COMBINED GENETIC AND SEQUENTIAL QUADRATIC PROGRAMMING ALGORITHMS FOR VIBRATION- BASED STRUCTURAL HEALTH MONITORING | ||||
| The International Conference on Civil and Architecture Engineering | ||||
| Article 19, Volume 6, 6th International Conference on Civil and Architecture Engineering, May 2006, Page 89-101 PDF (116.49 K) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/iccae.2006.45762 | ||||
 View on SCiNiTO | ||||
| Authors | ||||
| S. Y. MAHFOUZ; M. S. AMIN | ||||
| Ph.D, Civil Engineering Department, Military Technical College, Egyptian Armed Forces, Egypt. | ||||
| Abstract | ||||
| Structural Health Monitoring (SHM) of a structure is a requirement desirable for many engineering structures in both civil and aerospace applications. Early warning of impeding disasters, if not identified on time, damage may have serious consequences, both safety related and economic. However, the complexity of large structures and the difficulty in accessing them makes the use of traditional Non-Destructive Evaluation (NDE), such as visual inspection and instrument evaluation methods, impractical. An effective alternative is the use of methods that depend on Vibration-Based Damage Identification (VBDI). These methods are based on measurement of changes in the modal characteristic of the structure, that is, its frequencies and mode shapes, to identify changes in its physical properties. Therefore, measurement and monitoring of vibration characteristics should theoretically permit the detection of both the location and severity of damage. In the present paper, the output error method of damage identification has been used to assess the presence and severity of damage in steel structures. The identification problem is formulated as optimization problem to find parameters describing the presence and location of damaged elements in a structure by minimization of discrepancy of the modal response predicted by FE analysis from the test data (mixed analytical-experimental approach). A typical portal frame has been chosen for experimental measurements. The modal parameters were measured through modal testing. Two approaches are introduced to solve the identification problem. The first approach deals with a discrete problem that is solved by Genetic Algorithm (GA). The second treats a mixed discrete-continuous problem that is solved by a combination of GA and Sequential Quadratic Programming (SQP), in which the GA is used to produce a high quality starting guess for the (SQP) method that is applied to accurately identify damage. It is found that the first approach was able to identify damage in case of moderate and sever simulated damage, while the second approach is capable to identify damage in case of light damage. | ||||
| Keywords | ||||
| Vibration-based damage detection; structural health monitoring; Optimization; Sequential Quadratic Programming; Genetic Algorithm | ||||
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