Section Modulus Calculator

import math

def section_modulus(shape, **dims):
    """
    Calculate elastic section modulus S = I/c.

    shape: 'rectangle', 'circle', 'hollow', 'custom'
    dims: corresponding dimensions in mm
    """

    if shape == 'rectangle':
        b, h = dims['b'], dims['h']
        I = (b * h**3) / 12
        c = h / 2
    elif shape == 'circle':
        d = dims['d']
        I = (math.pi * d**4) / 64
        c = d / 2
    elif shape == 'hollow':
        D, d = dims['D'], dims['d']
        I = (math.pi / 64) * (D**4 - d**4)
        c = D / 2
    elif shape == 'custom':
        I, c = dims['I'], dims['c']
    else:
        raise ValueError("Unknown shape")

    S = I / c
    return {"I_mm4": I, "c_mm": c, "S_mm3": S}


# Example (rectangle)
results = section_modulus('rectangle', b=100, h=200)
print(results)

function results = section_modulus(shape, dims)
    % Calculate elastic section modulus S = I/c
    % shape: 'rectangle', 'circle', 'hollow', 'custom'

    if strcmp(shape, 'rectangle')
        b = dims.b; h = dims.h;
        I = (b * h^3) / 12;
        c = h / 2;
    elseif strcmp(shape, 'circle')
        d = dims.d;
        I = (pi * d^4) / 64;
        c = d / 2;
    elseif strcmp(shape, 'hollow')
        D = dims.D; d = dims.d;
        I = (pi / 64) * (D^4 - d^4);
        c = D / 2;
    elseif strcmp(shape, 'custom')
        I = dims.I; c = dims.c;
    else
        error('Unknown shape');
    end

    results.I = I;
    results.c = c;
    results.S = I / c;
end

% Example
dims.b = 100; dims.h = 200;
r = section_modulus('rectangle', dims);
disp(r);