Mechanical behaviour and lifetime modelling of self-healing ceramic-matrix composites subjected to thermomechanical loading in air

Cluzel, Christophe; Baranger, Emmanuel; Ladevèze, Pierre; Mouret, Anne

doi:10.1016/j.compositesa.2008.10.020

Cited by 53 publications

(45 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In order to have a complete overview of the mechanisms and their competitions, a model able to handle all the competitions is necessary. The framework of the proposed model [11] is depicted in Figure 17 3. the high concentration of oxygen attacks the fibers; 4. matrix layers react with oxygen and form a glass; 5. oxygen diffuses slowly through the glass; 6. the low concentration of oxygen attacks slowly the fiber; 7. the boron carbide layer oxidation decreases the glass plug efficiency; 8. the oxidation under stress of some fibers reduces the threshold of brittle yarns; 9. mechanical loading may lead to yarn breakage and leads to the failure of the composite.…”

Section: Multiscale Modeling Of the Oxidation/damage Coupling And Thementioning

confidence: 99%

“…can penetrate the crack network and damage the fibers through oxidation or corrosion [67,68]. There have been attempts to introduce an environmental protection of the fibers within the composite (using, for example, self-healing multilayered ceramic matrices or fiber treatments, referred to as chemical fuses), but even then the environmental protection is not complete and the fibers remain one of the key factors in the material's lifetime [11,69]. The study of a fiber's lifetime under given environmental conditions is denoted static fatigue analysis because most works use the Paris law as in classical fatigue analysis, or subcritical cracking.…”

Section: Modeling Of the Subcritical Cracking Of Fibersmentioning

confidence: 99%

“…The idea, here, is to develop micro-multiphysic models that provide information for the computational macromodel. In fact the last version is very suitable for that [11,12]. The various experimental results obtained by SAFRAN Snecma Propulsion Solide or by Reference 13 were used to identify the mechanical model.…”

mentioning

confidence: 99%

See 2 more Smart Citations

Damage and Lifetime Modeling for Structure Computations

Baranger

Genet

Cluzel

2014

Ceramic Matrix Composites

View full text Add to dashboard Cite

INTRODUCTIONCeramic matrix composites (SiC fibers, PyC interphase, and mutistacked Si-B-C matrix in this paper) combine good mechanical properties with the capability of sustaining high temperatures in oxidizing environments. The use of a multilayer self-healing matrix improves the lifetime of ceramic matrix composites (CMCs) considerably [1]. This technology along with the use of SiC fibers paves the way for applications with very long lifetimes (several thousands of hours).Structural applications of CMCs need to answer to the main and critical question that is at the center of this chapter: how to predict, that is, to compute, the lifetime of engineering structures. The answer is a multiphysic macroscopic model able to reproduce couplings between the mechanical and environmental fields. For such materials, confidence in the simulation is related directly to one's understanding of each degradation mechanism and to the introduction of such mechanisms in the model; lifetimes being too large for a purely experimental validation over long lifetimes (tens of thousands of hours).The first part of the chapter deals with the modeling of the different microcracking mechanisms. The key phenomenon is the deflection of the matrix cracks in the fiber matrix interphase [2][3][4]: this mechanical fuse protects the fibers from the cracks and enables the development of multiple cracks in the matrix, giving the composite some level of ductility, even though all of its constituents are brittle. The matrix cracking scenario has already been established for woven CMCs [5]. Since the matrix between the yarns is stiffer, but more brittle, and has larger pores than the yarns themselves, it begins to crack first. For a well-densified composite, the corresponding cracks are oriented by the main loading direction and are orthogonal to the applied stress direction, which is a main modeling difficulty. Then, when this crack network nearly reaches saturation, new cracks mainly appear in the matrix inside the yarns. The corresponding cracks are oriented by the fibers: they are orthogonal to the fibers in the longitudinal yarns, and parallel to the fibers in transverse yarns if the main load direction corresponds to the longitudinal yarns. In summary, there are three types of cracks in the damaged material: (i) inter-yarn cracks, (ii) intra-yarn longitudinal cracks, and (iii) intra-yarn transverse cracks.Among composites, CMCs are the most difficult situation for damage modeling. Rather complex closure effects occur for the damage mechanism associated with microcracks when direction is orthogonal to the loading direction and, therefore, is not known a priori. Here, we are developing our answer with a general anisotropic damage theory including microcracks closure effects [6,7]. In order to differentiate between the crack opening and closing effects, which are very pronounced in CMCs, the strain energy is divided into three parts associated with damage due to pure traction, Ceramic Matrix Composites: Materials, Modeling and Technology, First Ed...

show abstract

Section: Multiscale Modeling Of the Oxidation/damage Coupling And Thementioning

confidence: 99%

Section: Modeling Of the Subcritical Cracking Of Fibersmentioning

confidence: 99%

See 1 more Smart Citation

Damage and Lifetime Modeling for Structure Computations

Baranger

Genet

Cluzel

2014

Ceramic Matrix Composites

View full text Add to dashboard Cite

show abstract

“…This mechanism slow down the diffusion of oxygen and thus extends greatly the lifetime of the material. The proposed model [7] can be divided in two parts. The first one, the mechanical one, aims at describing the different crack networks and the fiber failure.…”

Section: General Modeling Frameworkmentioning

confidence: 99%

“…It becomes necessary to use models in order to anticipate the long term behavior over the whole loading range. A second family of models has been developed at LMT-Cacha [5][6][7]. The aim of these models is to predict the mechanical behavior but also the lifetime of the material.…”

mentioning

confidence: 99%

Modeling framework and associated simulation tools for the prediction of damage tolerance of CMC

Baranger

2015

MATEC Web of Conferences

View full text Add to dashboard Cite

Abstract.A modeling framework and the associated simulation tools are presented for the prediction of the mechanical behaviour and lifetime of CMC with self-healing matrix. A macroscopic anisotropic damage model enriched with micro information has been developed, identified and validated using experimental information at different levels including reaction kinetics, fiber failure probability or macroscopic mechanical behavior. The computational cost associated to the proposed model being quite expansive, a method has been setup to construct, automatically, reduced numerical constitutive laws. An illustration is given as well as the associated error estimation.With high manufacturing costs and moderated lifetimes at high temperatures, the use of CMC has been limited to military engine application. Nevertheless, recent developments on self-healing matrices have greatly increase their properties for long lifetimes. It is now possible to use them on civil engine applications in order to improve engine temperatures [1].A first family of models have been developped to predict the mechanical behaviour of CMC under static loadings at the macroscopic scale [2][3][4]. For low lifetimes up to 5 000 h, a purely experimental approach allowed, for a high cost, to handle the problem of certification in the military domain. For civil application (expected lifetimes greater than 50 000 h) within the framework of damage tolerance, a direct experimental strategy becomes unaffordable. It becomes necessary to use models in order to anticipate the long term behavior over the whole loading range. A second family of models has been developed at . The aim of these models is to predict the mechanical behavior but also the lifetime of the material. Loading cases accounted for in the model are static or cyclic mechanical loadings has well as thermal and chemical loadings (oxygen and steam pressures). To get robust results under multi-axial and multiphysic loadings, the model should rely on solid foundations. The aim of this paper is to present that kind of model and then how to implement and use them efficiently in a structural computation framework. First of all, note that a large amount of experimental information and models are available at different scales and on different mechanisms for this material [8][9][10]: from lifetimes on fibers to mechanical behavior on composite coupons by oxidation kinetics. a

show abstract