Mechanical Behavior of Organic Matrix Composites

Mechanical Behavior of Organic Matrix Composites: Effect of Thermo-oxidative Ageing The book focuses on the effect of ageing (thermo-oxidation, humid ageing) on the mechanical properties of organic matrix composite materials, covering: Bibliographic issues and a detailed state-of-the-art; phenomenological and experimental issues; modelling issues and models parameter identification; illustration and interpretation of experimental tests and proposal for novel test design in the light of the model predictions.

List of Figures ix Acknowledgements xxi Preface xxiii Introduction xxvii Chapter 1 Phenomenological Aspects of Thermo-oxidative Ageing of OMCs 1 1.1 Effect of thermo-oxidation on the local mechanical behavior of the polymer 7 1.1.1 Oxidized layers 10 1.1.2 EIT measurements by UMI 14 1.1.3 Introduction to the parameter γ, an oxidation tracer 19 1.1.4 Characterizing the local mechanical behavior of the polymer 24 1.1.5 Oxidized material 33 1.2 Study of matrix shrinkage induced by thermo-oxidation in unidirectional OMCs 37 1.2.1 Virgin sample 40 1.2.2 Sample oxidized under 2 bar O2 47 1.2.3 Air-oxidized sample 53 Chapter 2 Modeling of Thermo-oxidative Ageing of OMCs 59 2.1 Thermodynamics of irreversible processes with internal variables 59 2.2 Development of an ageing-dependent behavior law for organic polymers 64 2.3 Taking into account the initial inelastic and chemical strains 77 Chapter 3 Identification and Simulations 79 3.1 Identifying the behavior law of thermo-oxidized polymers through the inverse analysis of ultra-micro-indentation tests 79 3.1.1 The method to identify the local mechanical behavior of virgin and oxidized polymers 79 3.1.2 Identification of local mechanical behavior of virgin polymers 83 3.1.3 Identifying the local mechanical behavior of the oxidized polymer 87 3.2 Identification of inelastic strains of chemical origin by inverse analysis of matrix shrinkage in unidirectional OMCs 93 3.2.1 Method for identifying inelastic strains in virgin and oxidized OMCs 96 3.2.2 Identification of inelastic strains and calculation of stresses in virgin OMCs 98 3.2.3 Identification of inelastic strains in oxidized OMCs 102 3.2.4 Validating the identification of inelastic strains of chemical origin 105 3.2.5 Numerical simulation of stresses induced by thermo-oxidation in UD OMCs 108 3.2.6 Rayleigh–Ritz approach for approximate computation of matrix shrinkage in OMCs 111 Conclusion and Perspectives 119 Bibliography 127 Index 133