<p>Preface xv</p> <p><b>Section A Initial State of Adhesive Joints 1</b></p> <p><b>A.1 Adhesion and Interphases: The Basic Ideas in Brief 3</b><br /><i>Wulff Possart</i></p> <p>A.1.1 Introductory Remarks and General Concepts 3</p> <p>A.1.2 Fundamental Adhesive Interactions – the Microscopic Origin and Further Concepts 4</p> <p>A.1.2.1 Physical Intermolecular Forces 4</p> <p>A.1.2.1.1 Bi-Molecular Interactions 5</p> <p>A.1.2.1.2 Physical Interactions Between Condensed Phases 9</p> <p>A.1.2.2 Chemical Adhesion Mechanisms 11</p> <p>A.1.2.2.1 A Brief Sketch of MO Theory 12</p> <p>A.1.2.2.2 An Extension to Macromolecules and Solids – the Electron Band Structure 13</p> <p>A.1.2.2.3 Chemical Reactions – General Aspects 14</p> <p>A.1.2.2.4 Chemical Adhesion Mechanisms in Reactive Epoxies on Inorganic Solids 16</p> <p>A.1.2.2.5 Chemical Adhesion Mechanisms in Reactive Polyurethanes on Inorganic Solids 18</p> <p>A.1.2.3 The Electrostatic Component of Adhesion 21</p> <p>A.1.2.3.1 Mobile Charge Carriers and the Electric Double Layer 22</p> <p>A.1.2.3.2 Continuum Model for the Electric Double Layer Built of Mobile Electrons 23</p> <p>A.1.2.4 Microscopic Adhesion Mechanisms – Co-action at the Phase Boundary 26</p> <p>A.1.2.5 Mechanical Interlocking 27</p> <p>A.1.3 The Interphase – Elemental State of the Adhesive–Adherend Phase Boundary 28</p> <p>A.1.3.1 Polymer Adhesives on Impenetrable Solids 28</p> <p>A.1.3.2 Polymerisation on Solids 32</p> <p>A.1.3.3 The Contact Between Viscoelastic Polymers 34</p> <p>A.1.4 Closing Remarks: Fundamental vs. Practical Adhesion 35</p> <p>References 36</p> <p>Further Readings 41</p> <p><b>A.2 Adhesive Network Formation: Continuum Mechanical Modelling and Simulation 43</b><br /><i>Gunnar Possart and Paul Steinmann</i></p> <p>A.2.1 Introduction 43</p> <p>A.2.2 Phenomenological Observations in Polymer Curing 44</p> <p>A.2.3 One-dimensional Linear Viscoelastic Curing at Small Strains 45</p> <p>A.2.4 Three-dimensional Linear Viscoelastic Curing at Small Strains 52</p> <p>A.2.5 Three-dimensional Curing at Large Strains 55</p> <p>A.2.5.1 Elastic Simulation Framework and Thermodynamic Consistency 55</p> <p>A.2.5.2 Elastic Neo-Hookean Curing Model 58</p> <p>A.2.5.3 Viscoelastic Simulation Framework 59</p> <p>A.2.5.4 Viscoelastic Neo-Hookean Curing Model 59</p> <p>A.2.5.5 The Consideration of Curing Shrinkage 64</p> <p>A.2.6 Material Parameter Evolutions During Curing 65</p> <p>A.2.6.1 Shear Modulus/Second Lamé Parameter 𝜇 66</p> <p>A.2.6.2 Poisson’s Ratio 𝜈 67</p> <p>A.2.6.3 Bulk Modulus 𝜅and First Lamé Parameter 𝜆 67</p> <p>A.2.6.4 Relaxation Time T 68</p> <p>A.2.6.5 Curing Shrinkage s 68</p> <p>A.2.6.6 Degree of Cure 68</p> <p>A.2.7 Epoxy–Ceramics Composite: Photoelasticity and Curing Shrinkage 69</p> <p>Bibliography 73</p> <p><b>A.3 Mechanical Interphases in Adhesive Joints: Characterisation Methods and FE-Simulations 79</b><br /><i>Gunnar Possart and Paul Steinmann</i></p> <p>A.3.1 Introduction 79</p> <p>A.3.2 High-Resolution Shear Testing by Scanning Electron Microscopy 84</p> <p>A.3.2.1 Specimen Preparation and Experimental Set-up 84</p> <p>A.3.2.2 Results and Discussion 88</p> <p>A.3.2.3 FE-Simulations of Adhesive Layers with Interphases 91</p> <p>A.3.2.3.1 Simulation Set-up and Mesh Dependency Study 92</p> <p>A.3.2.3.2 Elastic Interphases 97</p> <p>A.3.2.3.3 Elastoplastic Interphases 101</p> <p>A.3.2.4 Can Curing Shrinkage Fake Interphases? 