Monitoring and Retrofitting Structures with Intelligences

利用智能监控和改造结构

基本信息

批准号：
09044129
负责人：
WU Zhishen
金额：
$ 4.93万
依托单位：
Ibaraki University
依托单位国家：
日本
项目类别：
Grant-in-Aid for international Scientific Research
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1998
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09044129/
关键词：
Existing large-scale brittle structures infrared thermography system laser doppler velocitometer FRP sheets damage assessment Structural health monitoring Intelligent adoptive Structures Repair strenghtening retrofitting

项目摘要

1. The Failure Process evaluation of Brittle Structure system : On this research topic, a failure path approach for time -variant system reliability estimation of brittle structures has been developed The March chain assumption is used to model the cumulative damage under time variant loads. The effect of load overlapping under multiple load processes is investigated. Moreover, a probabilistic model for the randomness of the progressive crack growth in a quasi-brittle material is proposed. The method is implemented by finite element approach with a smeared crack model and R-curve approach.2. Experimental/numerical investigations on bond behavior and its improvement strategies : Through a series of experimental programs on three bending beams, double -shear specimens pulled in tension and simple shear specimens, the bond behavior of concrete-FRP interface influenced by compressive strengths, epoxy characteristics and constructional conditions, the Quantities of FRP sheets, and the rough … More ness of interface etc.has been investigated and several improvement strategies on the bond behavior and self repair of de-bonding have been also proposed. The Cohesive interfacial Crack model based on nonlinear fracture mechanics was also proposed. As the numerical analysis approach, both FEM and BEM methods were used to simulate the dc-bonding propagation.3. Optimization of reinforcement design of FRP sheets : The hybrid concept with different kinds of FRP sheets has been developed to improve the structural behavior and optimum design method of strengthened structures was also proposed through this research. Moreover, a new method to use carbon fiber sheets which was presiressed before they were bonded to the concrete surface is developed to improve different reinforcement effects.4. Defect and de-bonding detection and health structural monitoring system : Two detection systems with both Laser Doppler Velocitometer and Infrared Thermography have been proposed for the de-bonding or other interfacial cracks effectively. And a resistance heating cells embedded in concrete-FRP interface layer is designed in order to make a possible real -time monitoring of interfacial de-bonding. Moreover an active damage detection on crack initiation and its propagation in brittle materials and structures using a build-in network of piezoelectric transducers was proposed.5. Decentralized Adaptive Vibration Control of Complex Structure : In this paper, a new neural network based decentralized control algorithm has been developed for active control of large scale or complex structures which were considered to be controlled with multiple actuators. The concept of information substructures decomposed depending upon the control areas of actuators was introduced successfully in the decentralized control algorithm. Results from computer-simulation studies through the comparison of different control strategies have shown the effectiveness of the proposed method.6. Identification algorithms for the assessment of structural damages : In order to proposed an identification model for a large-scale structure system, firstly, a general framework of inverse analysis is developed for the static parameter estimation problem using Hopfield Neural Network. Secondly, a dynamic localized structural identification method with perturbation technique has been developed for large-scale structures. Moreover, a two-stage identification algorithm for the assessment of structural damages have been also developed using the modal test data. The effectiveness of all of these models were illustrated by numerically simulating several complex structural systems. Less

1。脆性结构系统的故障过程评估：在此研究主题上，已经开发了时间变化的系统可靠性估计脆性结构的可靠性估计该三月链假设用于对时间变体负载下的累积损害进行建模。研究了在多个负载过程中重叠的负载的效果。此外，提出了一种用于准脆性材料中进行性裂纹生长随机性的概率模型。该方法是通过有限元方法采用涂抹裂纹模型和R-Curve方法实现的。2。实验/数值投资对键行为及其改进策略：通过一系列针对三个弯曲光束的实验计划，在张力和简单剪切标本中拉起的双层样本，双层标本，混凝土-FRP界面的键键行为，由压缩强度，压缩强度，环氧特征和构造的范围以及较粗糙的效果等方面的构造和构造的数量以及跨越的策略以及跨越的效果等等。还提出了de键的修复。还提出了基于非线性断裂力学的粘性界面裂纹模型。作为数值分析方法，使用了FEM和BEM方法来模拟DC键入传播。3。通过这项研究，还提出了FRP板的增强设计：与不同种类的FRP板的混合概念，以改善结构行为，并通过这项研究优化了增强结构的设计方法。此外，一种使用碳纤维板的新方法在将其粘合到混凝土表面之前已被预先进行，以改善不同的增强效果。4。缺陷和去键检测和健康结构监测系统：已经提出了有效的键入或其他界面裂纹的两个带有激光多普勒速度计和红外热力计的检测系统。并且设计了一个嵌入混凝土FRP界面层中的电阻加热电池，以便对界面de键进行实时监测。此外，提出了对裂纹倡议的主动损害检测及其在脆性材料和结构中使用压电传感器网络的繁殖。5。复杂结构的分散自适应振动控制：在本文中，已经开发了一种基于神经网络的分散控制算法，用于主动控制大规模或复杂结构，这些结构被认为是由多个执行器控制的。在分散的控制算法中成功引入了根据执行器的控制区域分解的信息子结构的概念。通过比较不同控制策略的计算机模拟研究的结果表明了该方法的有效性。6。评估结构损伤的识别算法：为了提出大规模结构系统的识别模型，首先，使用Hopfield神经网络为静态参数估计问题开发了逆分析的一般框架。其次，已经开发了一种针对大规模结构的动态局部结构识别方法。此外，还使用模态测试数据开发了用于评估结构损伤的两阶段识别算法。通过数值模拟几个复杂的结构系统来说明所有这些模型的有效性。较少的