The top and bottom platform of every level is triangular, made up of three

rectangular plates of equal length, fixed to one another. Every level consists of six struts

and six rectangular plates, where in the struts are always at angle with respect to the

plates. The struts are connected to the plates with hinges permitting only a single degree

of freedom. In every level the struts link two different ends of corresponding rectangular

plates in the top and bottom platform.

 4.2 Determination of Stiffness

 The stiffness of the mast is determined by the application of forces on the three

inner vertices of the topmost platform of the mast and the resulting displacement of the

vertices. The forces are applied along the x, y and z axis and a torque is generated by

applying forces on the inner vertices of the topmost triangular platform in a direction

perpendicular to the central axis. For every mast, forces are applied on three points in the

topmost platform and stiffness is measured as the ratio of the sum of total forces applied

to the average of displacements at these three points.


 Kx =- f (4.1)

 3 a

 Where, Kx is the stiffness along the x-axis, fx is the force applied along the x-axis

and 8 x is the displacement along the x-axis. Similarly the stiffness along the other axes

is determined. The torsional stiffness KTZ is determined as the ratio of the sum of all

torque to the average rotation.

 4.3 ANSYS Modeling of the Masts

 Every strut in all three masts is a cylindrical tubular member with an outer radius of

0.35 m and an inner radius of 0.30 m. The height of every level in all the masts is 4.9 m