Investigation on fatigue and crack propagation life of repaired fuselage butt-joint postprint

Abstract:
A rapid analysis method of fatigue life and crack propagation life for repaired butt-joint is proposed based on three-dimensional finite element analysis.Considering the friction and rivet clamping force,the three-dimensional finite element models of different repaired configurations are established.An approximate model is constructed to represent the variation of pin load with the increase of crack length based on the analysis result.A rapid analysis method for calculation of the stress intensity factor for cracks in butt-joint is proposed based on weight function method,from which a predictive method for the crack propagation life is then developed.The fatigue life and crack propagation life of 4 repaired configurations are analyzed,Results shown that the dangerous positions are all located at the first rivet row in skin,and the pin load of different configurations is quite different.In addition,increasing the number of rivet rows and adopting stepped patch can reduce the pin load of the first rivet row.The fatigue life can be significantly enhanced by reducing the pin load of the first rivet row,while the improvement for crack propagation life is less significant.