Expert: Veto Varma - 5/10/2006

Question
Dear Sir,
       Greetings to you and hope u r doing well. This mail is just to shoot you with some question in which i have some doubt. The series of questions are.

    1.How to determine degree of freedom for trusses and frames.?
    2.Wat are reduntant and non-reduntant frames and trusses.?
    3.How to determine static and kinematic determinacy.?


thanking you

prince samson

Answer
Hello Prince,

For the trusses every node has translational degrees of freedom and for the frame every node has translational and rotaional degrees of freedom (DOF). These DOFs are reduced by support condition.e.g. if the node is fixed there is no DOFs. This may help you in detrmining DOFs for trusses and frames.  
if you have more unkowns then the available number of equations then the structure is indeteminante. You can count external and internal indetermancy. For trusses there is a simple equation for indeterminacy that you will found in any structural analysis book but as a thumb rule you can get it just by looking it. Whereever in the truss you find extra member not required to complete the triangle, makes one internal indetermanacy. External inderminancy is related to support reactions. Similarly kinematic determinancy is related to DOFs.

If you have any further question give me an email.

Regards
Veto