Question

Submission Instruction: . Create a Matlab program named my_bar which can solve the following assignments in this document and turn in the hard copy A two bar network is shown in the figure below u2 L1 し2 . Elastic Bar Properties are defined in as follows Bar 1 A1 = 4 in^2 E1 15e6 psi L1 20 irn Bar 2 A2 2.25 in^2 E2 10e6 psi L2 = 20 in Displacement BC's ulx 0 Applied Loading F3 = 20,000 lbf . Use the Internal Forces Approach and the Strain-Displacement, Stress-Strain approach to compute the two element stresses

Answer 1

MATLAB CODE:

my_bar

%L-length of each element
%n-no of elements
%N-No of nodes
%A-Area matrix in sq.in
%K- stiffness matrix
%F- force vector
%ke-element stiffness matrix
L=20;
n=2;
N=n+1;
A=[4 2.25];   
K=zeros(N);
E=[15e6 1e6];
u=zeros(N,1);
F=zeros(N,1);
F(3)=2e4;
a=[1 -1;-1 1];
%loop for stiffness matrix
for i=1:n
K_temp=zeros(N);
ke{i}=(E(i)*A(i)/L)*a;
K_temp(i:i+1,i:i+1)=ke{i};
K=K+K_temp;
end
K_new=K(2:N,2:N);
F_new=F(2:N);
u(2:N)=inv(K_new)*F_new;
u_B=u(N) %displacement at point B
sigma_1=E(1)*(u(2)-u(1))/L;
sigma_2=E(2)*(u(3)-u(2))/L;

冚 3 2 3 22Sin2 20n F320,ooo lb A, E Stsess in basil, ơi 2