Composite Structures, Design, Safety and Innovation


  • Dr. Bjorn Backman, Structure and Materials Structured Research, Camano Island, WA, USA

Aerospace structural design, especially for large aircraft, is an empirical pursuit dominated by rules of thumb and often-painful service experiences. Expertise on traditional materials is not transferable to “new” materials, processes and structural concepts. This is because it is not based on or derived from well-defined measures of safety. This book addresses the need for safe innovation based on practical, explicit structural safety constraints for use in innovative structures of the future where guiding service experience is non-existent. The book covers new ground by the demonstration of ways to satisfy levels of safety by focusing on structural integrity; and complementing the lack of service experience with risk management, based on flexible inspection methods recognizing that safety is a function of time. Fundamentally the book shoes demonstrates how safety methods can be made available to the engineering community without requiring huge statistical databases to establish internal and external loads distributions for use in reliability analysis.An essential title for anyone working on structural integrity, or composite structures. It will be of equal interest to aerospace engineers and materials scientists working in academia, industry and government.
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Academia: Aeronautical and Aerospace Engineering Depts, and Materials Science and Engineering Departments.Industry: Practicing Engineers and Scientists in Structures, Materials Science, Airworthiness, Safety, Quality Control, for testing, design, development and applied researchGovernment: Practising engineers and Scientists at NASA, DOD, DARPA, NTSB,…. For research and development of improved safety, (of space shuttles), Innovative structural concepts, better materials, “Crisper” regulations for safety.


Book information

  • Published: June 2005
  • Imprint: ELSEVIER
  • ISBN: 978-0-08-044545-8


"The book should be read by all involved in the design of aerospace structures" - International Journal of Fatigue, John Summerscales, Advanced Composite Manufacturing Centre, University of Plymouth

Table of Contents

1.0 Introduction1.1 Traditional Design in Aerospace 1.2 Conventional Safety in Aerospace 1.3 Trends of Innovation in Aerospace Structures 1.4 Composites
2.0 Structural Design2.1 Damage Tolerance2.2 Structural Integrity2.3 Explicit Design Constraints2.4 Uncertainty in Design2.5 The Extended Design Process
3.0 Structural Safety3.1 Primary Drivers3.2 Risk Management3.3 Importance of Safety Regulations3.4 Uncertainty, Probability and Statistics of Damage Tolerance
4.0 Innovation4.1 Service Experience4.2 Criticality4.3 Damage Tolerance4.4 Inductive Methods
5.0 Safety Objectives5.1 Safety as a Function of Time5.2 Inspection5.3 Accidental Damage5.4 Design Data and Allowables
6.0 Risk Management6.1 Unsafe State6.2 Role of Inspections6.3 Functions of Time and Inspection Approach6.4 Uncertainty
7.0 Trades7.1 Impact7.2 Degradation7.3 Damage Undetected at Major Inspections7.4 Repair
8.0 Building Block Approach8.1 Components and Scale-up8.2 Allowables8.3 Criticality8.4 Current Practices8.5 Factor of Safety
9.0 Design Scenarios9.1 Damaged Metal Structure9.2 Damaged Composite Structure9.3 Damage Criteria9.4 Structural Allowables9.5 Limit Load Requirements 9.6 “New” Structural Concepts
10.0 The Design Process10.1 Ultimate Static Strength Critical Structure10.2 Damage Growth and Damage Resistance10.3 Damage Tolerance10.4 Discrete Source Damage10.5 Design Variables10.6 Criteria Damage10.7 Critical Damage Type
11.0 Damage and Detection11.1 Failed Detection11.2 Manufacturing Damage11.3 Maintenance Damage11.4 Accidental Damage11.5 Process Failure, Degradation and Damage11.6 In-Service Degradation and Damage11.7 Growth and Damage11.8 Ultimate Strength and Damage11.9 Safety and Damage
12.0 Design Philosophy12.1 Ultimate Strength Critical Design12.2 Damage and Residual Strength12.3 Allowables and Design Values12.4 Ultimate Strength Design Values12.5 Design Philosophy and Uncertainty12.6 Unsafe State and Design12.7 Ultimate Integrity and Design12.8 Survival Philosophy
13.0 Analysis of Design Criteria13.1 Vehicle Objective13.2 Overall Structural Objective13.3 Principal Structural Element Criteria13.4 Ultimate Requirement13.5 Damage Tolerance Requirement13.6 Inspection Criteria13.7 Damage Growth Rates Criteria13.8 Threat and Damage Criteria13.9 Safety Criteria Baseline13.10 Scale-up Criteria13.11 Failure Criteria13.12 Monitoring and Feedback Criteria13.13 Criteria for Safe Design of Damaged Structure
14.0 Design Example14.1 Geometrically Nonlinear Structural Design14.2 Fail-safety, Material Nonlinearities and Hybrid Design14.3 Fail-safe Criteria in Design14.4 Structural Concepts and Design Space14.5 Critical Damage Tolerance Design 14.6 Types of Data for Design
15.0 Design of Composite Structure
Appendix A A Model of Ultimate IntegrityAppendix B A Comparison between Metal and Composite Panels