Papers by Author: Zhuo Qiu Li

Abstract: The paper deals with the temperature sensitivity of a new type strain sensor named carbon fiber smart layer (CFSL) made of epoxy-matrix composites with short carbon fiber mats. The experiment result indicated that the epoxy matrix CFSL is sensitive to temperature variation. It exhibits NTC effect in -5°C~25°C and exhibits PTC effect in 25°C~50°C. The NTC effect is relatively gentle and the PTC effect is relatively dramatic. The mechanism of both NTC effect and PTC effect is discussed based on the temperature sensitivities of carbon fiber itself and the fiber to fiber interface. Further experiment demonstrated its temperature sensing properties in the temperature scale in which the NTC effect or PTC effect exhibits individually.

Abstract: In order to improve the gauge factor of polymer-matrix carbon fiber reinforced composites (CFRP) for strain sensing, the carbon fiber sensitive interface was constructed in epoxy by effectively overlapping the CFRP laminates in local area. The strain sensitivities of the carbon fiber interface were proved by the cyclic tension test on the base specimens covered by the carbon fiber composites with the sensitive interface, and their much bigger gauge factors were revealed by the comparison with the polymer-matrix continuous carbon fiber composite. The sensitivity of the carbon fiber interface is originated from the change of the interfacial points due to the interfacial stress.

Abstract: Carbon fiber composed with epoxy-matrix is revealed to be a kind of functional composite material, which has sound sensing characteristics. The sensing ability of mechanic-electric character and temperature-electric character of carbon fiber layer based on the epoxy matrix was experimentally discussed in this paper. Through the uniaxial tension the CF layer reveals a good performance by resistance changing with response to the loading. In temperature-resistance testing, CF layer also has a good response to the temperature changing by its resistance varying. Carbon fiber composed with polymer will provides a new kind of sensor which can be used as force sensor and temperature sensor as well.

Abstract: In this paper, large scale wind turbine blade has been taken for example and two harmful conditions have been chosen as the study targets. Taking a 25 m long wind turbine blade, its solid model is built in CAE. Then take advantage of Computational Fluid Dynamics software-FLUENT to analyze and simulate wind pressure of blade surface acted by aerodynamic force. By means of the numerical method to make curve fitting to bring wind pressure to bear on each cross section of blade accurately, and import it into ANSYS to do further analytical work. It shows that the work should be the firm foundation for further analysis of the wind turbine blade.

Abstract: The paper makes a comprehensive study on the sensitivity of a new type strain sensor named polymer-matrix carbon fiber smart layer. The sensitivity to tensile strain was gained by a uniaxial tension test. By a three-point bending test on a FRP bar stuck by the smart layer, the sensitivity to compressive strain was revealed and a lower gauge factor was obtained compared to the sensitivity to tensile strain. In addition, a pure shearing test was designed, revealing the sensitivity to shear strain.

Abstract: Treat continuous carbon fiber with special technology, followed by pasting the electrode pole to it and in epoxy resin, a high resistance-strain sensitivity of polymer-matrix carbon fiber strain sensor can be achieved. Paste this element on the beam of fiber glass reinforced plastics, we tested its linearity、sensitivity、stability, frequency response etc. The results indicate that the sensitivity of this component is more than 400 as well as load frequency less than 10Hz. Its dynamic tracking performance is in relatively sound with no significant response lag.

Abstract: Electrical resistance tomography (ERT) is always used in the field of detection of medicine、prospecting、two phase flow at the present time. It is rarely used to measure structure under condition of loading. In this paper, with the characters of different response - resistance effect showed by carbon fiber felt when attached to the different matrix, we developed a new type of smart layer of carbon fiber composites, the composite material has a very high pressure-resistance sensitivity, combined with ERT technology, the structure surface electrical resistivity distribute can be conversed, thus the structure of the surface of the load situation can be analyzed.