retired passenger aircraft near its design service goal. This paper reports on the major activities for this project. Eleven large sections were removed from a Boeing 727 aircraft representative of fuselage structure susceptible to Widespread Fatigue Damage (WFD). Detailed inspections using both conventional and emerging nondestructive inspection (NDI) methods were made before and after the removal of the sections. Seven sections will be destructively evaluated to characterize the state of multiple-site Damage (MSD) and multiple-element Damage in fuselage structure. A teardown procedure was developed to disassemble joints and reveal fracture surfaces at fasteners for Damage characterization. In the remaining four sections, the state of MSD will be advanced through extended Fatigue testing using the FAA Full-Scale Aircraft Structural Test Evaluation and Research facility and then assessed through teardown destructive evaluation. Extended Fatigue testing will provide data to enable calibration and validation of predictive methodologies for structural Fatigue and will serve as a test bed to evaluate the sensitivity and effectiveness of standard and emerging NDI to detect small cracks. The data generated from this project will be used for developing and assessing programs to preclude WFD in the commercial fleet.

  • Survey of Structural Repairs and Alterations in Transport Category Airplanes
    ICAF 2009 Bridging the Gap between Theory and Operational Practice, 2009
    Co-Authors: Michel D. Bode, Walter M. Sippel, John G. Bakuckas
    Abstract:

    The work presented here details a survey of structural repairs, alterations, and modifications (RAM) on transport airplanes that was conducted over the past year and a half as part of a two-year project. The goal of this effort is to provide data to better understand the risks that RAMs may pose for developing Widespread Fatigue Damage (WFD). Surveys were conducted on retired airplanes at aircraft salvage locations and on in-service airplanes at the operator’s heavy maintenance locations and will be compared to a similar survey conducted by the Airworthiness Assurance Working Group in the 1990s. Additionally, specimens from retired airplanes were acquired and in-depth teardown inspections were performed to look for the presence of Damage indicative of WFD. A database was developed to analyze the data for WFD risk assessments. Once completely populated, recorded data will be examined for trends to quantify the risks that RAMs may pose for developing WFD.

  • Fatigue Testing of a Stiffened Lap Joint Curved Fuselage Structure
    Journal of Aircraft, 2007
    Co-Authors: Abubaker Ahmed, John G. Bakuckas, Jonathan Awerbuch, A.c.w. Lau, Tein-min Tan
    Abstract:

    In April 1988, Aloha Airlines flight 243 experienced an explosive midair decompression that resulted in the separation of an 18-foot section of the fuselage crown of the Boeing 737 airplane. Investigations revealed that the linkup of small cracks emanating from multiple rivet holes in a debonded lap joint contributed to the catastrophic failure. This cracking scenario, known as multiple-site Damage, is one of two sources of Widespread Fatigue Damage; a type of structural degradation characterized by the simultaneous presence of Fatigue cracks at multiple structural elements that are of sufficient size and density whereby the structure will no longer meet its Damage tolerance requirement This study, sponsored by the National Aging Aircraft Research Program initiated by the Federal Aviation Administration in response to the Aloha accident, investigates multiple-site Damage initiation and growth behavior in a pristine narrow-body fuselage panel. The test panel, a curved 6 x 10 ft stiffened structure containing six frames, seven stringers, and a longitudinal lap joint, was tested at the Federal Aviation Administration Full-Scale Aircraft Structural Test Evaluation and Research facility. The panel was subjected to a Fatigue test with constant-amplitude cyclic loading, simulating the major modes of load associated with fuselage pressurization. Nondestructive inspections were conducted during the Fatigue test to detect and monitor crack formation and growth. Multiple-site Damage cracks were visually detected after about 80% of the Fatigue life. Cracks developed and linked in the upper rivet row of the lap joint in the outer skin layer and formed a long Fatigue crack before the termination of the Fatigue test A residual strength test was then conducted by subjecting the panel to quasi-static loads until catastrophic failure. Fractographic examinations were conducted to reconstruct crack growth history. Preliminary results show multiple crack origins and significant subsurface crack growth.

