No abstract

Giant magnetostrictive actuator (GMA) is a new type of vibration control driving device. Since it has a lot of nonlinear, its performance model has been can't descrip good. This paper describes the self-made physical design of GMA, develop the GMA performance research experiment. For different excitation voltage, GMA was studied respectively the dynamic response with or without the bias magnetic field. And according to the application of GMA,verified under the condition of have a bias current, the accuracy of the magnetic coupling force curve of the GMA. According to the results of the validation, its curve can better describe the dynamic performance of giant magnetostrictive actuator.

Based on the Jiujiang Bridge Structural Health Monitoring System, lots of data of cable tension and temperature have been acquired. The preliminary analysis of the cable tension and the corresponding temperature shows that there is a long-term growth trend for the cable tension, and exists a certain correlation between the cable tension and the temperature. Using linear fitting method, the growth trend term of the cable tension and the correlation between the cable tension and the temperature of the typical cable are analyzed rationally. By getting rid of the long-term growth trend term and the influence of temperature for the cable tension, the early warning limit of the cable tension state evaluation is determined.

In order to improve the accuracy of cable tension test, the motionequation of the stay cable with the rubber damper was established bases on the principleof Hamilton. First, the correction method for the damping coefficient of rubberdamper and cable tension was proposed according to the higher modal frequencyand measured frequency of cables difference. Then, take the cable of DongtingLake Bridge as an example, the cable tension was calculated by the proposedmethod and compared with the results of measurement by frequency method.Results showed that the proposed method can improve the accuracy of cabletension test and can effectively evaluate the cable tension condition of thecable-stayed bridge.

It is seriously different about characteristics of the mean wind speed between a deep gorge and plains, because of the deck of Aizhai bride to deep gorge bottom up to 335m. Characteristics of the mean wind speed in the deep gorge at the Aizhai bridge site are investigated based on field measurement using three 2D anemometers. The plan of field measurement was induced, and the wind speed, fluctuating wind speed and the 10min average wind speed with 10 days as a unit was analyzed. It if found that wind direction is basically consistent with the gorge toward. Based on the Wind-Resistant Design code, the surface roughness coefficients was fitted about 0.29, and very close to D class of the wind code.