| 摘要: |
| 为了探讨钢筋混凝土Ⅰ-Ⅱ复合型断裂过程，基于断裂试验同步采集的声发射信号建立灰色-尖点突变模型，识别断裂过程的临界突变点，分析能量释放率、振铃计数等声发射参量随时间变化的规律以及三维损伤定位.结果表明：能量释放率等参量在跨中开裂和临界荷载时出现突增，基于振铃计数率的灰色-尖点突变模型可以有效判别钢筋混凝土Ⅰ-Ⅱ复合型断裂过程的裂尖起裂、跨中开裂和临界荷载3个状态，试件断裂过程中跨中附近存在大量损伤.研究成果可以为混凝土结构裂缝稳定性分析及预警系统的建立提供基础. |
| 关键词: 灰色理论 尖点突变模型 钢筋混凝土 Ⅰ-Ⅱ复合型断裂 声发射参量 |
| DOI：10.3969/j.issn.1007-9629.2022.01.006 |
| 分类号:TV331 |
| 基金项目:国家自然科学基金资助项目（52101313，51879168，51878315）；重庆市技术创新与应用发展专项重点项目（cstc2019jscx-gksbX0013）；重庆市自然科学基金创新群体项目（cstc2020jcyj-cxttX0003）；住房和城乡建设部2019年科学技术计划项目（2019-K-053）；江苏省高等学校自然科学研究面上项目（19KJB570003）；高性能土木工程材料国家重点实验室开放基金资助（2019CEM012） |
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| Mixed Mode Ⅰ-Ⅱ Fracture Process of Reinforced Concrete Based on Grey and Cusp Catastrophe Theory |
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GONG Nina1,2, HU Shaowei3, FAN Xiangqian4, CAI Xiaoning1
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1.School of Civil and Ocean Engineering， Jiangsu Ocean University， Lianyungang 222005， China;2.College of Mechanics and Materials， Hohai University， Nanjing 210098， China;3.College of Civil Engineering， Chongqing University， Chongqing 400045， China;4.Nanjing Hydraulic Research Institute， Nanjing 210029， China
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| Abstract: |
| In order to study the mixed mode Ⅰ-Ⅱ fracture process of reinforced concrete， a grey and cusp catastrophe model was established based on the acoustic emission signals to identify thecritical mutation points of the fracture process. Meanwhile， the variations of energy release rate and ringing counting with time and 3D crack source locations were analyzed. The results show that some acoustic parameters， such as the energy release rate， increase abruptly in the conditions of crack at mid-span and critical load， and the grey and cusp catastrophe model based on ring counting rate can effectively distinguish the three critical conditions of mixed mode Ⅰ-Ⅱ fracture process like crack initiation at notch tip， crack at mid-span and critical load. There is a lot of internal damage near the bottom of the mid span during the mixed mode Ⅰ-Ⅱ fracture process. The conclusion can provide the basis for the stability analysis of concrete structure cracks and the establishment of early warning system. |
| Key words: grey theory cusp catastrophe model reinforced concrete mixed mode Ⅰ-Ⅱ fracture acoustic emission parameter |
