2008年清华大学信息技术研究院系列学术报告7

Dr. Chang Zhang（张昶） is the director of hardware division at Acellent Technology Inc. He obtained his Ph.D degree from Electrical Engineering and Computer Engineering department, University of Maryland, College Park, and MS, BS degrees from Department of Automation，Tsinghua University . His expertise is in electronics and electrical design, signal processing and analysis. He has published many papers in the structural integrity monitoring filed. He also holds 6 US patents in this filed.

Abstract

Structural Health Monitoring (SHM) is increasingly being evaluated by the industry as a revolutionary method to improve the safety and reliability of structures and thereby reduce their operational cost. The SHM system can be applied to detect damages for composite and metal structures when they are in service. Acellent’s SHM system is based on the SMART technology that originated from Stanford University.

There are two types of SHM systems: The active system and the passive system. Typically, the active SHM system consists of a waveform generator, a high-voltage wideband amplifier, sensor network, data acquisition hardware and analysis software. First, the system sends an electrical signal through the waveform generator and high-voltage amplifier to a sensor in the sensor network. Then the sensor converts this electrical signal to an ultrasonic stress wave that travels through the structure. The stress wave is picked up by the other sensors in the sensor network. These sensors convert the mechanical wave back to an electrical signal, which is captured by the data acquisition hardware. When damage is present in the structure, the stress waves pass by the damage and change their properties correspondingly. The waveform changes will be reflected in the changes of the electrical signals correspondingly. These changes are automatically interpreted by the analysis software to give an indication of damage. The passive system does not need the waveform generation since all sensors listen to the structure responses constantly. The excitation is from the physical impacts to the structure.

This talk introduces the principles of the SHM system and the SMART technology. The system design and applications of the technology are introduced too.