Mechanical Properties Analysis Of MJ Class HTS Superconducting Magnetic Energy Storage Magnet

With the development of fabrication technology of 2G high temperature superconducting (HTS) materials, the overall performance of HTS tapes is also improving. Meanwhile, its price is gradually reduced. As a result, the practical application for HTS magnet has a vast prospect. The operating temperature of high temperature superconducting magnetic energy storage (SMES) system is much higher than that of high temperature superconducting energy storage system. It can reduce the complexity and costs of the refrigeration system. Compared with the BSCCO, anisotropism of YBCO tapes is weaker. YBCO is a good choice for large SMES magnets because of its better current carrying capacity in liquid nitrogen and high magnetic field. Owing to limited current carrying capacity of a single tape, we need to use several composited tapes for large SMES magnets design to ensure that the inductance of the magnet can not be too large which would increase the magnet response time. Consideration of electromagnetic properties, mechanical properties, thermal stability, etc in SMES magnets design is very necessary. Based on different composite conductors, this thesis designs and optimizes magnets, analyzes mechanical properties of the magnets and puts forward some measures to strengthen the magnet structure. The main work is as follows:First of all, this thesis introduces the calculation method of magnetic field, electromagnetic force and stress strain in high temperature magnet design based on YBCO. The commercial finite element analysis software ANSYS is introduced, especially for its powerful electromagnetic-structure coupling function. The way to deal with the magnet design and related problems is put forward. All these provide a basic reference for the magnets design.Secondly, the possibility and advantages of several kinds of strip and composite conductors used in SMES magnets are analyzed. The composite conductor of CORC that made of four layers of YBCO is designed in this thesis. And the I-B curve of the conductor is calculated according to the existing data.Thirdly, magnets using two kinds of composite conductor are respectively designed from the point of saving the superconducting material and reduce the electromagnetic force. Software MATLAB and ANSYS are used in the designing process. And different design schemes are analyzed and compared.Finally, the thesis analyzes mechanical properties of magnets which are designed in this thesis. Then, several structural strengthening measures for HTS SMES magnets are proposed. Numerical simulation is carried out by using the finite element software. The results show that the proposed method can increase the mechanical stability of the magnets.