 | Shi Y. Characterization and modeling of the mechanical properties of wound oxide ceramic composites: Diss. ... Dr.-Ing. / Deutsches Zentrum für Luft- und Raumfahrt, Institut für Bauweisen und Strukturtechnologie, Stuttgart. - Köln: DLR, 2017. - xviii, P.19-130.: ill., tab. - (Forschungsbericht; 2017-30). - Res. also Germ. - Bibliogr.: p.123-128. - ISSN 1434-8454
Шифр: (Pr 1120/2017-30) 02
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Vorwort .........................................................
Abstract ........................................................ v
Kurzfassung ................................................... vii
Content ........................................................ ix
List of figures ................................................ xi
List of tables ............................................... xiii
Nomenclature .................................................. xvi
1 Introduction .............................................. 19
2 State of the art .......................................... 21
2.1 Bases of oxide/oxide CMCs ................................. 21
2.2 State-of-the-art in mechanics of CMCs ..................... 26
2.2.1 Concept of toughness enhancing mechanisms for
CMCs ............................................... 26
2.2.2 Modeling of the mechanical properties of CMCs ...... 27
2.2.3 Failure criterion .................................. 29
2.3 Motivation and procedure .................................. 33
2.4 Specifications of the investigated topic .................. 34
3 Experimental Set-Up ....................................... 37
3.1 Non Destructive Inspection Set-Up ......................... 37
3.2 Fiber volume content and porosity ......................... 39
3.3 Mechanical testing ........................................ 40
4 Investigated material WHIPOX .............................. 43
4.1 Processing of plate material .............................. 43
4.2 Microstructural investigation: shrinkage cracks ........... 44
5 Modeling Approach ......................................... 49
5.1 Classical Laminate Theory ................................. 49
5.2 Inverse approach of Classic Laminate Theory ............... 54
5.3 Modified Tsai-Wu failure criterion ........................ 57
5.3.1 Tsai-Wu failure criterion in stress space .......... 57
5.3.2 Tsai-Wu failure criterion in strain space .......... 61
5.3.3 Successive ply failures ............................ 61
5.3.4 Directional failure indices ........................ 63
5.4 Inelastic deformation factor Δ ............................ 64
5.5 Manufacturing factor Ω .................................... 66
5.6 Chain from testing to modeling ......................... 68
6 Characterization of the material properties ............... 71
6.1 Results from experimental testing ......................... 71
6.2 Effects of processing defects ............................. 77
7 Modeling of mechanical properties ......................... 81
7.1 Modeling of elastic properties ............................ 82
7.1.1 Computing the elastic properties of the
equivalent UD-layer ................................ 82
7.1.2 Modeling the elastic properties of WHIPOXTM
without Ω .......................................... 84
7.1.3 Modeling the elastic properties of WHIPOXTM
with Ω ............................................. 85
7.2 Modeling of failure stresses and failure mode ............. 93
7.2.1 Modeling of failure stresses ....................... 93
7.2.2 Modeling of failure mode ........................... 97
7.3 Modeling of failure strain and successive ply failures .... 99
7.3.1 Modeling of failure strain ......................... 99
7.3.2 Modeling of successive ply failures ............... 103
8 Discussion ............................................... 107
8.1 Characterization of mechanical properties ................ 107
8.2 Modeling with the equivalent UD-layer .................... 109
8.3 Applicability of modeling approaches to other CMCs ....... 113
9 Summary and conclusions .................................. 119
10 Literature ............................................... 123
Liste of publications ......................................... 129
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