Objectives  Design shock spectra are used as crucial inputs for shock response analysis of equipment mounted on submarines. In order to study the spectrum dip characteristics of installed large-mass ship-borne equipment,

  Methods  through finite element numerical simulation of the submarine cabin structure, this paper, using a submarine as an example, investigates the variation of shock spectrum with mass and stiffness of shipboard equipment in different connection forms. The spectra obtained are then compared to that of the widely used national military standards GJB1060.1-91.

  Results  The results show that for single-DOF systems, the spectra specified in GJB1060.1-91 standards are more conservative in lowshift zoneand highacceleration zonefrequency zones, while at medium frequency zonespeed zone, the response spectrum derived from the current research is greater than the response spectrum given in GJB standard. For multi-DOF systems, ignoring the interaction effect between various orders of modes following the national military standard leads to conservative calculation results. In addition, the connection between equipment and cabin have a strong effect on response of the equipment.

  Conclusions  The current study has obtained the influence of various factors on the spectrum dip effect, which may be significant in the anti-shock design of massive equipment mounted on submarines.