When two members are jointed together such that no transfer of moment is allowed between members, connection is called pin connection (provided relative axial movement is also restricted),type of joint is called pin joint.
Hereof, what is a rigid structure?
In discrete geometry and mechanics, structural rigidity is a combinatorial theory for predicting the flexibility of ensembles formed by rigid bodies connected by flexible linkages or hinges.
What is the difference between moment connection and shear connection?
A moment connection transfers bending moments from a beam to a column. It is a stiff connection. A shear connection (also called a simple connection) transfers little or no moment. An example of a moment connection is a fully welded endplate to a beam, connected to a column flange.