Analysis of stress of periodically opened parallel cracks in orthotropic plate

By constructing proper Westergaard's stress function,the stress field around the tip of periodically opened parallel cracks in orthotropic fiber-reinforced composite plate subjected to the load of symmetric tension at infinity was analyzed mechanically by using complex variable function method and approach of undermined coefficients.The conventional definition of stress intensity factor was revised by using the periodicity of the hyperbdic function.The explicit analytic expressions of the stress fields with n as stress intensity factor and also with the revised stress intensity factor were finally obtained.In addition,the scope of stress field was related to the elasticity constant of the materials which was the feature of orthotropic materials different from the isotropic materials.Due to the periodicity of crack distribution,the stress intensity factor would be determined by the shape factor.The result showed that when the interval of the cracks approached to infinity,the orthotropic fiber-reinforced composite plate would be degenerated into one with a single central crack,and the analytic solution obtained would well reflect the periodicity of the crack.