damage tolerance

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Southwest Research Institute® (SwRI®) structural engineers per- form damage tolerance analysis for military and commercial aircraft to give clients the information neces- sary to safely and effectively manage the structural health of their fleets. SwRI has expertise using state-of- the-art tools such as AFGROW, NASGRO® and StressCheck® along with significant experience correlat- ing analyses to crack growth test results. Proficiency with automating these tools allows for efficient and timely results. Capabilities n Crack growth analysis software tools (AFGROW, NASGRO®, CRACKS, etc.) n Stress intensity calculation using finite element and boundary element tools (StressCheck®, NASBEM, etc.) n Correlation to spectrum test results from coupon and full- scale tests to determine crack growth rates and crack growth retardation due to spectrum effects n Automation for efficient and accu- rate analysis of large numbers of locations and/or variation of parameters n Stress determination using hand stress analysis and finite element tools such as FEMAP and NASTRAN n Risk and probabilistic crack growth analysis using state-of- the-art tools such as PROF and NESSUS® n Material, component and full- scale testing n Damage tolerance training/short course Aircraft Damage Tolerance Analysis D0 16014 KEYWORDS Aircraft Structures Fracture Mechanics Fatigue Crack Growth Damage Tolerance Durability Risk Analysis Stress Intensity Calculation Correlation to Test Results Crack Growth Retardation Automation of Analysis Residual Strength Finite Element Analysis Material Testing Component Test Full-Scale Test Southwest Research Institute ® Parametric finite element model (FEM) of countersunk hole crack stress intensity factors Spectrum test correlation using AFGROW for determination of retardation parameter 0 0.00 0.20 0.40 0.60 0.80 1.00 1.20 2,000 4,000 6,000 8,000 Time (flight hours) Crack Length (inches) 10,000 12,000 14,000 16,000 Test Specimen Analysis SOLR 1.89 D0 16015 Cracked aircraft structure image overlaid on finite element analysis (FEA) stress gradients D0 16016

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Damage Tolerance

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  • Southwest Research Institute (SwRI) structural engineers per-form damage tolerance analysis for military and commercial aircraft to give clients the information neces-sary to safely and effectively manage the structural health of their fleets. SwRI has expertise using state-of-the-art tools such as AFGROW, NASGRO and StressCheck along with significant experience correlat-ing analyses to crack growth test results. Proficiency with automating these tools allows for efficient and timely results.

    Capabilities

    n Crack growth analysis software tools (AFGROW, NASGRO, CRACKS, etc.) n Stress intensity calculation using finite element and boundary element tools (StressCheck, NASBEM, etc.)

    n Correlation to spectrum test results from coupon and full- scale tests to determine crack growth rates and crack growth retardation due to spectrum effects

    n Automation for efficient and accu- rate analysis of large numbers of locations and/or variation of parameters

    n Stress determination using hand stress analysis and finite element tools such as FEMAP and NASTRAN

    n Risk and probabilistic crack growth analysis using state-of- the-art tools such as PROF and NESSUS

    n Material, component and full- scale testing

    n Damage tolerance training/short course

    Aircraft DamageTolerance Analysis

    D0 1

    6014KEYWORDS

    Aircraft Structures

    Fracture Mechanics

    Fatigue Crack Growth

    Damage Tolerance

    Durability

    Risk Analysis

    Stress Intensity Calculation

    Correlation to Test Results

    Crack Growth Retardation

    Automation of Analysis

    Residual Strength

    Finite Element Analysis

    Material Testing

    Component Test

    Full-Scale Test

    SouthwestResearchInstitute

    Parametric finite element model (FEM) of countersunk hole crack stress intensity factors

    Spectrum test correlation using AFGROW for determination of retardation parameter

    00.00

    0.20

    0.40

    0.60

    0.80

    1.00

    1.20

    2,000 4,000 6,000 8,000

    Time (flight hours)

    Crac

    k Le

    ngth

    (inc

    hes)

    10,000 12,000 14,000 16,000

    Test Specimen

    Analysis SOLR 1.89

    D0 1

    6015

    Cracked aircraft structure image overlaid on finite element analysis (FEA) stress gradients

    D0 1

    6016

  • Benefiting government, industry and the public

    through innovative science and technology

    Luciano Smith, Senior Research Engineer David H. Wieland, Principal Engineer Aerospace Structures Aerospace Structures(210) 522-6857 (210) [email protected] [email protected]

    Structural Engineering DepartmentMechanical Engineering DivisionSouthwest Research Institute6220 Culebra Road (78238-5166)P.O. Drawer 28510 (78228-0510)San Antonio, Texas

    www.swri.orgwww.aerospacestructures.swri.org

    We welcomeyour inquiries.

    For additional information, please contact:

    An Equal Opportunity Employer M/F/D/VCommitted to Diversity in the Workplace

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    411

    JCN

    2406

    16 b

    l

    Experience

    SwRI has performed damage toler-ance and fatigue analysis for U.S. military aircraft (A-10, F-5, F-16, T-37, T-38) and for foreign military and commercial clients.

    Facilities and Analysis Tools

    SwRI uses state-of-the-art crack growth analysis tools such as NASGRO and AFGROW, as well as finite element modeling tools such as NASTRAN, FEMAP, and StressCheck for the determination of stresses and stress intensities. SwRI has facilities to perform tests on structures ranging from coupons to components to full-scale aircraft.

    Aircraft structure with fatigue crack growing from radius to fastener hole

    D0 1

    6017

    Southwest Research Institute is an independent, nonprofit, applied engineering and physical sciences research and development organi-zation using multidisciplinary approaches to problem solving. The Institute occupies 1,200 acres in San Antonio, Texas, and provides more than 2 million square feet of laboratories, test facilities, work-shops and offices for more than 3,100 employees who perform contract work for industry and government clients.