Help with this problem...

the following problem should be completed by creating: function m-file with 4 input parameters and 2 output parameters script m-file using the testing parameters to call the function. Assuming that SI units are used in the formula, you need to perform unit conversions for the testing parameters in the English units

PROBLEM***write a function to plot the displacement of a cantileverd beam under a uniform load. in addition to creating the plot, the function should return the maximum deflection and angle between the horizontal and the surface of the beam at its tip. the formulas for the displacement y and tip angle theta are

y= -(w(x^2)/(24EI))(6(L^2)-4Lx+(x^2)) and theta = (1/6)((W(L^3))/(EI))

where w is the load per unit lenght, E is youngs modulus for the beam, I is the moment of inertia of the beam and L is the lenght of the beam. Test your function with E= 30, I=0.163 L=10, w=100

[Sean de Wolski]

What have YOU done to solve YOUR homework problem?

[ken masters]

function [y,angle]= lab2fun(w,E,I,L)

x=0:L

y=-((w*x^2)/(24*E*I))*((6*L^2)-4*L*x+x^2;

angle=(1/6)*(w*L^3)/E*I;

[ken masters]

SO far I am lost

[Sean de Wolski]

Okay, good, what issue are you having with it?

You'll have to use .* and .^ because you want an element by element solution.

[Sean de Wolski]

and ./

[ken masters]

hos does this look

function [y,angle]= lab2fun(w,E,I,L)

x=linspace(0,L,11);

y=-((w*x^2)/(24*E*I))*((6*L^2)-4*L*x+x^2;

y2=max(abs(y));

if y2~=(abs(y));

end

theta=((w*L^3)/(E*I*6));

plot(x,y);

****any mistakes???

[Sean de Wolski]

I don't know does it? Does it plot a deforming beam?

Okay I do know (it's going to error out because you're doing a matrix exponentiation, not an elementwise one, as I hinted at in my last two comments)

[ken masters]

it gives me

??? Undefined function or variable 'w'.

[Sean de Wolski]

well how'd you call it?

from the command line:

[y ang] = lab2fun(100,30,0.163,10)

[ken masters]

function [y,theta]= lab2fun(w,E,I,L)

x=linspace(0,L,11);

y=-((w.*x.^2)/(24*E*I)).*((6*L^2).*(-4.*L.*x+x.^2));

y2=max(abs(y));

if y2~=(abs(y));

end

theta=((w.*L^3)/(E.*I.*6));

plot(x,y);

result a graph with the following

y =

1.0e+007 *

Columns 1 through 8

0 0.0020 0.0155 0.0511 0.1178 0.2237 0.3755 0.5787

Columns 9 through 11

0.8376 1.1554 1.5337

theta =

3.4083e+003

[Sean de Wolski]

Looks like the numbers are getting bigger - a characteristic of a cantilever beam undergoing loading.

[Matt Fig]

http://www.mathworks.com/matlabcentral/answers/8626-how-do-i-get-help-on-homework-questions-on-matlab-answers

Answer 1

[Bjorn Gustavsson]

You should learn now sooner than later to comment your code! Write between each line what it is supposed to do. If you reach a comment-to-code ratio of something like 2/1 it is no bad thing. This is actually the first thing you should learn. If you make clear and accurate descriptions of what it should do, you will make less mistakes, find mistakes earlier and generaly becomme a better person.

Answer 2

[Danish Saleem]

a cantilever beam is a beam that is clamped at one end and is free at the other end. The deflection y at point x of a beam loaded with a uniformly distributed load w is given by the eaquation y=(-w/24EI)(x^4-4Lx^3+6L^2X^2) where E is the elastic modulus I is the moment if inertia and L is the length of a beam. For beam L=6M, E=70*10^9 Pa I=9.19*10^-6 m^4 and w=800N/m. Make a plot of the deflection of the beam y as a function of x.

Answer 3

[Danish Saleem]

a cantilever beam is a beam that is clamped at one end and is free at the other end. The deflection y at point x of a beam loaded with a uniformly distributed load w is given by the eaquation y=(-w/24EI)(x^4-4Lx^3+6L^2X^2) where E is the elastic modulus I is the moment if inertia and L is the length of a beam. For beam L=6M, E=70*10^9 Pa I=9.19*10^-6 m^4 and w=800N/m. Make a plot of the deflection of the beam y as a function of x.