Mechanical Behavior of Organic Matrix Composites: Effect of Thermo-oxidative Ageing

Table of Contents

Cover

Title

Copyright

List of Figures

Acknowledgements

Preface

Introduction

1 Phenomenological Aspects of Thermo-oxidative Ageing of OMCs

1.1. Effect of thermo-oxidation on the local mechanical behavior of the polymer

1.2. Study of matrix shrinkage induced by thermo-oxidation in unidirectional OMCs

2 Modeling of Thermo-oxidative Ageing of OMCs

2.1. Thermodynamics of irreversible processes with internal variables

2.2. Development of an ageing-dependent behavior law for organic polymers

2.3. Taking into account the initial inelastic and chemical strains

3 Identification and Simulations

3.1. Identifying the behavior law of thermo-oxidized polymers through the inverse analysis of ultra-micro-indentation tests

3.2. Identification of inelastic strains of chemical origin by inverse analysis of matrix shrinkage in unidirectional OMCs

Conclusion and Perspectives

Bibliography

Index

End User License Agreement

List of Tables

1 Phenomenological Aspects of Thermo-oxidative Ageing of OMCs

Table 1.1. Characteristic times τ1 and τ2 according to the partial pressure of oxygen (see also [GIG 16a, MIN 13, MIN 14])

Table 1.2. Local fiber volume fraction in zones A, B, C and D and the nominal value of the plate (see also [GIG 16b, GIG 16c])

2 Modeling of Thermo-oxidative Ageing of OMCs

Table 2.1. Values of the parameters of the evolutive law of γ for ageing in air at atmospheric pressure or under 2 bar O2. (see also [GIG 16a, MIN 13, MIN 14])

3 Identification and Simulations

Table 3.1. Parameters identified for the local behavior law of the virgin TACTIX polymer (see also [GIG 16a, MIN 13, MIN 14])

Table 3.2. Total inelastic strains identified by the Rayleigh–Ritz method and by the FE model (see also [GIG 16b, GIG 16c])

List of Illustrations

Introduction

Figure I.1. Observation by interferometric microscopy (IM) of the surfaces of aged UD samples. For a color version of this figure, see www.iste.co.uk/gigliotti/mechanical.zip

Figure I.2. The principle of IM. For a color version of this figure, see www.iste.co.uk/gigliotti/mechanical.zip

Figure I.3. 3D reconstruction of the surface (25 × 25 μm) of UD samples (virgin and aged) observed by IM (see also [GIG 16b, GIG 16c]). For a color version of this figure, see www.iste.co.uk/gigliotti/mechanical.zip

1 Phenomenological Aspects of Thermo-oxidative Ageing of OMCs

Figure 1.1. COMEDI test setup for material ageing (see also [GIG 16a, MIN 13, MIN 14]). For a color version of this figure, see www.iste.co.uk/gigliotti/mechanical.zip

Figure 1.2. Color change of TACTIX resin samples induced by thermo-oxidation (see also [GIG 16a, MIN 13, MIN 14]). For a color version of this figure, see www.iste.co.uk/gigliotti/mechanical.zip

Figure 1.3. Change in mass of TACTIX resin samples aged in air at atmospheric pressure and under 2 bar O2 at a temperature of 150°C (see also [GIG 16a, MIN 13, MIN 14]). For a color version of this figure, see www.iste.co.uk/gigliotti/mechanical.zip

Figure 1.4. DMA spectra of the TACTIX resin in the initial state: a) conservation modulus E′ and b) loss modulus E″ (see also [GIG 16a, MIN 13, MIN 14])

Figure 1.5. DMA spectra of TACTIX resin samples oxidized at 150°C under 2 bar O2 for different durations of up to 5 days of ageing: a) conservation modulus and b) loss modulus (see also [GIG 16a, MIN 13, MIN 14]). For a color version of this figure, see www.iste.co.uk/gigliotti/mechanical.zip

Figure 1.6. Schematic representation of ultra-micro-indentation (UMI) tests. For a color version of this figure, see www.iste.co.uk/gigliotti/mechanical.zip

