Title page for ETD etd-11072008-063632
|Type of Document
||Lacy, David Terrell
||An automated methodology for dynamic force analysis of adaptive spatial trusses
||Master of Science
|Robertshaw, Harry H.
|Cudney, Harley H.
|West, Robert L. Jr.
|Date of Defense
The purpose of this thesis is to develop a formal methodology for determining the
loads occurring in the members of an adaptive truss due to both gravity and acceleration.
This force analysis can be used as the basis for a design code which will
provide truss member dimensions and actuator characteristics. Three different truss
structures are considered. The first is a planar, triangular truss consisting of one
actuated member and two fixed length members. The·second structure is a spatial,
double-octahedral truss with three active members and eighteen fixed length members.
The third structure is a truss consisting of several double-octahedral bays
connected together as a chain. For each structure, the active link motion is first
simulated and the position, velocity, and acceleration history of each of the member
connecting points is calculated. The dynamic equations of motion for each member
are developed and combined to form a system of equations describing the motion of
the entire truss. These equations are then solved to find the forces occurring at each
node. Once the forces are determined, the internal forces in each member can be
found, and the resulting stresses are calculated. The members are also checked for
buckling using Euler buckling theory. The stress calculations are checked against
experimental values and show good agreement for both static only and static and
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