Damage Tolerance and Durability of Material Systems
"Damage is an abstraction . . . Strength is an observable, an independent variable that can be measured, with clear and familiar engineering definitions."
-from the Preface to Damage Tolerance and Durability of Material Systems
Long-term behavior is one of the most challenging and important aspects of material engineering. There is a great need for a useful conceptual or operational framework for measuring long-term behavior. As much a revolution in philosophy as an engineering text, Damage Tolerance and Durability of Material Systems postulates a new mechanistic philosophy and methodology for predicting the remaining strength and life of engineering material. This philosophy associates the local physical changes in material states and stress states caused by time-variable applied environments with global properties and performance.
There are three fundamental issues associated with the mechanical behavior of engineering materials and structures: their stiffness, strength, and life. Treating these issues from the standpoint of technical difficulty, time, and cost for characterization, and relationship to safety, reliability, liability, and economy, the authors explore such topics as:
* Damage tolerance and failure modes
* Factors that determine composite strength
* Micromechanical models of composite stiffness and strength
* Stiffness evolution
* Strength evolution during damage accumulation
* Non-uniform stress states
* Lifetime prediction
With a robust selection of example applications and case studies, this book takes a step toward the fulfillment of a vision of a future in which the prediction of physical properties from first principles will make possible the creation and application of new materials and material systems at a remarkable cost savings.
Introduction: Basic Thesis.
I.1 Elements of the Approach.
I.2 Basic Concepts.
I.3 Nonuniform Stress States: Characteristic Material Dimensions.
I.4 Strength Evolution.
I.5 Outline of the Methodology.
I.6 Virtual Design.
1 Physical Behavior.
1.1 Continuous-Fiber Composite Materials.
1.2 Damage Tolerance and Durability.
1.3 Damage Modes and Failure Modes.
1.4 Summary of Concepts.
2 Engineering Concepts of Strength.
2.1 Factors That Determine Composite Material Strength.
2.2 Strength under Multiaxial Loading.
2.3 Failure Functions for Damage Accumulation.
3 Strength Evolution.
3.1 Nature of the Problem.
3.2 Progressive Failure.
3.3 Failure Modes.
3.4 Remaining Strength under Long-Term Loading.
3.5 Features of Strength Evolution Integral.
3.6 Summary of Approach.
4 Micromechanical Models of Composite Stiffness and Strength.
4.1 Axial Tensile Strength of Unidirectional Composites.
4.2 Compression Strength.
4.3 Transverse Strength and Shear Strength.
5 Stiffness Evolution.
5.1 Problem Definition.
5.2 Stiffness Change Due to Matrix Cracking.
5.3 Time-Dependent Stiffness Change.
5.4 Temperature-Dependent Stiffness Change.
6 Strength Evolution During Damage Accumulation.
6.1 Problem Definition.
6.2 Factors That Influence Strength.
6.3 Models of Strength Evolution.
6.4 Application Example.
7 Nonuniform Stress States.
7.1 Problem Definition.
7.2 Laminate Edge-Related Stresses.
7.3 Undamaged Notched Strength.
7.4 Notched Strength After Damage.
7.5 Fracture Mechanics and Energy Methods.
8 Example Applications and Case Studies.
8.1 Example: Unnotched Failure of Polymer Composite.
8.2 Case Study 1: Fatigue Behavior of APC-2 Laminates.
8.3 Case Study 2: Elevated-Temperature Fatigue Behavior of Graphite Fiber-PPS Laminates.
8.4 Case Study 3: Elevated-Temperature Fatigue Behavior of Nextel 610.... Alumina-Yttria Composites.
8.5 Case Study 4: Elevated-Temperature Fatigue Behavior of Nicalon-Enhanced SiC Composites.
8.6 Case Study 5: Fatigue Failure of a Structural Composite Shape.
Appendix to Chapter 1.
"...a useful reference..." (AIAA Journal, Vol. 40, No. 10, October 2002)