106</p> <p>A.3.3 Nanoindentations Across Adhesive Joints 110</p> <p>A.3.3.1 Introduction and Experimental Data 110</p> <p>A.3.3.2 Determination of Stiffness and Hardness According to Oliver&Pharr 113</p> <p>A.3.3.3 FE-Simulations of Nanoindentations Across Adhesive Joints 114</p> <p>A.3.3.3.1 Simulation Set-up 114</p> <p>A.3.3.3.2 Results and Discussion 117</p> <p>A.3.4 Scanning Brillouin Microscopy 120</p> <p>A.3.4.1 Introduction and Experimental Set-up 120</p> <p>A.3.4.2 Results and Discussion 123</p> <p>A.3.5 Conclusions and Outlook 126</p> <p>Acknowledgements 128</p> <p>Bibliography 128</p> <p><b>A.4 Fracture Mechanics of Adhesive Joints 135</b><br /><i>Markus Brede</i></p> <p>A.4.1 Introduction 135</p> <p>A.4.2 Linear-elastic Fracture Mechanics 137</p> <p>A.4.3 Fracture in Materials with Energy Dissipation 143</p> <p>A.4.4 The Cohesive Zone Model and Fracture of Joints with Toughened Adhesives 145</p> <p>A.4.5 The Micro-structure of Toughened Adhesives 156</p> <p>A.4.6 Conclusions 161</p> <p>Acknowledgements 162</p> <p>References 162</p> <p><b>Section B Artificial Ageing and Failure of Adhesive Joints 167</b></p> <p><b>B.1 Ageing Phenomena in Polymers: A Short Survey 169</b><br /><i>Alexander Herzig, Michael Johlitz and Alexander Lion</i></p> <p>B.1.1 What Is Ageing? A Brief Introduction to the Deterioration of Polymers 169</p> <p>B.1.2 Different Types of Polymer Ageing 171</p> <p>B.1.3 Experimental Investigations on the Ageing Behaviour of Polymers 181</p> <p>B.1.4 Influence of Ageing on the Properties of Polymers 191</p> <p>References 200</p> <p><b>B.2 Continuum Modelling of Ageing Adhesive Joints 205</b><br /><i>Stefan Diebels, Florian Goldschmidt and Frederik Scherff</i></p> <p>B.2.1 Outline 205</p> <p>B.2.2 Continuum Mechanics of Single-phase Materials 206</p> <p>B.2.2.1 Kinematics 206</p> <p>B.2.2.2 Balance Equations 211</p> <p>B.2.2.3 Constitutive Equations 214</p> <p>B.2.2.4 Viscoelasticity 217</p> <p>B.2.2.5 Example 220</p> <p>B.2.3 Additional Fields 222</p> <p>B.2.3.1 Diffusion of Tracers 223</p> <p>B.2.3.2 Formation of Interphases 225</p> <p>B.2.4 Summary 226</p> <p>References 226</p> <p><b>B.3 Crack Growth in Adhesive Joints: Balance of Energy for Mode I Crack Propagation 229</b><br /><i>Olaf Hesebeck, Udo Meyer, Andrea Sondag and Markus Brede</i></p> <p>B.3.1 Introduction 229</p> <p>B.3.1.1 Dissipation in TDCB Tests 230</p> <p>B.3.1.2 New Approach 232</p> <p>B.3.2 Estimate of Plastic Work Using Finite Element Simulation 233</p> <p>B.3.2.1 Aim 233</p> <p>B.3.2.2 Tensile Tests and Material Model 234</p> <p>B.3.2.3 Choice of Modelling Method 237</p> <p>B.3.2.4 Simulation and Evaluation of Plastic Strain Energy 238</p> <p>B.3.2.5 Evaluation of TDCB Test Results Using the Simulation 244</p> <p>B.3.3 TDCB Tests with Infrared Camera 248</p> <p>B.3.3.1 Aim and Measurement Principle 248</p> <p>B.3.3.2 