Figure 1.7. Protocol for preparing samples for UMI tests (see also [GIG 16a, MIN 13, MIN 14]). For a color version of this figure, see www.iste.co.uk/gigliotti/mechanical.zip

Figure 1.8. a) Fischerscope® H100C for ultra-micro-indentation (UMI) tests; b) schematic of a load-indentation depth curve by UMI (see also [GIG 16a, MIN 13, MIN 14]). For a color version of this figure, see www.iste.co.uk/gigliotti/mechanical.zip

Figure 1.9. Images by optical microscopy (OM) of indentation surfaces of four TACTIX resin samples oxidized at 150°C under 2 bar O2: a) 24 hours; b) 48 hours; c) 72 hours and d) 120 hours (see also [GIG 16a, MIN 13, MIN 14])

Figure 1.10. a) Image using OM and b) IM of the indentation surface of a TACTIX resin sample oxidized for 24 hours at 150°C under 2 bar O2 (see also [GIG 16a, MIN 13, MIN 14]). For a color version of this figure, see www.iste.co.uk/gigliotti/mechanical.zip

Figure 1.11. Images using IM of indentation surfaces of TACTIX resin samples: a) in the initial state and for four oxidized samples; b) at 24 hours; c) at 48 hours; d) at 72 hours and e) at 120 hours at 150°C under 2 bar O2 (see also [GIG 16a, MIN 13, MIN 14]). For a color version of this figure, see www.iste.co.uk/gigliotti/mechanical.zip

Figure 1.12. Vertical displacements as a function of distance from the surface exposed to the environment using IM on indentation surfaces of TACTIX resin samples: in the initial state and for four oxidized samples, 24 hours, 48 hours, 72 hours and 120 hours at 150°C under 2 bar O2 (see also [GIG 16a, MIN 13, MIN 14]). For a color version of this figure, see www.iste.co.uk/gigliotti/mechanical.zip

Figure 1.13. EIT measurements for TACTIX resin: a) virgin and b) after 48 hours remaining in a neutral environment, 2 bar N2, at 150°C (see also [GIG 16a, MIN 13, MIN 14])

Figure 1.14. Profiles of the EIT modulus, for TACTIX resin: a) after ageing in air and b) under 2 bar O2, at 150°C (see also [GIG 16a, MIN 13, MIN 14]). For a color version of this figure, see www.iste.co.uk/gigliotti/mechanical.zip

Figure 1.15. Variation: a) in the EIT modulus and b) in the thickness of the oxidized layers as a function of the ageing time at 150°C under 2 bar O2 (TACTIX resin) (see also [GIG 16a, MIN 13, MIN 14])

Figure 1.16. EIT profiles obtained for TACTIX resin aged under 2 bar O2 at 150°C (120 hours) superimposed on OM images of oxidized surfaces (see also [GIG 16a, MIN 13, MIN 14])

Figure 1.17. Comparison of EIT modulus profiles, for TACTIX resin, after ageing at 150°C for 24 hours under 2 bar O2 (red curve) and 200 hours in air at atmospheric pressure (blue curve) (see also [GIG 16a, MIN 13, MIN 14]). For a color version of this figure, see www.iste.co.uk/gigliotti/mechanical.zip

Figure 1.18. Profiles of the parameter γ obtained for the TACTIX resin aged at 150°C: a) in air at atmospheric pressure and b) under 2 bar O2 (see also [GIG 16a, MIN 13, MIN 14]). For a color version of this figure, see www.iste.co.uk/gigliotti/mechanical.zip

Figure 1.19. Value of γ (γmax), measured at 40 μm from the external edge as a function of the oxidation duration, for the TACTIX resin aged at 150°C in air at atmospheric pressure or under 2 bar O2 (see also [GIG 16a, MIN 13, MIN 14]). For a color version of this figure, see www.iste.co.uk/gigliotti/mechanical.zip

Figure 1.20. Ageing master curve, visualizing the evolution of γmax as a function of the reduced time t* (T = 150°C, pref. = patm.) (see also [GIG 16a, MIN 13, MIN 14]). For a color version of this figure, see www.iste.co.uk/gigliotti/mechanical.zip

