2D - Truss Analysis help

Hello all, i've been trying to develop a MATLAB code to analyze a 2-D truss system because I thought it would be a good project to further my understanding (i'm a beginner)

My main function script is here:

function Project

E = 10200000;  % Modulus of Elasticity, Aluminum alloy (psi)

A = 200; % Cross-Sectional Area

L = 1; % Length of bar

EA = E*A;

elementNodes = [1 4; 2 4; 3 4; 4 6; 3 6; 3 5; 5 6; 5 7; 6 7];

nodeCoordinates = [0 1 ;0 0 ;1 1 ;1 0 ;2 1 ;2 0 ;3 1 ];

numberElements = size(elementNodes,1);

numberNodes = size(nodeCoordinates,1);

xx = nodeCoordinates(:,1);
yy = nodeCoordinates(:,2);

GDoF = 2 * numberNodes; % degrees of freedom

U = zeros(GDoF,1); % Displacement 

force = zeros(GDoF,1);

% gravitational loads

force(4)= -2500;
force(5)= -2500;
force(6)= -2500;
force(7)= -5000;

% system stiffness matrix

[stiffness]=formStiffness2Dtruss(GDoF,numberElements,elementNodes,numberNodes,nodeCoordinates,xx,yy,EA);

% boundary conditions

prescribedDoF = [1 2 10]';

% Solution

displacements = solution(DoF,prescribedDoF,stiffness,force);

us = 1:2:2*numberNodes-1;
vs = 2:2:2*numberNodes;

end

---------------------------- My second script formStiffness2Dtruss (stiffness matrix)- is here :

function formStiffness2Dtruss

elementNodes = [1 4; 2 4; 3 4; 4 6; 3 6; 3 5; 5 6; 5 7; 6 7];

nodeCoordinates = [0 1 ;0 0 ;1 1 ;1 0 ;2 1 ;2 0 ;3 1 ];

numberElements = size(elementNodes,1);

numberNodes = size(nodeCoordinates,1);

stiffness = zeros(numberNodes);

for e=1:numberElements;

% elementDof: element degrees of freedom (Dof)

GDoF=elementNodes(e,:) ;

stiffness(GDoF,GDoF)=stiffness(GDoF,GDoF)+[1 -1;-1 1];

end

end

--------------------------- When I try and run the main function I get the error

Error using formStiffness2Dtruss
Too many input arguments.

Error in Project (line 26)
[stiffness] =
formStiffness2Dtruss(GDoF,numberElements,elementNodes,numberNodes,nodeCoordinates,xx,yy,EA);

--------------------------- I'm not sure what's really going on and how to fix the problem. Any help would be greatly appreciated! Thanks! (To clarify the second script (stiffness matrix) runs fine on it's own)

[Rick Rosson]

Functions and scripts are two very different things in MATLAB.

Answer 1

[marrwa manaa]

plez if you complete ur program,send to me function script

Answer 2

[per isakson]

See:

• Programming Scripts and Functions
• Functions, Programs that accept inputs and return outputs
• Base and Function Workspaces

and do a few simple exercises