The Application Of Pattern Recognition To Engineering Structural Dynamic Damage Dentification

Engineering structure is closely linked with human Beings' life; itsquality problem not only connects to the safety of the people's life and wealth,but also causes great loss of social wealth. But engineering structure sometimesexists many types defects and damage in fact. The reliability and security ofstructure can be improved by structural damage detection, the occurrence ofmomentous accident can be avoided, the harm degree of accident can be minished,and the great potential economy benefit and social benefit can be obtained. There are many kinds of structural damage detection method, but dynamicdamage detection technology is prone to realize automatization andminiaturization of system, the foundation of its theory is abundant, theequipment to analyze and test is perfect, the detection result is nicety andcredibility, and dynamic damage detection technology have many abilities, forexample, real time, on line, remote test, controllability and convenience ofpicking up signal, so it is in dominant in engineering structural damagedetection technology, it has wide use foreground in structural damageidentification. There are many kinds of dynamic damage detection methods, there are threetypes of methods in common use: direct analytic method, time order analyticmethod and parameter recognition method. In these three methods, parameterrecognition method recognizes the changes of modal parameter or physicalparameter from metrical input and output signal directly, so it is convenient.From 1960s to this day, the dynamic damage detection technology based on modalanalysis has been used widely. Detection method based on single modal parameteris relative common at present. But the dynamic damage detection based onrecognition of modal parameter belongs to "inverse problem" in dynamics,"inverse problem" sometimes is not single and certain, so the detection resultis likely to be not single, and the wrong detection occurs. So the syntheticallydetection technology based on multi-parameter rises, the research productionof pattern recognition, artificial intelligence and expert system etc. infusesdamage detection with fresh energy. In these methods, pattern recognition isan important embranchment of artificial intelligence, it is a leading directionin today's development of damage detection technology to developintelligentized technology by appliance of theory and technique of patternrecognition or artificial intelligence to structural damage detection. In this paper, cantilever is chosen as typical component, the theory andtechnique of pattern recognition is used to the dynamic detection technologybased on modal analysis, damage pattern is established by damage informationeigenvector from modal parameter, the structural damage position and extensionare recognized respectively, consequently precision of detection is improved.