Figure 1.21. a) Profiles of γ as a function of the distance from the edge and the oxidation time for the TACTIX resin aged under 2 bar of O2 at 150°C. b) Comparison of indentation curves corresponding to two values of γ: 0.1 and 0.5 (see also [GIG 16a, MIN 13, MIN 14]). For a color version of this figure, see www.iste.co.uk/gigliotti/mechanical.zip

Figure 1.22. a) Profiles of γ as a function of the distance from the edge of the TACTIX resin samples aged at 150°C, 200 hours in air at atmospheric pressure and 24 hours under 2 bar O2. b) Comparison of indentation curves corresponding to two values of γ: 0.1 and 0.5 (see also [GIG 16a, MIN 13, MIN 14]). For a color version of this figure, see www.iste.co.uk/gigliotti/mechanical.zip

Figure 1.23. Experimental technique based on the joint use of UMI to measure load versus indentation depth curves and IM to monitor the relaxation of the indentation print after unloading (see also [GIG 16a, MIN 13, MIN 14]). For a color version of this figure, see www.iste.co.uk/gigliotti/mechanical.zip

Figure 1.24. Load versus indentation depth curve obtained by UMI on virgin TACTIX resin: 15 indentation curves are superimposed (see also [GIG 16a, MIN 13, MIN 14])

Figure 1.25. Load versus indentation depth curve obtained by UMI on virgin TACTIX resin: effect of loading speed (see also [GIG 16a, MIN 13, MIN 14]). For a color version of this figure, see www.iste.co.uk/gigliotti/mechanical.zip

Figure 1.26. Load versus indentation depth curve obtained by UMI on virgin TACTIX resin: effect of creep phase (see also [GIG 16a, MIN 13, MIN 14]). For a color version of this figure, see www.iste.co.uk/gigliotti/mechanical.zip

Figure 1.27. Load imposed during a progressive indentation test (see also [GIG 16a, MIN 13, MIN 14])

Figure 1.28. Comparison of a progressive indentation test (red curve) with that of a monotonous test (grey curve) (see also [GIG 16a, MIN 13, MIN 14]). For a color version of this figure, see www.iste.co.uk/gigliotti/mechanical.zip

Figure 1.29. Evolution of the EIT modulus during a progressive indentation test. Virgin TACTIX sample (see also [GIG 16a, MIN 13, MIN 14]). For a color version of this figure, see www.iste.co.uk/gigliotti/mechanical.zip

Figure 1.30. Images by IM of an indentation curve on the surface of a virgin sample: a) 10 minutes; b) 5 days; c) 3 months after indentation test and d) evolution of a profile over time (see also [GIG 16a, MIN 13, MIN 14]). For a color version of this figure, see www.iste.co.uk/gigliotti/mechanical.zip

Figure 1.31. Recovery of indentation curve after a UMI test: virgin TACTIX sample (see also [GIG 16a, MIN 13, MIN 14])

Figure 1.32. Indentation curves at different distances from the edge of the oxidized sample for 120 hours at 150°C under 2 bar O2 (see also [GIG 16a, MIN 13, MIN 14]). For a color version of this figure, see www.iste.co.uk/gigliotti/mechanical.zip

Figure 1.33. Indentation curves at 20 μm from the edge of the sample. Black curve: virgin sample. Curves with symbols: samples oxidized at 150°C under 2 bar O2 for 24 hours (circles), 72 hours (triangles) and 120 hours (squares) (see also [GIG 16a, MIN 13, MIN 14]). For a color version of this figure, see www.iste.co.uk/gigliotti/mechanical.zip

Figure 1.34. Comparison of profiles of indentation curves measured on a virgin sample (black curve) and at 20 μm from the edge of a sample oxidized for 72 hours at 150°C under 2 bar O2 (red curve) (see also [GIG 16a, MIN 13, MIN 14]). For a color version of this figure, see www.iste.co.uk/gigliotti/mechanical.zip

Figure 1.35. Comparison between the recovery curve of a virgin sample (in black) and that obtained from a sample oxidized for 72 hours under