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AE693A: Aircraft Structural Integrity

Course Description


This is an application-oriented course to impart basic and essential aspects of engineering knowledge required for assessing and ensuring safety of aircraft structures over entire lifetime. Both metallic and composite structures would be addressed. Design philosophies of safe-life, fail-safe and damage-tolerant design will be addressed. This would involve elements of various subjects, such as, mechanics of materials, fatigue and corrosion of metals, fracture mechanics, and damage behavior of composites as well as elementary statistics. 


Course Content

COURSE CONTENT: (Hours allocation is tentative):

  1. Introduction to Aircraft Structural Integrity (3 hrs) : Basic concepts and Historical evolution )
  2. Basics of Fatigue (6 hrs): Stress-Life curves;  HCF and LCF, Constant amplitude and Variable Amplitude loading, Effect of Mean Stress, Stress Concentration and Notches, strain-life approach, Cumulative damage and Miner Rule, Fatigue Load spectra and Life estimation.
  3. Elements of Fracture Mechanics (11 hrs) : Energy approach and Linear Elastic Fracture Mechanics, Effect of Plasticity, Fracture Mechanical Parameters and their relationships, thickness effect; Testing for Fracture mechanics parameters; Crack growth under fatigue loading, Paris and other Laws, Crack closure effect, fatigue life estimation; Damage tolerance analysis and inspection intervals. NDT techniques and probability of detection
  4. Composite Material and structures (11 hrs) : Introduction to laminated composites in aircraft; nature of composite behaviour; General concerns with composites; constitutive behaviour; strength behaviour, Hygrothermal effect; Designing with Composites: lay‐up considerations; Holes, Fastener Joints and Bearing Stresses; Impact Damage: Compression after Impact and BVID Concept, Fatigue Considerations.  
  5. Miscellaneous issues (8 hrs): Statistical aspects in accounting for scatter and variability; Corrosion, lightning strike, Review of Design Philosophies, ASIP, Certification issues and Strategies. Structural Health Monitoring Concept.

Course Audience

PG (Aero) Students

Final year B Tech (Aero) Students 

Outcomes of this Course

Knowledge and skills regarding

  • Lifing of aircraft.
  • Damage tolerant Design of aircraft structures
  • Assessment and assurance of safety of aircraft structures