Rui Miranda Guedes' research has been developed on polymer-based composite materials. His main interest is in the durability and long-term prediction of the mechanical behaviour of composite structures. This includes modelling of time-dependent behaviour (viscoelastic/viscoplastic), hygrothermal effects and physical ageing. More recently, he has worked on biodegradable medical devices for ligament repair. He has been the principal investigator in two research programmes funded by the Portuguese Science Foundation (FCT) to develop biodegradable solutions for augmentation devices used in ACL repair.