Fracture Mechanics for a Mode Ⅲ Crack in a Piezoelectromagnetic Material

Analytical solutions for a Griffith crack inside an infinite piezoelectromagnetic medium under combined mechanical-electrical-magnetic loadings are formulated using integral transform method. The singular stress, elec tric and magnetic fields in the piezoelectromagnetic material are obtained by the theory of linear piezoelectromagneticity. Fourier transforms are used to reduce the mixed boundary value problems of the crack, which is as sumed to be permeable, to dual integral equations. The solution of the dual integral equations is then expressed analytically. Expressions for strains, stresses, electric fields, electric displacements, magnetic fields and magnetic inductions in the vicinity of the crack tip are derived. Field intensity factors and energy release rate for piezoelectromagnetic material are obtained. The stresses, electric displacements and magnetic inductions at the crack tip show the traditional square root singularities; and the electric field intensity factor （EFIF） and the magnetic field intensity factor （MFIF） are always zero.     

14×5J新车轮的设计

主要介绍了14×5J车轮的设计过程,本次设计是在符合国家标准的基础上,参考国外相关车轮和夏利轿车车轮的结构特点而完成的,并用计算机对设计进行了分析和评价.