Simulating fixed-target and heavy-ion collisions in LHCb

The LHCb experiment is a fully instrumented forward spectrometer designed for precision studies in the flavour sector of the Standard Model with proton-proton collisions at the LHC. As part of its expanding physics programme, LHCb collected data also during the LHC proton-nucleus collisions in 2013 and 2016 and during nucleus-nucleus collisions in 2015. These datasets provide access to unique kinematic coverage due to the forward detector layout of LHCb. Furthermore, in 2013 LHCb commissioned the internal gas target SMOG, becoming the only LHC experiment with a programme of fixed target physics. Each of these particular collision conditions required a different operational setup, as well as dedicated simulation productions based on heavy-ion Monte-Carlo event generators and interface extensions of the standard LHCb simulation framework. In these proceedings, we present the work done to implement such a variety of simulation productions for heavy-ion collisions, and to validate the produced samples. The future perspectives of the heavy-ion collision simulations at LHCb are also be discussed.