  • Widespread Fatigue Damage Assessment Approach
    2001
    Co-Authors: Paul W. Tan, Catherine A. Bigelow, John G. Bakuckas, William J. Hughes
    Abstract:

    A methodology to assess the development of Widespread Fatigue Damage (WFD) and its effect on the residual strength of aircraft structure has been developed. The three major components of the methodology are crack initiation, crack growth and linkup, and residual strength. The crack initiation methodology uses experimentally generated equivalent initial flaw size (EIFS) data and an analytical closure model to determine initial flaw sizes and distribution for multiple-site cracking. The crack-tip opening angle (CTOA) and the T* integral, and plastic zone touch (PZT) criteria were used to predict crack growth and linkup. Elastic-plastic finite element analyses were used with the CTOA or T* integral to determine the residual strength in the presence of multiple-site Damage (MSD). The methodologies were verified through a comprehensive test program. 1. Introduction In response to public concerns after the Aloha Accident, Congress passed legislation known as the Aviation Safety Research Act of 1988. The Act directs the FAA to develop technologies and conduct data analyses for predicting the effects of aircraft design, maintenance, testing, wear, and Fatigue on the life of aircraft and on air safety and to develop methods of analyzing and improving aircraft maintenance technology and practices, including nondestructive inspection (NDI) of aircraft structures. The Act also includes a requirement to develop a better understanding of the relationship between human factors and aviation safety and to identify innovative and effective corrective measures for human errors that could adversely affect air safety. As a result of the Aviation Safety Research Act and concerns relating to the increasing age of the air carrier fleet, the Federal Aviation Administration (FAA) developed the National Aging Aircraft Research Program (NAARP) to ensure the structural integrity of high-time, high-cycle aircraft. Within the NAARP, the FAA is actively pursuing research to address the problems associated with ensuring the continued structural integrity of the aging commercial transport fleet. The NAARP structural integrity research and development program area includes three major elements: methodologies to assess Widespread Fatigue Damage, airframe repair assessment, and supplemental structural inspections for commuter aircraft. This paper discusses the first element, the assessment of Widespread Fatigue Damage.

  • Boundary Correction Factors for Elliptical Surface Cracks Emanating from Countersunk Rivet Holes
    AIAA Journal, 2000
    Co-Authors: Anisur Rahman, John G. Bakuckas, Catherine A. Bigelow, Paul W. Tan
    Abstract:

    To predict the crack growth and residual strength of riveted joints subjected to Widespread Fatigue Damage, accurate stress and fracture analyses of corner and surface cracks at a rivet hole are needed. The results presented focus on the calculation of stress-intensity factor (SIF) solutions for cracks at countersunk rivet holes for tension, bending, and wedge load conditions. A wide range of configuration parameters were varied, including the crack size, crack shape, crack location, and length of the straight shank hole. A finite-element-based global-intermediatelocal hierarchical approach was used. The results are expressed as boundary correction factors (BCFs), which are nondimensional representations of the SIF. The BCFs were determined along the crack front in terms of the physical angle, which was measured from the inner surface of the plate to a point on the hole boundary or on the outer surface of the plate. In general, the values of BCFs increased along the crack front, moving from the inner surface of the plate toward the hole boundary or the outer surface. The values of the BCFs were highest for the crack fronts closest to the hole boundary. The trends in the solutions were the same for the three loading conditions.

Charles E. Harris - One of the best experts on this subject based on the ideXlab platform.

  • Jim Starnes' Contributions to Residual Strength Analysis Methods for Metallic Structures
    46th AIAA ASME ASCE AHS ASC Structures Structural Dynamics and Materials Conference, 2005
    Co-Authors: Richard D. Young, Cheryl A. Rose, Charles E. Harris
    Abstract:

    A summary of advances in residual strength analyses methods for metallic structures that were realized under the leadership of Dr. James H. Starnes, Jr., is presented. The majority of research led by Dr. Starnes in this area was conducted in the 1990's under the NASA Airframe Structural Integrity Program (NASIP). Dr. Starnes, respectfully referred to herein as Jim, had a passion for studying complex response phenomena and dedicated a significant amount of research effort toward advancing Damage tolerance and residual strength analysis methods for metallic structures. Jim's efforts were focused on understanding Damage propagation in built-up fuselage structure with Widespread Fatigue Damage, with the goal of ensuring safety in the aging international commercial transport fleet. Jim's major contributions in this research area were in identifying the effects of combined internal pressure and mechanical loads, and geometric nonlinearity, on the response of built-up structures with Damage. Analytical and experimental technical results are presented to demonstrate the breadth and rigor of the research conducted in this technical area. Technical results presented herein are drawn exclusively from papers where Jim was a co-author.