Experimental Observations 249</p> <p>B.3.3.3 Thermo-Elastic Effect 254</p> <p>B.3.3.4 Estimate of Generated Heat 256</p> <p>B.3.4 Discussion 258</p> <p>B.3.4.1 Estimate of Energy Balance 258</p> <p>B.3.4.2 Limits of Method and Possible Extensions 259</p> <p>B.3.5 Summary 262</p> <p>Acknowledgement 262</p> <p>References 262</p> <p><b>B.4 Joints with a Basic Epoxy Adhesive: Ageing Processes 265</b><br /><i>Léo Depollier, Jesus Ernesto Huacuja-Sánchez and Wulff Possart</i></p> <p>B.4.1 Introduction 265</p> <p>B.4.2 Experimental Strategy 266</p> <p>B.4.2.1 Basic Epoxy Adhesive 266</p> <p>B.4.2.2 Metal Substrates 268</p> <p>B.4.2.3 Sample Preparation 268</p> <p>B.4.2.3.1 Bulk Specimens 268</p> <p>B.4.2.3.2 Adhesive Joints 268</p> <p>B.4.2.3.3 Epoxy Curing Protocol 269</p> <p>B.4.2.3.4 Caloric Glass Transition in Cured EP65:35 270</p> <p>B.4.2.4 Conditions of Artificial Ageing 271</p> <p>B.4.3 Water Diffusion in EP Bulk and Adhesive Joints 273</p> <p>B.4.3.1 Diffusion in Basic Epoxy EP65:35 273</p> <p>B.4.3.2 Water Concentration Profiles in Adhesive Joints 278</p> <p>B.4.4 Mechanical Properties of Fresh and Aged Adhesive Joints 279</p> <p>B.4.4.1 Tensile Tests for Dry Epoxy Bulk Samples 279</p> <p>B.4.4.2 Shear Tests for Freshly Bonded Joints 280</p> <p>B.4.4.3 Bonded Sample Stiffness and Glass Transition During Ageing 286</p> <p>B.4.5 Chemical Ageing Processes 288</p> <p>B.4.5.1 De-bonding due to Corrosion of the Metal Substrates 288</p> <p>B.4.5.2 Chemical Ageing in Metal Joints Bonded with Basic Adhesive EP65:35 291</p> <p>B.4.5.3 Chemical Ageing in EP65:35 Bonded Joints – Liquid Water Versus Moist Air 297</p> <p>B.4.5.4 The Role of the Metal Surface 298</p> <p>B.4.6 Chemical Ageing Versus Physical Plasticisation 299</p> <p>B.4.7 Basic Epoxy Versus Commercial Epoxy Adhesives 300</p> <p>B.4.8 Summary and Conclusions 304</p> <p>Acknowledgement 306</p> <p>References 306</p> <p><b>B.5 Steel Joints with a Basic Polyurethane Adhesive – Ageing Processes 309</b><br /><i>Jesus E. Huacuja-Sánchez, Philipp Engel and Wulff Possart</i></p> <p>B.5.1 Introduction 309</p> <p>B.5.2 PU Adhesive and Sample Preparation 313</p> <p>B.5.2.1 Monomer Mix for the Basic PU Adhesive 313</p> <p>B.5.2.2 PU Bulk Samples and PU–Steel Adhesive Joints 314</p> <p>B.5.3 Artificial Ageing Conditions 314</p> <p>B.5.4 Ageing of Bulk Polyurethane Adhesive PU9010 in Water 315</p> <p>B.5.4.1 Chemical Ageing 315</p> <p>B.5.4.1.1 The Virgin PU9010 Network 316</p> <p>B.5.4.1.2 The Ageing PU9010 Bulk 323</p> <p>B.5.4.1.3 Summary: Chemical Ageing in PU9010 Bulk at Moderate Conditions 329</p> <p>B.5.4.2 Physical Ageing of PU9010 Bulk Samples 330</p> <p>B.5.5 Ageing in Adhesive Joints PU9010–Corundum Blasted Mild Steel S235 331</p> <p>B.5.5.1 Water Diffusion in the Adhesive Joint 331</p> <p>B.5.5.2 Chemical Ageing in the Adhesive Joint 331</p> <p>B.5.5.2.1 Corrosive Attack on the Corundum Blasted Steel in the Adhesive Joint 333</p> <p>B.5.5.2.2 Chemical Ageing of PU9010 in the Adhesive Joint with Steel S235 335</p> <p>B.5.5.3 Physical Ageing in the Adhesive Joint PU9010–Corundum Blasted Steel S235 336</p> <p>B.5.5.3.1 Caloric Glass