Plot a Honeycomb Contour

I need to create the contour of an irregular Honeycomb with Nx x Ny unit cells and wall thickness th. All I need are the x,y coordinates of the endpoints describing the contour and their connectivity.

So far I have the x,y coordinates of the endpoints describing the lines in the center of the Honeycomb and their corresponding connectivity. I modified the code found in Drawing honey comb structure by matlab

Any help is very much appreciated!

clc
close all
clear
format long g
%% Control Parameters
L = 7;
Nx = 4; % Number of unit cells in the horizontal direction
Ny = 2; % Number of pair of unit cells in the vertical direction
Th = 2; % Thickness of the walls
%% Generating Honeycomb Topology
[nodes,elems] = CreateHoneycombTopology(L,Nx,Ny);
nodes(30,2:3) = [nodes(30,2)+2,nodes(30,3)-1]; % Adding localized imperfection
%%
r = Th/(2*sind(60));
znodes = [];
zelems = [];
nid = 0;
nel = 0;

angles = [];

for cont1 = 1:size(elems,1)
    x1 = nodes(elems(cont1,2),2);
    x2 = nodes(elems(cont1,3),2);
    y1 = nodes(elems(cont1,2),3);
    y2 = nodes(elems(cont1,3),3);
    dx = x2-x1;
    dy = y2-y1;
    phi = atan2d(dy,dx);
    angles = [angles;phi];
    nx1 = x1+r*cosd(phi-60);
    ny1 = y1+r*sind(phi-60);
    mx1 = x1+r*cosd(phi+60);
    my1 = y1+r*sind(phi+60);
    nx2 = x2+r*cosd(phi+240);
    ny2 = y2+r*sind(phi+240);
    mx2 = x2+r*cosd(phi+120);
    my2 = y2+r*sind(phi+120);
    
    nid = nid+1;
    znodes = [znodes;nid,nx1,ny1,nx2,ny2,mx1,my1,mx2,my2];
end
%% 
% figure
hold on
for cont1 = 1:size(znodes,1)
    plot(znodes(cont1,[2,4]),znodes(cont1,[3,5]),'b-')
    plot(znodes(cont1,[6,8]),znodes(cont1,[7,9]),'m--')
end
axis equal
axis padded

%% Function to create Honeycomb Topology
function [nodes,elems] = CreateHoneycombTopology(L,Nx,Ny)
%% Generating Walls
X1 = [0:Ny].*3;
X2 = X1+1;
X3 = [-0.5:3:8.5];
X3 = [0:Ny+1].*3-0.5;
X4 = X2+0.5;
nodes = [];
elems = [];
nid = 0;
nel = 0;
for m=0:Nx-1
    gap=sqrt(3);
    step=[m m]*sqrt(3);
    for n=1:length(X1)-1
        [nodes,elems,nid,nel] = UpdateArrays(nodes,elems,nid,nel,[0 0]*gap+step    ,[X1(n) X2(n)]);
        [nodes,elems,nid,nel] = UpdateArrays(nodes,elems,nid,nel,[0.5 0.5]*gap+step,[X3(n+1) X4(n)]);
        [nodes,elems,nid,nel] = UpdateArrays(nodes,elems,nid,nel,[0 0.5]*gap+step  ,[X2(n) X4(n)]);
        [nodes,elems,nid,nel] = UpdateArrays(nodes,elems,nid,nel,[0 0.5]*gap+step  ,[X1(n+1) X3(n+1)]);
        [nodes,elems,nid,nel] = UpdateArrays(nodes,elems,nid,nel,[0.5 1]*gap+step  ,[X3(n+1) X1(n+1)]);
        [nodes,elems,nid,nel] = UpdateArrays(nodes,elems,nid,nel,[0.5 1]*gap+step  ,[X4(n) X2(n)]);
    end
end
for n=1:length(X1)-1
    [nodes,elems,nid,nel] = UpdateArrays(nodes,elems,nid,nel,[1 1]*gap+step,[X1(n) X2(n)]);
end
%% Removing repeated nodes
temp = unique(nodes(:,2:3),'rows');
temp = [[1:size(temp,1)].',temp];
for cont1 = 1:size(elems,1)
    id = temp(ismember(temp(:,2:3),nodes(elems(cont1,2),2:3),'rows'),1);
    elems(cont1,2) = id;
    id = temp(ismember(temp(:,2:3),nodes(elems(cont1,3),2:3),'rows'),1);
    elems(cont1,3) = id;
end
nodes = temp;
%% Scaling nodes
nodes(:,2:3) = nodes(:,2:3).*L;
%% Plotting final geometry
if true
    figure
    hold on
    for cont1 = 1:size(elems,1)
        plot(nodes(elems(cont1,2:3),2),nodes(elems(cont1,2:3),3),'k:')
        axis equal
    end
    plot(nodes(:,2),nodes(:,3),'ro')
end
end
%% function to add wall to arrays of nodes and elements
function [nodes,elems,nid,nel] = UpdateArrays(nodes,elems,nid,nel,x,y)
x1 = x(1);
x2 = x(2);
y1 = y(1);
y2 = y(2);
nel = nel+1;
nid = nid+1;
nodes = [nodes;nid,x1,y1];
elems = [elems;nel,nid,nid+1];
nid = nid+1;
nodes = [nodes;nid,x2,y2];
end

Answer 1

[Vandit]

Hi,

Kindly add below code snippet to generate the contour of the honeycomb structure and plot it on top of the original honeycomb plot :

%% Generate Contour
contour_x = [];
contour_y = [];
connectivity = [];


for cont1 = 1:size(znodes, 1) 
    contour_x = [contour_x; znodes(cont1, [2, 4, 6, 8])]; 
    contour_y = [contour_y; znodes(cont1, [3, 5, 7, 9])];   
    connectivity = [connectivity; [cont1, cont1, cont1, cont1]];   
end

%% Plotting
figure
hold on


% Plot original honeycomb structure
for cont1 = 1:size(elems, 1)   
    plot(nodes(elems(cont1, 2:3), 2), nodes(elems(cont1, 2:3), 3), 'k:')    
end


% Plot contour
for cont1 = 1:size(contour_x, 1)  
    plot(contour_x(cont1, :), contour_y(cont1, :), 'r-')    
end

The above mentioned code snippet generates a contour plot by extracting the x and y coordinates from the 'znodes' matrix, which represents modified nodes of a honeycomb structure. The extracted coordinates are stored in 'contour_x' and 'contour_y' matrices, respectively.Then, the code plots the original honeycomb structure as a black dotted line by iterating over the 'elems' matrix. Finally, the code plots the contour by iterating over the ‘contour_x’ matrix. The x and y coordinates of the contour points are extracted and plotted as a red solid line.

The output of the above code snippet is attached below for your reference.

Hope this helps.

Thankyou