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