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Impact Resistance of High Performance Concrete Panels under High Velocity Projectile Collision : 고속충돌 하중을 받는 고성능 콘크리트 패널의 내충격성 평가 및 설계식 개발
| DC Field | Value | Language |
|---|---|---|
| dc.contributor.advisor | 강현구 | - |
| dc.contributor.author | 김상희 | - |
| dc.date.accessioned | 2018-11-12T00:57:30Z | - |
| dc.date.available | 2018-11-12T00:57:30Z | - |
| dc.date.issued | 2018-08 | - |
| dc.identifier.other | 000000153374 | - |
| dc.identifier.uri | https://hdl.handle.net/10371/143153 | - |
| dc.description | 학위논문 (박사)-- 서울대학교 대학원 : 공과대학 건축학과, 2018. 8. 강현구. | - |
| dc.description.abstract | Although many studies on impact and explosions have been made due to the frequent occurrence of collisions and explosions that threaten the safety of concrete structures, it is not easy to predict damage to a concrete panel under high velocity impact loads due to the complexity of the impact mechanism of concrete. In this paper, various experimental and analytical studies are carried out to evaluate the impact resistance of concrete, and a new local impact formula is proposed to predict local damage levels.
In order to evaluate the impact resistance of a concrete panel with various parameters that were not investigated much, three experiments are carried out different. In the first experiment, the effect of steel fibers and wire mesh on impact resistance is investigated. In addition, aggregate size, panel thickness and projectile speed are used as parameters. The second experiment uses concrete strengths of 30 ~ 150 MPa and five kinds of bullets in order to evaluate the impact strength according to both concrete strength and the nose shape of the projectile. The third experiment evaluates the impact resistance of a thin panel using 180 MPa concrete. For the second and third experiments, a small impact test device developed by the author is used. Based on the experimental results, the impact mechanism is classified into six categories: deformed energy of the projectile, elastic penetration resistance energy of the panel, overall deformed energy of the panel, spalling-resistant energy, tunneling-resistant energy, and scabbing-resistant energy. Using these impact mechanism and energy conservation laws, new penetration depth, scabbing depth, scabbing limit thickness, and perforation limit thickness are proposed. The validity of the proposed impact formula is verified using the results of the current experiment and other research. Supplementary nonlinear analysis is performed to investigate how reinforcing bars affect the impact resistance of reinforced concrete panels, as the presence of reinforcing steel was identified as one of the unclarified parameters during the test. In addition, the effects of projectile size, panel area, and thickness on impact resistance, which are insufficiently studied in the experiments, are examined through nonlinear analysis. | - |
| dc.description.tableofcontents | Abstract i
Contents iii List of Tables viii List of Figures x List of Symbols xviii Chapter 1. Introduction 1 1.1 Motivation for Research 1 1.2 Scope and Objectives 9 1.3 Organization 12 Chapter 2. Literature Review 15 2.1 History of Research on Impact Formulae 15 2.2 Existing Impact Formulae 20 2.3 Existing Impact Experiment 36 2.4 Nonlinear Analysis 43 2.4.1 Nonlinear analysis programs 43 2.4.2 Concrete model for nonlinear analysis 47 2.5 Discussion 55 Chapter 3. Design of Small Impact Test Device 57 3.1 Purpose of Contravening Impact Test Device 57 3.2 Impact Test Device Type 60 3.3 Design Process of Impact Test Device 61 3.3.1 Design objectives 61 3.3.2 Overall plan 64 3.3.3 Design of air-compressor and air tank capacity 65 3.3.4 Design of barrel size and details 67 3.3.5 Solenoid valve 74 3.3.6 Experimental chamber 76 3.3.7 Modification of impact test device 78 3.4 Manufacturing Process 81 3.4.1 Air compressor system 81 3.4.2 Barrel and experimental chamber 83 3.4.3 Installation of impact test device 87 3.5 Discussion 90 Chapter 4. Impact Experiment and Performance Evaluation 93 4.1 Specimen Construction 94 4.1.1 First experiment plan 94 4.1.2 Second experiment plan 101 4.1.3 Third experiment plan 105 4.2 Impact Experiment 109 4.2.1 First experiment 109 4.2.2 Second experiment 111 4.2.3 Third experiment 113 4.3 Material Test and Results 115 4.3.1 Material test 115 4.3.2 Discussion of concrete properties for experiment 116 4.4 Analysis of Experimental Results 121 4.4.1 First Experiment 121 4.4.2 Second experiment 139 4.4.3 Third experiment 147 4.5 Empirical Parameters 156 4.6 Discussion 158 Chapter 5. Development of New Energy-Based Impact Formula 163 5.1 Concept of New Formula 164 5.1.1 Materials for impact mechanism 164 5.1.2 Impact mechanism and energy conservation 164 5.1.3 Forces acting in impact mechanism 167 5.1.4 Force on nose of projectile 174 5.2 Properties of Materials Affected by Strain Rate 180 5.2.1 Definition of strain rate 180 5.2.2 Properties of concrete affected by strain rate 186 5.2.3 Properties of steel affected by strain rate 188 5.3 Involved Energies in Impact Mechanism 189 5.3.1 Kinetic energy (EK) 189 5.3.2 Deformed energy of projectile (EDP) 189 5.3.3 Resistance energy to penetration 190 5.4 Derivation of New Energy-Based Impact Formula 204 5.4.1 Penetration depth formula 204 5.4.2 Scabbing depth formula 206 5.4.3 Scabbing limit thickness formula 207 5.4.4 Perforation limit thickness formula 209 5.5 Verification of Developed Impact Formula 210 5.5.1 Comparison between test results and predictions 210 5.5.2 Penetration depth assessment 213 5.5.3 Scabbing depth assessment 226 5.5.4 Scabbing limit thickness assessment 228 5.5.5 Perforation limit thickness assessment 230 5.6 Critical Impact Mechanism 233 5.7 Potential Aplication Example 238 5.8 Discussion 241 Chapter 6. Supplementary Nonlinear Analysis 245 6.1 Modeling of Impact Test Model 246 6.1.1 Validation of concrete model 246 6.1.2 Plan of nonlinear analysis on effect of rebar 251 6.1.3 Projectile aspect ratio 257 6.1.4 Panel area 261 6.1.5 Panel thickness 263 6.2 Results of Nonlinear Analysis 265 6.2.1 Reinforcing bars 265 6.2.2 Projectile aspect ratio 272 6.2.3 Panel area 277 6.2.4 Panel thickness 280 6.3 Discussion 285 Chapter 7. Summary and Conclusions 287 7.1 Summary 287 7.2 Conclusions 288 References 295 국 문 초 록 315 Acknowledgement 317 | - |
| dc.language.iso | en | - |
| dc.publisher | 서울대학교 대학원 | - |
| dc.subject.ddc | 690 | - |
| dc.title | Impact Resistance of High Performance Concrete Panels under High Velocity Projectile Collision | - |
| dc.title.alternative | 고속충돌 하중을 받는 고성능 콘크리트 패널의 내충격성 평가 및 설계식 개발 | - |
| dc.type | Thesis | - |
| dc.contributor.AlternativeAuthor | Sanghee Kim | - |
| dc.description.degree | Doctor | - |
| dc.contributor.affiliation | 공과대학 건축학과 | - |
| dc.date.awarded | 2018-08 | - |
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