finite element to calculate shear force diagram and bending moment diagram deflection of cantilever and distributed load in matlab

You can use the Finite Element Method (FEM) in MATLAB to calculate the shear force diagram, bending moment diagram, and deflection of a cantilever beam under a distributed load. Here is a general overview of the steps involved in this process:

  1. Define the geometry and material properties of the cantilever beam.
  2. Discretize the beam into smaller elements. You can use linear or quadratic elements depending on the accuracy you need.
  3. Apply the distributed load on the beam.
  4. Assemble the global stiffness matrix and load vector.
  5. Apply boundary conditions (fixed end at the base of the cantilever).
  6. Solve the system of equations to obtain nodal displacements.
  7. Calculate the shear force diagram and bending moment diagram using the nodal displacements.
  8. Calculate the deflection of the beam at different points along its length.

You can use MATLAB's built-in functions for FEM analysis such as 'stiffness' and 'displacements' to help with these calculations. Additionally, you may need to use interpolation functions to calculate the shear force, bending moment, and deflection at points between nodes.

Here is a simplified example code snippet to illustrate the process:

main.m
% Define properties
E = 2.1e11; % Young's modulus (Pa)
I = 4.0833e-6; % Moment of inertia (m^4)

% Element properties
L = 3; % Length of the beam (m)
numElements = 10; % Number of elements
elementLength = L / numElements;

% Distributed load
w = 1000; % Distributed load (N/m)

% Initialize global matrices
K = zeros(numElements + 1, numElements + 1);
F = zeros(numElements + 1, 1);

% Assemble stiffness matrix and load vector
for i = 1:numElements
    ke = (E*I/elementLength^3) * [12, 6*elementLength, -12, 6*elementLength; 
                                  6*elementLength, 4*elementLength^2, -6*elementLength, 2*elementLength^2; 
                                  -12, -6*elementLength, 12, -6*elementLength; 
                                  6*elementLength, 2*elementLength^2, -6*elementLength, 4*elementLength^2];
    fe = [w*elementLength/2; w*elementLength^2/12; w*elementLength/2; -w*elementLength^2/12];
    
    % Assemble into global matrices
    K(i:i+1, i:i+1) = K(i:i+1, i:i+1) + ke;
    F(i:i+1) = F(i:i+1) + fe;
end

% Apply boundary conditions
K(1,:) = 0;
K(1,1) = 1;
F(1) = 0;

% Solve for displacements
U = K \ F;

% Calculate shear force diagram, bending moment diagram, and deflection
V = diff(U) .* (E*I/elementLength^3);
M = -E*I*diff(diff(U)) / elementLength^2;
D = U(2:end);

% Plot the diagrams
x = linspace(0, L, numElements+1);
figure;
subplot(3,1,1); plot(x, V); title('Shear Force Diagram');
subplot(3,1,2); plot(x, M); title('Bending Moment Diagram');
subplot(3,1,3); plot(x, D); title('Deflection');

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This is a basic example and you may need to adapt it to your specific requirements and boundary conditions.

Remember that FEM is a powerful method but requires a good understanding of the theory behind it.

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