Solve Differential Equation with initial conditions and function

Hello Everyone,

I have this differential equation: I have defined the function M(x) in the following way:

function M = Moment(x)

a = 800; %mm

b = 200; %mm

L = 1000; %mm

F = 1000; %N

if x<a

V = F*b/L;

M = V.*x;

elseif x >= a

M = F*a*(1-(x/L));

end

end

to solve the differential equation I've defined the following ode function based on previous ones:

xspan = 0:0.0002:1000;

y0 = [0 0];

[x,results] = ode45(@func3,xspan,y0);

function [dy] = func3(x,y)

E = 70000; %N/mm2

I = 32000; %mm4

y1 = y(1);

y2 = y(2);

dy1 = y2;

dy2 = -Moment(x)/(E*I);

dy = [dy1; dy2];

end

The main problem I'm trying to solve is that I have the boundary condition for the displacement y(0) = 0 and y(1000) = 0. I'm able to assign the first BD (i think), but i don't know how to assign the second one, since the solver refears to the function "Moment".

Thank you in advance!

Answer 1

[Alan Stevens]

Try modifying your if statement in Moment. Something like

if x<a
    V =...;
    M = ...;
elseif x>=a && x<L
    M = ...
else
    M = 0;   
end