I am unable to get the deflection of beam correctly and the plot is incorrect.Even when i am using the right code. Also i tryed to distribute my beam into sections.

Question

Vruddhi 2024-2-12

0
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https://ww2.mathworks.cn/matlabcentral/answers/2081026-i-am-unable-to-get-the-deflection-of-beam-correctly-and-the-plot-is-incorrect-even-when-i-am-using-t

评论： VBBV 2024-2-14

% Plot the bending of a beam with rectangular cross section

% The cross section is in the plane of y-z

% The longitudinal axis of the beam is parallel to the x axis

scale=50;

E= 1.999*10^11; % N/m2

nu = 0.3;

I= 7.74.*10^-7; % m^4

H = 0.0762;% m

R1 = 2224; % N

R2 = 2224; % N

P = 2224; % N

L = 3.0; % m

L1= 0.91; % m

L2= 2.09; %m

N=20;

x=(0:L/N:L);

DIM =size(x);

y= zeros(DIM);

figure(1)

plot(x,y,'.-')

axis equal

hold on

xlabel('Distance(m)')

ylabel('vertical deformation (m)')

title('Deformation of a beam')

xd=x;

yd=y;

for ii=1:length(x)

v=(1/E*I).*(2224*x(ii).^3/6)-(2208.021*x(ii)-(2224*(x(ii)-L1).^3/6)...

-(2224*(x(ii)-L2).^3/6));

yd(ii) = y(ii)+scale.*v;

end

figure(1)

plot(xd,yd,'o-')

axis equal

hold on

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Chuguang Pan 2024-2-12

The plot like a sine curve, maybe the code to calculate the deflecction of beam is incorrect.

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Answer 1

VBBV 2024-2-12

编辑：VBBV 2024-2-12

在 MATLAB Online 中打开

scale = 50;

E= 1.999*10^11; % N/m2

nu = 0.3;

I= 7.74.*10^-7; % m^4

H = 0.0762;% m

R1 = 2224; % N

R2 = 2224; % N

P = 2224; % N

L = 3.0; % m

L1= 0.91; % m

L2= 2.09; %m

N=50;

x=(0:L/N:L);

DIM =size(x);

y= zeros(DIM);

% figure(1)

% plot(x,y,'.-')

% axis equal

% yyaxis right

xd=x;

yd=y;

for ii=1:length(x)

v=(1/(E*I)).*((2224*x(ii)^3)/6-2208.021*x(ii)-(2224*(x(ii)-L1)^3)/6 ...

-(2224*(x(ii)-L2)^3)/6);

yd(ii) = y(ii)+scale.*v;

end

figure(1)

plot(xd,real(yd),'o-')

axis equal

xlabel('Distance(m)')

ylabel('vertical deformation (m)')

title('Deformation of a beam')

3 个评论
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Vruddhi 2024-2-12

It is a simply supported beam with two point loads equidistant from the support. And i am new to use this software. Kindly share the code of solving deflection in sections. As the value of deflection at ends will be zero.

VBBV 2024-2-14

在 MATLAB Online 中打开

The code which you shared in question is modified to give outputs as shown in this thread. If you run the code, you would get a deflection curve shown from modified code with correct values. To obtain defelction in sections you need to split the equation as below

scale = 50;

E= 1.999*10^11; % N/m2

nu = 0.3;

I= 7.74.*10^-7; % m^4

H = 0.0762;% m

R1 = 2224; % N

R2 = 2224; % N

P = 2224; % N

L = 3.0; % m

L1= 0.91; % m

L2= 2.09; %m

N=50;

x=(0:L/N:L);

DIM =size(x);

y= zeros(DIM);

% figure(1)

% plot(x,y,'.-')

% axis equal

% yyaxis right

xd=x;

yd=y;

for ii=1:length(x)

v=(1/(E*I)).*((2224*x(ii)^3)/6-2208.021*x(ii)-(2224*(x(ii)-L1)^3)/6 ...

-(2224*(x(ii)-L2)^3)/6);

yd(ii) = y(ii)+scale.*v;

v1(ii) = (1/(E*I)).*(2224*x(ii)^3)/6; % section 1

v2(ii) = (1/(E*I)).*(-2208.021*x(ii)); % section 2

v3(ii) = (1/(E*I)).*(-2224*(x(ii)-L1)^3)/6; % section 3

v4(ii) = (1/(E*I)).*(-2224*(x(ii)-L2)^3)/6; % section 4

end

disp([v1.', v2.', v3.', v4.'])

0 0 0.0018 0.0219 0.0000 -0.0009 0.0015 0.0200 0.0000 -0.0017 0.0012 0.0183 0.0000 -0.0026 0.0009 0.0167 0.0000 -0.0034 0.0007 0.0152 0.0001 -0.0043 0.0005 0.0137 0.0001 -0.0051 0.0004 0.0124 0.0002 -0.0060 0.0003 0.0112 0.0003 -0.0069 0.0002 0.0100 0.0004 -0.0077 0.0001 0.0089 0.0005 -0.0086 0.0001 0.0079 0.0007 -0.0094 0.0000 0.0070 0.0009 -0.0103 0.0000 0.0062 0.0011 -0.0111 0.0000 0.0054 0.0014 -0.0120 0.0000 0.0047 0.0017 -0.0128 0.0000 0.0040 0.0021 -0.0137 -0.0000 0.0035 0.0025 -0.0146 -0.0000 0.0029 0.0030 -0.0154 -0.0000 0.0025 0.0035 -0.0163 -0.0000 0.0021 0.0041 -0.0171 -0.0001 0.0017 0.0048 -0.0180 -0.0001 0.0014 0.0055 -0.0188 -0.0002 0.0011 0.0063 -0.0197 -0.0002 0.0009 0.0072 -0.0206 -0.0004 0.0007 0.0081 -0.0214 -0.0005 0.0005 0.0091 -0.0223 -0.0007 0.0004 0.0102 -0.0231 -0.0009 0.0002 0.0114 -0.0240 -0.0011 0.0002 0.0126 -0.0248 -0.0014 0.0001 0.0140 -0.0257 -0.0017 0.0001 0.0154 -0.0265 -0.0021 0.0000 0.0170 -0.0274 -0.0025 0.0000 0.0186 -0.0283 -0.0029 0.0000 0.0203 -0.0291 -0.0035 0.0000 0.0222 -0.0300 -0.0040 -0.0000 0.0241 -0.0308 -0.0047 -0.0000 0.0262 -0.0317 -0.0054 -0.0000 0.0284 -0.0325 -0.0062 -0.0000 0.0307 -0.0334 -0.0070 -0.0000 0.0331 -0.0343 -0.0079 -0.0001 0.0357 -0.0351 -0.0089 -0.0001 0.0383 -0.0360 -0.0100 -0.0002 0.0411 -0.0368 -0.0112 -0.0003 0.0441 -0.0377 -0.0124 -0.0004 0.0472 -0.0385 -0.0137 -0.0005 0.0504 -0.0394 -0.0152 -0.0007 0.0537 -0.0402 -0.0167 -0.0009 0.0572 -0.0411 -0.0183 -0.0012 0.0609 -0.0420 -0.0200 -0.0015 0.0647 -0.0428 -0.0219 -0.0018

figure(1)

plot(xd,real(yd),'o-')

axis equal

xlabel('Distance(m)')

ylabel('vertical deformation (m)')

title('Deformation of a beam')

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