Contact is essentially the definition of parts interacting with one another and/or itself. Abaqus/Standard & Abaqus/Explicit both use General contact and/or Contact pairs for defining contact.
Both are forms of interactions in Abaqus/CAE. Abaqus General Contact was not always available in both Standard and Explicit solvers. They were initially available in Abaqus/Explicit then introduced to Abaqus/Standard from release 6.8-EF in November 2008. It is a very quick and easy way of creating interactions between components but it is not as dirty as you think! The benefit of it is that it can be used alongside contact pairs allowing you to determine what is appropriate where in your analysis. In Abaqus/Standard, general contact can only be applied at the initial step, whereas in Abaqus/Explicit, it can be applied at any step. General Contact can also be used in a very efficient way of just getting Abaqus to find and determine where contacts occur.
General Contact allows users to define contact between all or multiple areas of a model. These are all defined as a single interaction assuming anything can hit anything. This definition is described in the illustration below where there is one contact domain.
Without General contact, there would need to be multiple contact pairs where the user would define what would hit and where as described in the illustration below:
It can be used with both rigid and deformable bodies and is aimed at making it easier to work with models with multiple contacts. However it can increase analysis time due to greater contact areas defined, therefore is not recommended for complex models. Although General Contact assumes anything can come into contact with anything else in the model, surface pairs can be included or ignored to help reduce computation time. It is the recommended, by SIMULIA themselves, type of contact setup for the majority of simulations. It is a must for advanced features such as SPH, FSI, etc.
The following demonstration will display how quick and easy it is to apply a General Contact Interaction in Abaqus/CAE. The model in the following video consists of two parts which make up 6 instances in an assembly. The assembly has been compiled and meshed but no interactions have been defined. The video will demonstrate how to apply a quick general contact and then visualise the result.