Test spectrum clipping method achieving monaxial and triaxial random vibration stress equivalence

The invention discloses a test spectrum clipping method achieving monaxial and triaxial random vibration stress equivalence, and the problem that an existing test spectrum determination technique is complex in processing process is mainly solved. The test spectrum clipping method comprises the implementation steps that 1, a maximum Fann equivalent stress value sigmamax, generated when single axes are sequentially loaded with a homotaxial vibration acceleration test spectrum, of a focused point n on a vibration system and a Fann equivalent stress value sigmaxyz, generated when the three axes are simultaneously loaded, of the focused point n are extracted, and the ratio a of sigmamax to sigmaxyz is calculated through a formula a=sigmamax/sigmaxyz; 2, the horizontal coordinate of the monaxial vibration acceleration test spectrum keeps invariable, the corresponding vertical coordinate is reduced by a times of a, and then a clipped vibration acceleration test spectrum is obtained. The test spectrum clipping method can achieve the effect that the Fann equivalent stress value, generated during triaxial vibration, of the focused point n can be made to be equal to the maximum Fann equivalent stress value generated during monaxial sequential vibration, is a simple and convenient method for determining a triaxial vibration test spectrum and can be used for building a triaxial vibration test standard.