Theoretical Investigations on Multi-Fields Coupling and Nonlinear Mechanics of Structures Employing Electromagnetic Materials

By LZU | 01/11/2012 17:28:36 | Views ()

Project Title: Theoretical Investigations on Multi-Fields Coupling and Nonlinear Mechanics of Structures Employing Electromagnetic Materials

Primarily Achieved by: Zheng Xiaojing and Zhou Youhe.

Completed Units: Lanzhou University

Award & Grade: The second-class National Prize for Natural Sciences, P.R.China in 2008.

Brief Introduction to the Project:

For the basic mechanical behaviors like bending, buckling, vibration and dynamic control which are the widely used in electromagnetic materials such as ferromagnetic materials, superconducting materials, giant magnetostrictive materials and piezoelectric materials, we have made intensive and systematic research on the basic theoretical framework, effective calculation method and quantitative analysis, etc.

Main findings and innovations:

  1. The general functional form of the analytical solution and the exact solution for the bending of thin circular plate are constructed and obtained. Some classic problems including the convergence verification of the approximate analytic solution method are solved.
  2. The effective quantitative analysis method and feedback control model based on the wavelet method are proposed for the active control of piezoelectric intelligent structures. The problem of control instability which is difficult with the traditional method due to the coupling between sensing signal and actuating signal is solved. The quantitative rule between thermo-elasticity and nonlinearity is revealed.
  3. The complete theoretical framework and effective analytic method for the multi-field coupling of ferromagnetic structure and superconducting structure are established. The nonlinear constitutive model which characterizes the magneto-mechanical coupling of the giant magnetostrictive material is proposed.
  4. A research route for the nonlinear mechanics based on the multi-field coupling of electromagnetic structure is established. The nonlinear nature and unique mechanical characteristics of multi-field coupling are found and revealed.

The basic theoretical model established was recognized as the the new theory frame which replace the magnetostriction stress tensor and the representative work in this field since the electromagnetic stress tensor given by Maxwell. In addition, the constitutive relation is convenient for theoretical analysis. The research on the dynamic stability of the superconducting levitation system was evaluated as showing the hysteresis characteristics of the levitation force and the distribution of the shielding current in the superconductor. This work was awarded the “The 2007 Van Duzer Prize” by IEEE Council on Superconductivity (it was the first time this prize was awared to chinese scholar). The wavelet analysis method established was cited by the scholor who studied the dynamics and was remarked as the efficient method.

 

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