Page 7 - Plastics Engineering

vi Contents

Chapter 2 - Mechanical Behaviour of Plastics 41
2.1 Introduction 41
2.2 Viscoelastic Behaviour of Plastics 42
2.3 Short-Term Testing of Plastics 43
2.4 Long-Term Testing of Plastics 45
2.5 Design Methods for Plastics using Deformation Data 48
2.6 Thermal Stresses and Strains 61
2.7 Multi-layer Mouldings 66
2.8 Design of Snap Fits 71
2.9 Design of Ribbed Sections 74
2.10 Stiffening Mechanisms in Other Moulding Situations 81
2.1 1 Mathematical Models of Viscoelastic Behaviour 84
2.12 Intermittent Loading 95
2.12.1 Superposition Principle 95
2.12.2 Empirical Approach 103
2.13 Dynamic Loading of Plastics 110
2.14 Time-Temperature Superposition 116
2.15 Fracture Behaviour of Unreinforced Plastics 119
2.16 The Concept of Stress Concentration 121
2.17 Energy Approach to Fracture 121
2.18 Stress Intensity Factor Approach to Fracture 127
2.19 General Fracture Behaviour of Plastics 131
2.20 Creep Failure of Plastics 134
2.20.1 Fracture Mechanics Approach to Creep Fracture 136
2.20.2 Crazing in Plastics 137
2.21 Fatigue of Plastics 138
2.21.1 Effect of Cyclic Frequency 140
2.21.2 Effect of Waveform 142
2.21.3 Effect of Testing Control Mode 142
2.2 1.4 Effect of Mean Stress 143
2.21.5 Effect of Stress System 145
2.21.6 Fracture Mechanics Approach to Fatigue 145
2.22 Impact Behaviour of Plastics 147
2.22.1 Effect of Stress Concentrations 148
2.22.2 Effect of Temperature 150
2.22.3 Miscellaneous Factors Affecting Impact 152
2.22.4 Impact Test Methods 152
2.22.5 Fracture Mechanics Approach to Impact 154

Chapter 3 - Mechanical Behaviour of Composites 168
3.1 Deformation Behaviour of Reinforced Plastics 168
3.2 Types of Reinforcement 168