- •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
MECHANICAL PROPERTY MEASUREMENT |
237 |
~ y L |
P / / r |
I. b |
.I |
r |
Vl |
Fig. 7.18 Mode HI edge crack torsion test (ECT).
7.5.1.5 Mode/11 Interlaminar Fracture Test. The measurement of mode
IIIinterlaminar fracture energy can be done based on the out-of-plane torsion of a cracked plate specimen,26 as shown in Figure 7.18. A series of edge-crack torsion (ECT) specimens with different initial crack lengths are prepared. These are loaded in torsion by pushing down on one comer. The compliance can be determined from the initial parts of the load-load point displacement plots:
1 = A [ 1 - m ( b ) ] |
(7.12) |
Plotting 1/C against a/b gives m. The strain energy release rate for mode III, Giiic, is then obtained from the expression:
mp2C Gmc = 2Lb(1 - m(a/b))
References
~Adams, D. F., "Test Methods for Mechanical Properties," Materials, edited by A. Kelly and C. Zweben, Elsevier, 2000.
2"Standard Test Method for Tensile Properties of Polymer Matrix Materials," ASTM Standard D3039/D3039M-95a.
3,,Standard Test Method for Open-Hole Properties of Unidirectional or Crossply Fibreresin Composites," ASTM D5766/D5766M-95.
4"Standard Test Method for Compressive Properties of Unidirectional or Crossply Fibre-resin Composites," ASTM Standard D3410/3410M-95
5,,Flexural Properties of Unreinforced and Reinforced Plastics and Electrical Insulating Material," ASTM Standard D790-84a.
6"Standard Guide for Testing In-Plane Shear Properties of Composite Iaminates," ASTM Guide D4255/D4255-83 (94).
7,,Standard Test Method for Shear Properties of Composite Materials by the V-Notched Beam Method," ASTM Standard D5379/D5379M-93.
8"Standard Test Method for In-Plane Shear Response of Polymer Matrix Composite Materials by Tensile Test of a __+45° Laminate," ASTM Standard D3518/D3518M-94.
9"Standard Test Method for Apparent Interlaminar Shear Strength of Parallel Fibre Composites by Short-Beam Method," ASTM Standard D2344-84.
238 COMPOSITE MATERIALS FOR AIRCRAFT STRUCTURES
~°"Compressive Properties of Oriented Fiber-Resin Composites," SACMA Recommended Test Method 1R-94.
11"Open Hole Compression Properties of Oriented Fiber-Resin Composites," SACMA Recommended Test Method 3R-94.
12Zweben, C., "Is There a Size Effect in Composites," Composites, Vol. 25, 199, p. 451. 13Chen, A. S., and Matthews, F. L., "A Review of Multiaxial/Biaxial Loading Tests for
Composite Materials," Composites, Vol. 24, 1993, p. 395.
~4Welsh, J. S., and Adams, D. F., "Current Status of Compression Test Methods for Composite Materials," SAMPE Journal, Vol. 33, 1997, p. 35.
15Componeschi, E. T., Jr, "Compression of Composite Materials: A Review,"
Composite Materials: Fatigue and Fracture, ASTM STP 1110, Vol. 3, p. 550. 16Ciriscioli, P. R., Lee, W. I., and Peterson, D. G., "Accelerated Environmental Testing
of Composites," Journal of Composite Materials, Vol. 21, 1987, pp. 225-242. 17Gerharz, J. J., "Standardised Environmental Fatigue Sequence for the Evaluation of
Composite Components in Combat Aircraft ENSTAFF = Environmental FalSTAFF," National Aerospace Laboratory NLR, The Netherlands, Report NLR TR 87053 U. Also published as LBF Report No. FB-179(1987), IABG Report a No. B-TF 2194 (1987), and RAE Report No. TR 87048
aSHorton, R. E., and McCartney, J. E., "Damage Tolerance of Composites," Composite Materials Analysis and Design, 1984, pp. 260-267
~9"Standard Tests for Toughened Resin Composites, Revised Edition," NASA Referenced Publication 1092--Revised 1983.
2°Gurney, C., and Hunt, J., "Quasi-Static Crack Propagation," Proceedings of the Royal Society of London, Vol. A299, 1967, pp. 508-524.
2~"Mode I Interlaminar Fracture Toughness of Unidirectional Fibre-Reinforced Polymer Matrix Composites," ASTM D5528, 1994.
220'Brien, T. K., and R. H. Martin, "Round Robin Testing for Mode I Interlaminar Fracture Toughness of Composite Materials," Journal of Composites Technology and Research, Vol. 15, 1993, pp. 269-281.
23Tanaka, K., Kageyama, K. and Hojo, M., "Prestandardization Study on Mode II Interlaminar Fracture Toughness Test for CFRP in Japan," Composites, Vol. 26, 1995, pp. 257-267.
24Russel, A. J., and Street, K. N., "Moisture and Temperature Effects on the Mixedmode Delamination Fracture of Unidirectional Carbon/Epoxy," Delamination and Debonding of Materials, ASTM STP 876, edited by W. S. Johnson, ASTM, Philadelphia, 1985, pp. 349-372.
25Brussat, T. R., Chiu, S. T., and Mostovoy, S., Fracture Mechanics for Structural Adhesive Bonds, AFML-TR-77-163, Air Force Materials Laboratory, Wright-Patterson AFB, Dayton, OH, 1997.
26Lee, S. M., "An Edge Crack Torsion Method for Mode III Delamination Fracture Testing," Journal of Composites Technology and Research, Vol. 15, 1993, pp. 193-201.