The project Beräkningsmodeller och underlag för verkans- och sårbarhetsvärdering is part of the Armed Forces research program. The aim of the project is to develop new or implement identified models that describe relevant phenomena of interest in a vulnerability- or lethality (V/L) analysis on a platform level. A specific purpose of the project is to make use of the existing knowledge at FOI on specific phenomena related to the interaction between warheads and protected platforms by implementing it in V/L analysis. The main topics studied in the project during 2020 are: ? a needs analysis for vulnerability and lethality models in naval warfare, ? studies on initiation of propellant charge, ? studies on initiation of explosive ammunition, ? penetration models for long rod projectiles, ? software for penetration of a shaped charge through complex protection systems, ? radar model for active protection systems, ? models for characterizing secondary fragments behind armor, ? secondary effects from anti-tank weapons, ? ballistic fragment impact experiments, ? statistical fragment retardation This annual report gives a brief description of the topics above and other efforts performed by the project during 2018.