tesi A. Caggiano.pdf - EleA@UniSA - UniversitÃ degli Studi di Salerno

More documents

Recommendations

Info

$3Eterov e)ce(te/rou sofo\v to/ te pa/lai to/ te nu=n. Ou ... - EleA@UniSA$

Chapter 5. Model performance and numerical predictions42 θ 30 °ρ f 5.042θ 30 °ρ f 5.0σMPa02 PlainσMPa02total dowel strength12 dowel strengthExperimental data40.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7umm40.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7ummτ MPa1086θ 30 ° 4 2 Experimental dataPlainρ f 5.000.0 0.2 0.4 0.6 0.8 1.0 1.2vmmτ MPa108642θ 30 °ρ f 5.0total dowel strength12 dowel strength00.0 0.2 0.4 0.6 0.8 1.0 1.2vmmabFigure 5.13: (a) Experimental test by Hassanzadeh [1990] and numerical predictions for SFRCwith “Dramix type I” fibers with ρ f = 5.0% and (b) effect of the dowel strength on the stressopeningdisplacements in mixed-modes offracture. prediction with the plain interface regarding the experimental results on plain concretetests by Hassanzadeh [1990]. On the other hand, the results also illustrate the significantinfluence of fiber reinforcements on the peak strength and post-peak ductility of theconcrete panel response (when ρ f = 5.0%).τ u u Figure 5.13b deals with the stress-crack opening predictions of SFRC when a reductionof the 50% for the dowel strength is considered. Model predictions mainly capture thefundamental influence of the dowel effect on the overall response behavior under mixedfailure modes. As expected, it controls thetransverse interaction between concrete andsteel fiber in this complex failure mode.τ 5.2 Cracking analysis of the proposed interface model for FRCCThis section is aimed at analyzing the influence of steel fibers and the stress statev v lying on the initial yielding surface on the post-cracking performance and failure104 uu
5.2. Cracking analysis of the proposed interface model for FRCCmodes. As a matter of principle, the method applied herein could be intended as asimilar approach as the one used for continuum-based models, where the localizationanalysis is mainly performed by employing the analytical solution of the classicaldiscontinuous bifurcation condition [Folino, 2012]. Strong differences can be notedbetween the localized failure analyses of classical continuum approaches comparedwith the discontinuous analysis proposed and discussed in this section.The numerical results presented in this section are based on the cracking analysis byconsidering different SFRC qualities and load scenarios. They illustrate a wide range offailure modes which characterize the post-peak response of both plain concrete andSFRC under different stress histories. Moreover, a dimensionless “cracking indicator” isdiscussed and analyzed.5.2.1 Post-cracking behaviorAn extensive post-cracking analysis is proposed based on the FRCC interface modeloutlined in section 5.1. For this purpose, several interface cracking conditions areconsidered for different load scenarios. Following the normalized indicator for diffusefailure by Hill’s condition of stability [Etse, 1992, Etse and Willam, 1994] in smearedcrack models, it is proposed the following normalized “Cracking Indicator” (CI) fordiscrete crack condition as in case of interface models,C I (θ,ρ) = N t · E ep · NN t · E · N(5.3)being θ the initial cracking angle (with tanθ = u/v as highlighted in Figure 5.14) and Nthe unit vector defining the normal of a potential cracking direction expressed asN = [ N1 , N2 ] t = [cos(ρ),sin(ρ)] t (5.4)The angles ρ is depicted in Figure 5.14 and describes the set of all possible vectors Nof the failure surface. E ep and E are the constitutive tangent operator and the elasticone, respectively, defined in Chapter 3. The superscript t deals with the transpositionvectorial operation.The performance of the “cracking indicator” is proposed in terms of the ρ-angle (betweenN and the σ T direction, as depicted in Figure 5.14). Particularly, ρ = π 2 indicatesa pure tensile fracture mode path, while ρ = 0 outlines a direct shear without dilatancy.For any given θ angle, a particular value for ρ (labeled as critical one ρ cr ) exists for105
