The non-linear equations of strings under a concentrated load were derived. The formulae of the linear frequency and the governing equation of the primary resonance were obtained by Galerkin and Multiple-dimensioned method. The reason of the loss of load in practical engineering was addressed. The bifurcation graphics and the relationship graphics of bifurcate point with concentrated load and the span length of the cable were obtained by calculating example. The results show that formula of the linear frequency ...