Transition in the Adhesive Joint 337</p> <p>B.5.5.3.2 Mechanical Modulus in the Adhesive Joint – Evolution During Artificial Ageing 338</p> <p>B.5.6 Conclusions 346</p> <p>Acknowledgement 348</p> <p>References 348</p> <p><b>B.6 Viscoelasticity in Ageing Joints – Experiments and Simulation 355</b><br /><i>Florian Goldschmidt, Stefan Diebels, Frederik Scherff, Léo Depollier, Jesus Ernesto Huacuja-Sanchez and Wulff Possart</i></p> <p>B.6.1 Motivation 355</p> <p>B.6.2 Transport Processes in Adhesives 355</p> <p>B.6.2.1 Fick’s Law of Diffusion 356</p> <p>B.6.2.2 Langmuir-type of Diffusion 356</p> <p>B.6.3 Constitutive Equations 358</p> <p>B.6.3.1 Temperature 359</p> <p>B.6.3.2 Water in the Adhesive 360</p> <p>B.6.3.3 Chemical Ageing 361</p> <p>B.6.3.4 Size Effects 362</p> <p>B.6.3.5 Damage Evolution Model 363</p> <p>B.6.4 Data Evaluation and Results 364</p> <p>B.6.4.1 Data Evaluation 365</p> <p>B.6.4.2 Results – Polyurethane Adhesive 366</p> <p>B.6.4.2.1 Basic Elasticity 366</p> <p>B.6.4.2.2 Viscoelasticity 367</p> <p>B.6.4.3 Results – Epoxy Adhesive 371</p> <p>B.6.5 Summary 372</p> <p>References 373</p> <p><b>B.7 On the Energy Release Rate of Aged Adhesive Joints 375</b><br /><i>Markus Brede, Andrea Sondag, Olaf Hesebeck and Barbara Schneider</i></p> <p>B.7.1 Introduction 375</p> <p>B.7.2 Experimental and Definitions 376</p> <p>B.7.3 Ageing of Polyurethane Adhesive Joints 385</p> <p>B.7.4 Ageing of Epoxy Adhesive Joints 394</p> <p>B.7.5 Summary and Conclusions 403</p> <p>Acknowledgements 404</p> <p>References 404</p> <p><b>B.8 Cohesive Zone Model for Moist Adhesive Joints 405</b><br /><i>Olaf Hesebeck, Florian Goldschmidt and Stefan Diebels</i></p> <p>B.8.1 Introduction 405</p> <p>B.8.2 Transfer from Continuum to Cohesive Zone Model 406</p> <p>B.8.2.1 Viscoelasticity 407</p> <p>B.8.2.2 Damage Behaviour 409</p> <p>B.8.2.3 Validation 411</p> <p>B.8.2.3.1 Tensile Tests of Butt Joints 411</p> <p>B.8.2.3.2 Validation of the Viscoelastic Model 413</p> <p>B.8.2.3.3 Validation of Transfer to Cohesive Zone Model and Damage Model 416</p> <p>B.8.3 Simulation of Diffusion 418</p> <p>B.8.3.1 Finite Element Simulation of Diffusion 418</p> <p>B.8.3.2 Closed-Form Solutions of Diffusion 419</p> <p>B.8.4 Automation of Model Extension 420</p> <p>B.8.4.1 Procedure 420</p> <p>B.8.4.2 Application Tests 422</p> <p>B.8.4.3 Extensibility 423</p> <p>B.8.5 Summary 424</p> <p>Acknowlegdement 425</p> <p>References 425</p> <p><b>Section C Weathering of Adhesive Joints and Life Time Prediction 427</b></p> <p><b>C.1 Adhesive Application Under High-power Ultrasound: Effects on Durability 429</b><br /><i>Barbara Schneider, Jens Holtmannspötter, Markus Spallek and Jürgen von Czarnecki</i></p> <p>C.1.1 A Power Ultrasound Process for Contamination-tolerant Adhesive Application on Critical Surfaces 429</p> <p>C.1.2 Effects of Power Ultrasound 431</p> <p>C.1.2.1 Cavitation 431</p> <p>C.1.2.2 Viscosity Changes 432</p> <p>C.1.3 Determination of the Cleaning Behaviour by Power Ultrasound 433</p> <p>C.1.3.1 Experimental 433</p> <p>C.1.3.2 Weakening of Adhesion by an Applied Contamination 433</p> <p>C.1.3.3 Effect of the