Objectives  The shock resistance standards of the ship's elastic isolation and installations system are all aimed at the isolation system as a whole, and there is no decomposition method of the shock resistance design indexes for the installations, which limits the shock resistance demonstration and development of the installations.

  Methods  In this paper, the main factors of the shock environment of the elastic isolation installations are calculated and analyzed by using Finite Element Analysis(FEA) method, including the weight, the position of gravity center, the area of shock isolator, etc. Then the calculation model for the shock environment of the elastic isolation installations is simulated by the established centralized mass model. Based on this centralized mass model, the shock resistance indexes of a double-layer isolation installation are analyzed and calculated, and the shock environment of this installation is given.

  Results  The results show that, the weight factor has the most significant influence on the shock environment, especially on the deck area where the base impedance is smaller; the influence of the position of gravity center and the area of shock isolator on the shock environment is negligible.

  Conclusions  The standard input environment spectrum can be decomposed to obtain the shock resistance indexes of the elastic isolation installations by the calculation model, and these indexes can provide reference for the subsequent shock resistance design of the installations.