You can use RCFORC data written for contact transducers (*CONTACT_FORCE_TRANSDUCER_PENALTY) to extract any contact forces. Contact transducers are used to record contact forces produced by other contacts (including *CONTACT_AUTOMATIC_GENERAL). A contact transducer is defined like a single surface contact, i. e., you define the slave side only and supply 3 cards of input (cards 2 and 3 can be blank). If you wish, you can define a separate force transducer for each part. You can even break it down further and define a transducer for a set of segments or even a single segment.
Transducers are NOT implemented for 2D contact and should not be defined in a 2D model.
Added master surface to force transducer penalty option to gather force interactions between surfaces in single surface contact.