- •Foreword
- •Foreword to First Edition
- •Contributors
- •Preface
- •A.1 Piezoelectric Materials
- •A.3 Optical Fiber Sensors
- •A.4 Electrorheological Fluids
- •A.5 Magnetostrictive Materials
- •A.6 Micro-Electro-Mechanical Systems
- •A.7 Comparison Of Actuators
- •References
- •Index
- •1. Introduction and Overview
- •1.1 General
- •1.3 High-Performance Fiber Composite Concepts
- •1.4 Fiber Reinforcements
- •1.5 Matrices
- •References
- •Bibliography
- •2. Basic Principles of Fiber Composite Materials
- •2.1 Introduction to Fiber Composite Systems
- •2.3 Micromechanics
- •2.4 Elastic Constants
- •2.5 Micromechanics Approach to Strength
- •2.6 Simple Estimate of Compressive Strength
- •References
- •3. Fibers for Polymer-Matrix Composites
- •3.1 Overview
- •3.3 Carbon Fibers
- •3.4 Boron Fibers
- •3.5 Silicon Carbide
- •3.6 Aramid Fibers
- •3.7 Orientated Polyethylene Fibers
- •3.8 Dry Fiber Forms
- •References
- •4. Polymeric Matrix Materials
- •4.1 Introduction
- •4.2 Thermoset and Thermoplastic Polymer Matrix Materials
- •4.3 Thermosetting Resin Systems
- •4.4 Thermoplastic Systems
- •References
- •5. Component Form and Manufacture
- •5.1 Introduction
- •5.2 Outline of General Laminating Procedures
- •5.5 Filament Winding
- •5.7 Process Modelling
- •5.8 Tooling
- •References
- •6. Structural Analysis
- •6.1 Overview
- •6.2 Laminate Theory
- •6.3 Stress Concentration and Edge Effects
- •6.4 Failure Theories
- •6.7 Buckling
- •6.8 Summary
- •References
- •7. Mechanical Property Measurement
- •7.1 Introduction
- •7.2 Coupon Tests
- •7.3 Laboratory Simulation of Environmental Effects
- •7.4 Measurement of Residual Strength
- •7.5 Measurement of Interlaminar Fracture Energy
- •References
- •8. Properties of Composite Systems
- •8.1 Introduction
- •8.3 Boron Fiber Composite Systems
- •8.4 Aramid Fiber Composite Systems
- •8.6 Properties of Laminates
- •References
- •9. Joining of Composite Structures
- •9.1 Introduction
- •9.2 Comparison Between Mechanically Fastened and Adhesively Bonded Joints
- •9.3 Adhesively Bonded Joints
- •9.4 Mechanically Fastened Joints
- •References
- •10. Repair Technology
- •10.1 Introduction
- •10.2 Assessment of the Need to Repair
- •10.3 Classification of Types of Structure
- •10.4 Repair Requirements
- •10.6 Patch Repairs: General Considerations
- •10.7 Bonded Patch Repairs
- •10.9 Application Technology: In Situ Repairs
- •10.10 Bolted Repairs
- •References
- •11. Quality Assurance
- •11.1 Introduction
- •11.2 Quality Control
- •11.3 Cure Monitoring
- •References
- •12. Aircraft Applications and Design Issues
- •12.1 Overview
- •12.2 Applications of Glass-Fiber Composites
- •12.3 Current Applications
- •12.4 Design Considerations
- •12.7 A Value Engineering Approach to the Use of Composite Materials
- •12.8 Conclusion
- •References
- •13. Airworthiness Considerations For Airframe Structures
- •13.1 Overview
- •13.2 Certification of Airframe Structures
- •13.3 The Development of Design Allowables
- •13.4 Demonstration of Static Strength
- •13.5 Demonstration of Fatigue Strength
- •13.6 Demonstration of Damage Tolerance
- •13.7 Assessment of the Impact Damage Threat
- •References
- •14. Three-Dimensionally Reinforced Preforms and Composites
- •14.1 Introduction
- •14.2 Stitching
- •14.3 Z-Pinning
- •14.6 Knitting
- •14.8 Conclusion
- •References
- •15. Smart Structures
- •15.1 Introduction
- •15.2 Engineering Approaches
- •15.3 Selected Applications and Demonstrators
- •References
- •16. Knowledge-Based Engineering, Computer-Aided Design, and Finite Element Analysis
- •16.2 Finite Element Modelling of Composite Structures
- •16.3 Finite Element Solution Process
- •16.4 Element Types
- •16.5 Finite Element Modelling of Composite Structures
- •16.6 Implementation
- •References
112 COMPOSITE MATERIALS FOR AIRCRAFT STRUCTURES
4.4.6 Polyetherimide
Polyetherimide (PEI) is an amorphous, high-performance thermoplastic. The amorphous structure of PEI contributes to its dimensional stability, low shrinkage, and highly isotropic mechanical properties compared with most crystalline polymers. The high Tg allows PEI to be used intermittently at 200 °C. Un-reinforced PEI is one of the strongest engineering amorphous thermoplastics and offers very good mechanical properties but has the forming disadvantage of very high viscosity in the molten state. Despite being amorphous, PEI is very tolerant to solvents and environmental exposure and resists a broad range of chemicals, including most hydrocarbons, non-aromatic alcohols, and fully halogenated solvents. The molecular structure of some of the polyimide resins is depicted in Figure 4.20.
References
1Kumar, A., and Gupta, R. K., Fundamentals of Polymers, McGraw-Hill, New York, 1998.
2Chawla, K. K., Composite Materials Science and Engineering, Springer-Verlag; New York, 1987.
3Niu, M. C., Composite Airframe Structures, "Materials," Conmilit Press, Hong Kong, Chapter 2, 1992.
4Muzzy, J. D., "Thermoplastics Properties," Comprehensive Composite Materials, edited by A. Kelly and C. Zweben, Vol. 2, Elsevier, Cambridge, 2000.
5Brandrup, J., Immergut, E. H., and Grulke, E. A., Polymer Handbook, 4, John Wiley & Sons, New York, 1999.
6Varma, I. K., and Gupta, V. B., "Thermosetting Resin Properties," Comprehensive Composite Materials, edited by A. Kelly, C. Zweben, Vol. 2, Elsevier, Cambridge, 2000.
7Green, G. E., "Matrices for Advanced Structural Composites," Composite Materials in Aircraft Structures, edited by D. H. Middleton, Longmans, UK, 1997, Chapter 4.
8May, C. A. (ed.), Epoxy Resins, Chemistry and Technology, 2nd ed., Marcel Dekker, New York, 1988.
9Gillham, J. K., "The Formation and Properties of Network Polymeric Materials,"
Polymer Engineering & Science, Vol. 19, 1979, pp. 676-682.
l°Bascum, W. D., and Hunston, D. L., "The Fracture of Epoxy and Elastomer-Modified Epoxy Polymers," Treatise on Adhesion and Adhesives, Vol. 6, edited by R. L. Patrick, Marcel Dekker, New York, 1989, Chapter 4.
11Reinhart, T. J., (ed.), Composite Engineered Materials Handbook, Vol. 1, American Society for Metals International, 1993, pp. 100-101.