  • Methodology for Predicting the Onset of Widespread Fatigue Damage in Lap-Splice Joints
    1998
    Co-Authors: James C. Newman, Charles E. Harris, Rs Piascik, D S Dawicke
    Abstract:

    NASA has conducted an Airframe Structural Integrity Program to develop the methodology to predict the onset of Widespread Fatigue Damage to lap-splice joints of fuselage structures. Several stress analysis codes have been developed or enhanced to analyze the lap-splice-joint configuration. Fatigue lives in lap-splice-joint specimens and Fatigue-crack growth in a structural Fatigue test article agreed well with calculations from small-crack theory and Fatigue-crack growth analyses with the FASTRAN code. Residual-strength analyses of laboratory specimens and wide stiffened panels were predicted quite well from the critical crack-tip-opening angle (CTOA) fracture criterion and elastic-plastic finite-element analyses (two- or three-dimensional codes and the STAGS shell code).

  • Analytical Methodology for Predicting Widespread Fatigue Damage Onset in Fuselage Structure
    Journal of Aircraft, 1998
    Co-Authors: Charles E. Harris, James C. Newman, Robert S Piascik, James H. Starnes
    Abstract:

    A comprehensive analytical methodology has been developed for predicting the onset of Widespread Fatigue Damage (WFD) in fuselage structure. The determination of the number of e ights and operational hours of aircraft service life that are related to the onset of WFD includes analyses for crack initiation, Fatigue crack growth, and residual strength. Therefore, the computational capability required to predict analytically the onset of WFD must be able to represent a wide range of crack sizes, from the material (microscale) level to the global (structural-scale ) level. The results of carefully conducted teardown examinations of aircraft components indicate that Fatigue crack behavior can be represented conveniently by the following three analysis scales: 1 ) small three-dimensional cracks at the microscale level, 2 ) through-the-thickness two-dimensional cracks at the local structural level, and 3 ) long cracks at the global structural level. The computational requirements for each of these three analysis scales are described in this paper.

  • analytical methodology for predicting the onset of Widespread Fatigue Damage in fuselage structure
    1996
    Co-Authors: Charles E. Harris, James C. Newman, Robert S Piascik, James H. Starnes
    Abstract:

    NASA has developed a comprehensive analytical methodology for predicting the onset of Widespread Fatigue Damage in fuselage structure. The determination of the number of flights and operational hours of aircraft service life that are related to the onset of Widespread Fatigue Damage includes analyses for crack initiation, Fatigue crack growth, and residual strength. Therefore, the computational capability required to predict analytically the onset of Widespread Fatigue Damage must be able to represent a wide range of crack sizes from the material (microscale) level to the global structural-scale level. NASA studies indicate that the Fatigue crack behavior in aircraft structure can be represented conveniently by the following three analysis scales: small three-dimensional cracks at the microscale level, through-the-thickness two-dimensional cracks at the local structural level, and long cracks at the global structural level. The computational requirements for each of these three analysis scales are described in this paper.

  • Development of advanced structural analysis methodologies for predicting Widespread Fatigue Damage in aircraft structures
    1995
    Co-Authors: Charles E. Harris, James H. Starnes, James C. Newman
    Abstract:

    NASA is developing a 'tool box' that includes a number of advanced structural analysis computer codes which, taken together, represent the comprehensive fracture mechanics capability required to predict the onset of Widespread Fatigue Damage. These structural analysis tools have complementary and specialized capabilities ranging from a finite-element-based stress-analysis code for two- and three-dimensional built-up structures with cracks to a Fatigue and fracture analysis code that uses stress-intensity factors and material-property data found in 'look-up' tables or from equations. NASA is conducting critical experiments necessary to verify the predictive capabilities of the codes, and these tests represent a first step in the technology-validation and industry-acceptance processes. NASA has established cooperative programs with aircraft manufacturers to facilitate the comprehensive transfer of this technology by making these advanced structural analysis codes available to industry.