Contamination on the Surface Free Energy 434</p> <p>C.1.3.4 Adjustment of the Ultrasonic Process 436</p> <p>C.1.3.5 Results of Mechanical Testing (Single Lap Shear Test) 437</p> <p>C.1.3.6 Cleaning and Improvement of the Ageing Resistance by Using Power Ultrasound 438</p> <p>C.1.3.7 Effects of Ultrasonic Treatment on the Adhesive Assessed by EIS 439</p> <p>C.1.4 Application 442</p> <p>C.1.4.1 Ultrasound-Assisted Primer Application 442</p> <p>C.1.4.2 Automated Removal of Release Agents from Reinforced Plastics by Power Ultrasound 444</p> <p>C.1.5 Summary 446</p> <p>References 447</p> <p><b>C.2 Long-term Behaviour of Adhesively Bonded Timber–Concrete Composites 449</b><br /><i>Werner Seim and Lars Eisenhut</i></p> <p>C.2.1 Introduction 449</p> <p>C.2.2 Hygro-thermal Impact 450</p> <p>C.2.3 Numerical Description of Hygro-thermal Phenomena 452</p> <p>C.2.3.1 Material Models 453</p> <p>C.2.3.2 Mechanical Material Properties 454</p> <p>C.2.3.3 Moisture Transport in Wood 457</p> <p>C.2.4 Experimental Studies 459</p> <p>C.2.4.1 Small-scale Samples Under Artificial Climatic Conditions 460</p> <p>C.2.4.2 Full-scale Specimens Under Natural Climatic Conditions 463</p> <p>C.2.5 Model Validation 464</p> <p>C.2.5.1 Wood Moisture Content 464</p> <p>C.2.5.2 Deflection of the Full-scale Specimens 465</p> <p>C.2.6 Summary and Conclusion 467</p> <p>References 467</p> <p><b>C.3 Adhesive as a Permanent Shear Connection for Composite Beams 471</b><br /><i>Wolfgang Kurz, Markus Kludka, Ruben Friedland and Paul-Ludwig Geiß</i></p> <p>C.3.1 Materials 472</p> <p>C.3.2 Description of the Small-scale Specimens 473</p> <p>C.3.2.1 Steel–Steel Connection 473</p> <p>C.3.2.2 Concrete–Concrete Connection 474</p> <p>C.3.2.3 Steel–Concrete Connection 474</p> <p>C.3.3 Ageing of Lap Shear Specimens 475</p> <p>C.3.3.1 Outdoor Weathering 475</p> <p>C.3.3.2 Accelerated Ageing 475</p> <p>C.3.4 Test Results 476</p> <p>C.3.4.1 Epoxy Adhesive Hilti HIT-RE 500 476</p> <p>C.3.4.1.1 Steel–Steel Specimens 477</p> <p>C.3.4.1.2 Concrete–Concrete Specimens 477</p> <p>C.3.4.2 Polyurethane Adhesive Körapur 666/90 479</p> <p>C.3.5 Large-scale Composite Beams 481</p> <p>C.3.5.1 Testing of the Composite Beams 481</p> <p>C.3.5.2 Test Procedure of the Large Specimens 481</p> <p>C.3.5.3 Test Results of the Composite Beams 483</p> <p>C.3.5.4 Evaluation of the Test Results 484</p> <p>C.3.5.4.1 Evaluation of the Strain Gauges 486</p> <p>C.3.6 Analytical Calculation of the Adhesive Stress in Composite Beams 487</p> <p>C.3.6.1 Effect of the Joint Compliance on the Load–Deformation Behaviour of Composite Beams 490</p> <p>C.3.6.2 Transferability of Small-scale Test Results on Large Components 491</p> <p>C.3.6.3 Analytical Determination of the Deformation Behaviour of Composite Beams in View of an Accelerated Ageing of Adhesives 492</p> <p>C.3.6.4 Analytical Determination of the Tested Composite Beam Results 494</p> <p>C.3.6.5 Complementing the Segment Method by the Method of Lamellae 496</p> <p>C.3.7 Conclusions 498</p> <p>References 498</p> <p><b>C.4 Concluding Remarks 501</b><br /><i>Wulff Possart, Stefan Diebels and Markus Brede</i></p> <p>Index 513</p>