%CME434 Fall 2006, Homework #3 assigned 09/22/06 due on Monday, 10/02/06

%Open hw3.xls in excel. Note the format of the data and the nomenclature definitions. Subscripts are indicated as in M.e meaning M-sub-e.
%Start MATLAB and begin by opening the workspace hw3.mat in the Workspace Window.
%The workspace now has all the information needed for the 4 Bar 2D truss example given in lecture.
%Do not assume that number of nodes or the number of elements will always be 4.
%Do not use a litteral value when a value is available from the variables in the workspace.
%Exception: for now, you may assume 2D space with 2 components of displacement per node.
%Complete the following using MATLAB:

%1  Write a script to calculate ns, the order of the system (total number of displacements).

%2  Write a script to calculate bar lengths Lx, Ly, L, l=cos(theta) and m=sin(theta) for each of the ne elements.
%Store the results in (1 x ne) row vectors [L.e], [l.e] and [m.e].

%3  Write a script to draw the truss by plotting each element (graph the endpoints) in the same figure.

%4  Write a script to calculate k=AE/L for each element.
%Store the results in (l x ne) row vector [k.e]

%5  Write a script, given nf and FTAB, to initialize the column vector F with the specified applied forces.
%Note: an applied force is zero unless some other value is specified.

%6  Write a Script, given nq and QTAB, to initialize the column vector Q with the specified displacements.
%Note: To create Q a value must be given. For now, let the Q(i) be zero except where another value is given.

%7  Write a script to calculate Ke and Ge for each element.
%Assemble the results in K using K=Sum(Ge'*Ke*Ge)

%8  Write a script to apply the boundary conditions and solves for displacements.
%Assume that Q(1) ... Q(nq) are the known displacements. Some may be non-zero.
%Partition Q, K, and F, solve for the free displacements QF=inv(KF)*(FF-KEF'*QE.

%9  Write a Script to calculate the Reactions FE=KE*QE+KEF*QF.
%Complete Q and F by including the calculated values of QF and FE.


%10  Write a script to open the input data file hw3data.txt and create an initial workspace like the one opened at the start of this assignment.
%Turn in your MATLAB scripts as directed by the T.A.