The shear connection of a composite beam comprises five elements that can all influence behaviour. They include the shear stud connectors, profiled steel sheeting(steel deck) ,
slab reinforcement (rebar or steel mesh) , concrete slab and steel beam top flange.
In such design the shear connects the steel deck to the concrete slab.
Shear Connectors are the most important element in Composite Beam design securing the concrete to steel structural components. Shear  Connectors resist shear forces and increase shear loading capacity in steel buildings,bridges,

Design of the shear stud connector is very important because
1- it affects the choice of a suitable ultimate strength design method for the composite beam
2-The economics and speed of construction
3-The stability of the steel beam
4-The safety of steel beam against collapsing
The ultimate strength of most composite beams is governed by shear stud connector shear capacity