Table of Contents

Each chapter ends with a Discussion and Conclusion section and a References section. I. Background 1. Introduction to Composite Materials Introduction - Classifications - Properties - Problems of Stress Concentration - Current Applications - Stress-Strain Relations - Laminated Plate Theory 2. Test Methods Introduction - Tension Tests - Compression Tests - Shear Tests - Tests of Open Hole Specimens - Methods for Damage Detection 3. Failure Criteria Introduction - Guidelines - Classical Failure Criteria - Discussions - New Failure Criteria - Failure Criteria in the Presence of Stress Gradient - Appendix: Transformation of Principal Stresses II. Finite-Width Solutions 4. Finite-Width Correction Factor for Anisotropic Plate Introduction - Fundamental Theory - Improved Theory - Experimental and Numerical Comparisons - Anisotropic Plate with an Elliptical Opening 5. Strain and Stress Concentrations Introduction - Stresses and Displacement Fields - Definition of Stress and Strain Concentration Factors - Anisotropic Plate with Circular Hole - Correction Factor for Finite-Width - Experimental Procedure - Experimental Results - SCF( and SCF( for Damaged Laminates - Appendix: Parametric Studies III. Laminate Failure Models (Analytical) 6. Approximate Stress Analyses and Stress Failure Models Introduction - Stress Analysis - Numerical Examples and Comparisons - Stress Failure Models - Applications 7. Experiment and Modified Failure Models Introduction - Experiment for Tensile Tests - Results for Data Reduction - Prediction for Modified Models - Results of the Modified Models IV. Lamina Failure Models (Analytical) 8. Point Strength and Minimum Strength Models Introduction - Stress Analysis - Strength Models - Crack Simulation - Experimental Observation - Predictions and Comparisons - Characteristic Length as a Function of Opening Construction 9. Lamina-Based Fiber Failure Criteria and Effective Stress Failure Models Introduction - Fracture Models - Unnotched Ultimate Strength - Results for Laminates with an Elliptical Opening - Baseline Characteristic Length - Comparison of Compression with Tension - Fracture Toughness 10. Notched Strength of Thermoplastic Composites Introduction - Strength Models - Finite-Width Correction Factor - Experimental Investigation - Comparison of Data - Results 11. Shear Loading of Composites Containing an Opening Introduction - Stress Analysis - Minimum Strength Model - Examples of Stress Distribution - Experimental Program - Comparisons 12. Multiaxial Loading of Multidirectional Laminates Introduction - Stress Distribution - Failure Criteria, Mechanisms and Models - Unnotched Ultimate Strength - Uniaxial Loading of Laminates with a Slanted Crack - Fracture Under Multiaxial Loading 13. Mixed-Mode Fracture of Unidirectional and Off-Axis Laminates Tensile Loading - Introduction - Stress Analysis - Complex Roots - Failure Models - Finite-Width Correction Factors - Experiment and Results - Correlation of Theory with Experiment 14. Mixed-Mode Fracture of Unidirectional and Off-Axis Laminates Compressive Loading - Introduction - Strength Analysis - Strength Models - Finite-Width Correction Factors - Experimental - Discussion and Conclusion 15. Correlation of Damage Mechanisms and Characteristic Lengths Introduction - Theoretical Background - Experimental Procedures - Results and Discussion - Comparison of Ultimate Strength Progressive Failure Models (Numerical) 16. A Progressive Failure Model for Laminates with Cutouts Introduction - Finite Element Analysis - Damaged Lamina Formulation - Failure Criteria - Computation Procedures - Parametric Studies - Comparison with Experiment 17. Damage Accumulation, and Accumulation due to Compressive Loading Introduction - Formulation of the Damage Problem - Finite Element Analysis - Damaged Lamina Formulation - Failure Criteria - Computation Procedures - Parametric Studies - Results - Limitations of the Model VI. Design Methodology 18. Design of Composite Laminates by a Ranking Method Introduction - Design Considerations and Objective - Stress and Strength Analysis - Design Methodology using Strength - Development of Computer Program RANKHO - Varying Thickness Ratios of Laminates - Laminates Generated by Rigid-Body Rotation - Designing Laminates with a Crack - Discussion and Conclusions 19. Optimal Design with an Iterative Method Introduction - Statement of the Problem - Design Methodology - Strength Ratio - Allowable Stress - Iterative Method - Results of the Iterative Method 20. Mechanical Response and Design of Laminates with a Reinforcement Introduction - Stress Analysis - Strength Models - Theoretical Results and Predictions - Design Methodology Appendix: Unit Conversion Tables - Index - 80 tables, 277 figures Illustrations The numerous schematics and X-ray radiographs in this volume illustrate stress concentrations, materials design and test methods. Here is a small sampling of this illustrative material: - An example of stress concentration problems in a typical wing structure for composite airplane - Deformations of a composite ply subjected to extensional and bending loads - A typical specimen for tension test - Schematic diagram of minisandwich specimen - Anti-buckling device for compression test of off-axis specimens - Methods of evaluating the stress interaction coefficient by Tsai and Wu - A finite-width anisotropic laminate containing a central elliptical opening - Measuring the strain concentration factor of anisotropic plates - The coordinates and characteristic length of a composite laminate with an opening - Compression-failed specimens of the AS4/APC-2 layup containing a hole - The distribution of tangential stress in a graphite/epoxy AS4/3502 laminate with a crack under shear loading - A three-rail shear specimen in testing fixture - Failed specimen of a graphite/PEEK AS4/APC-2 laminate containing a slanted 45o crack Reference Data More than 100 tables and graphs provide reference data on stress concentrations and failure. Here is a small sampling: - Elastic properties and specific gravity of typical isotropic and unidirectional composites - Ratios of specific tensile strength of typical materials and steel - Elastic properties of typical graphite/epoxy laminae - Predicted and experimental effective laminate properties - Data for Gr/Ep AS4/3502 laminates containing a circular hole - Strength properties - Ultimate strength of AS4/APC-2 laminates containing a central hole - Comparison of the experimental shear modulus and the prediction using laminated plate theory - Experimental results for the ultimate shear strength of Gr/Ep AS4/3502 laminates containing cracks - Comparison of the predicted and experimental notched strength for laminates containing a central hole - The top 15 laminates for the Stress Vector (0, 2, 0)

About the Author

Seng C. Tan