Page 1 and 2:
Dottorato di Ricercain Ingegneria d
Page 7:
AcknowledgementsI would like to exp
Page 10 and 11:
Abstractinclusion of fibers and the
Page 13:
ContentsAcknowledgementsAbstractTab
Page 16 and 17:
Contents8.6.1 Tensile tests . . . .
Page 18 and 19:
List of Figures2.1 Fine and coarse
Page 20 and 21:
List of Figures4.16 Pull-out simula
Page 22 and 23:
List of Figures6.14 Crack paths of
Page 25:
List of Tables2.1 Mix design per cu
Page 28 and 29:
Chapter 1. Introduction1.1.1 Fiber
Page 30 and 31:
Chapter 1. Introductionthe fiber ad
Page 32 and 33:
Chapter 1. Introductionand mechanic
Page 34 and 35:
Chapter 1. Introduction[Vrech and E
Page 36 and 37:
Chapter 1. IntroductionDespite the
Page 38 and 39:
Chapter 1. Introduction(Figure 1.4)
Page 40 and 41:
Chapter 1. IntroductionFigure 1.8:
Page 42 and 43:
Chapter 1. Introductionfor structur
Page 44 and 45:
Chapter 1. Introductioncracking beh
Page 46 and 47:
Chapter 1. Introduction• "c" if 0
Page 48 and 49:
Chapter 1. Introductionsumed due to
Page 50 and 51:
Chapter 1. Introductionaleatoric na
Page 52 and 53:
Chapter 1. IntroductionFigure 1.13:
Page 54 and 55:
Chapter 1. IntroductionElement Meth
Page 56 and 57:
Chapter 2. Experimental characteriz
Page 58 and 59:
Page 60 and 61:
Page 62 and 63:
Page 64 and 65:
Page 66 and 67:
Page 68 and 69:
Page 70 and 71:
Chapter 3. Zero-thickness interface
Page 72 and 73:
Page 74 and 75:
Page 76 and 77:
Page 78 and 79:
Page 80 and 81: Chapter 3. Zero-thickness interface
Page 93 and 94: 4 Bond behavior of fibers in cement
Page 95 and 96: 4.2. Bond behavior of fibers in con
Page 97 and 98: 4.3. Elasto-plastic joint/interface
Page 107 and 108: 4.4. Fracture energy-based interfac
Page 109 and 110: 4.4. Fracture energy-based interfac
Page 111 and 112: 4.5. Numerical results and experime
Page 117 and 118: 4.6. Closing remarksMPa3.02.5Pi N2.
Page 119 and 120: 5 Model performance and numericalpr
Page 121 and 122: 5.1. Numerical analysesones mention
Page 123 and 124: 5.1. Numerical analysesshown in Fig
Page 125 and 126: 5.1. Numerical analysesconsidered,
Page 127 and 128: 5.1. Numerical analysestic behavior
Page 129: 5.1. Numerical analysesσ MPa121086
Page 133 and 134: 4 03 02 01 001 0 09 08 07 06 05 04
Page 135 and 136: 5.2. Cracking analysis of the propo
Page 137 and 138: 5.2. Cracking analysis of the propo
Page 139: 5.3. Closing remarksconnecting node
Page 142 and 143: Chapter 6. Structural scale failure
Page 167 and 168: 7 Cracked hinge numerical modelfor
Page 169 and 170: 7.1. Basic assumptionsSection at no
Page 171 and 172: 7.1. Basic assumptions1997, Stankow
Page 173 and 174: 7.2. Bond-slip bridging of fibers o
Page 175 and 176: 7.4. Numerical predictionsvertical
Page 177: 7.5. Closing remarksthe experimenta
Page 180 and 181:
Chapter 8. Elasto-plastic microplan
Page 182 and 183:
Page 184 and 185:
Page 186 and 187:
Page 188 and 189:
Page 190 and 191:
Page 192 and 193:
Page 194 and 195:
Page 196 and 197:
Page 198 and 199:
Page 200 and 201:
Chapter 9. Conclusionsof first-crac
Page 202 and 203:
Chapter 9. Conclusionsfibers in con
Page 204 and 205:
Chapter 9. Conclusions9.6 Future re
Page 206 and 207:
BibliographyN. Banthia and N. Nanda
Page 208 and 209:
BibliographyM. Butler, V. Mechtcher
Page 210 and 211:
BibliographyCUR. Bepaling van de Bu
Page 212 and 213:
BibliographyEN-12390-3. Testing of
Page 214 and 215:
BibliographyT. Guttema. Ein Beitrag
Page 216 and 217:
BibliographyE. Kuhl, P. Steinmann,
Page 218 and 219:
BibliographyO. Manzoli, J. Oliver,
Page 220 and 221:
BibliographyK. Park, G. Paulino, an
Page 222 and 223:
BibliographyI. Singh, B. Mishra, an
Page 224:
BibliographyG. Wells and L. Sluys.
show all

tesi A. Caggiano.pdf - EleA@UniSA - UniversitÃ degli Studi di Salerno

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?