3D Supports that can Exert Optional Couples 2-13-17
Hinge or Bearing
Note: allows rotation about x axis → no reaction couple about x axis.
Prevent rotation about y or z? Maybe
Yes, if another support at B → no need for A to prevent rotation about y or
z → no reaction couple (at A) about y or z. No reaction couple (at A) about
y or z. If there is, the hinge A must prevent rotation about y,z. Example 4.114 without Bearing D
Where the unknowns are Cx,Cy,Cz,T,Mcy,Mcz
6 equations equilibrium.
Center of Gravity (2D)
Point where the weight of a body could be concentrated → resultant of all
individual weights of body element. Weight becomes in reality a system of t