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{ | ||
"nbformat": 4, | ||
"nbformat_minor": 0, | ||
"metadata": { | ||
"colab": { | ||
"private_outputs": true, | ||
"provenance": [], | ||
"authorship_tag": "ABX9TyNiFdeHqTKjq6Y2q7yQmHLE", | ||
"include_colab_link": true | ||
}, | ||
"kernelspec": { | ||
"name": "python3", | ||
"display_name": "Python 3" | ||
}, | ||
"language_info": { | ||
"name": "python" | ||
} | ||
}, | ||
"cells": [ | ||
{ | ||
"cell_type": "markdown", | ||
"metadata": { | ||
"id": "view-in-github", | ||
"colab_type": "text" | ||
}, | ||
"source": [ | ||
"<a href=\"https://colab.research.google.com/github/GEORMC/Nnumerical_Methods_Course/blob/main/Truss_with_plot.ipynb\" target=\"_parent\"><img src=\"https://colab.research.google.com/assets/colab-badge.svg\" alt=\"Open In Colab\"/></a>" | ||
] | ||
}, | ||
{ | ||
"cell_type": "code", | ||
"execution_count": null, | ||
"metadata": { | ||
"id": "YUsOFx4ipiY3" | ||
}, | ||
"outputs": [], | ||
"source": [ | ||
"import numpy as np\n", | ||
"import matplotlib.pyplot as plt\n", | ||
" # Input data\n", | ||
"coordinates = np.array([\n", | ||
" [0, 0],\n", | ||
" [4, 0],\n", | ||
" [8, 0],\n", | ||
" [4, -6]\n", | ||
"])\n", | ||
"connectivity = np.array([\n", | ||
" [0, 3],\n", | ||
" [1, 3],\n", | ||
" [2, 3]\n", | ||
"])\n", | ||
"E = 100 # Young's Modulus (Pa)\n", | ||
"A = 100 # Cross-sectional area (m^2)\n", | ||
" # Define supports (0 for not supported, 1 for supported)\n", | ||
"supports = np.array([\n", | ||
" [1, 1],\n", | ||
" [1, 1],\n", | ||
" [1, 1],\n", | ||
" [0, 0]\n", | ||
"])\n", | ||
" # Define applied loads (0 for no load, specify direction and value)\n", | ||
"applied_loads = np.array([\n", | ||
" [0, 0],\n", | ||
" [0, 0], # Node 1, applied horizontal load\n", | ||
" [0, 0], # Node 2, applied vertical load\n", | ||
" [100, -100]\n", | ||
"])\n", | ||
" # Create freedom matrix\n", | ||
"num_nodes = len(coordinates)\n", | ||
"num_dofs = 2 * num_nodes\n", | ||
"num_elements=len(connectivity)\n", | ||
"dofs = np.zeros((num_elements, 4), dtype=int)\n", | ||
"NodeDof=np.zeros((num_nodes, 2) , dtype=int)\n", | ||
" # Initialize global stiffness matrix and force vector\n", | ||
"KG = np.zeros((num_dofs, num_dofs))\n", | ||
"kt_global = np.zeros((num_dofs, num_dofs))\n", | ||
"F_global = np.zeros(num_dofs)\n", | ||
" # Calculate Dof Matrix\n", | ||
"for i, (node1, node2) in enumerate(connectivity):\n", | ||
" dofs[i,:] = np.array([2 * node1, 2 * node1 + 1, 2 * node2, 2 * node2 + 1])\n", | ||
" NodeDof[node1,0]=np.array([2 * node1])\n", | ||
" NodeDof[node1,1]=np.array([2 * node1 + 1])\n", | ||
" NodeDof[node2,0]=np.array([ 2 * node2])\n", | ||
" NodeDof[node2,1]=np.array([2* node2+1])\n", | ||
" print(NodeDof)\n", | ||
"# Calculate element lengths and stiffness matrices\n", | ||
"for i, (node1, node2) in enumerate(connectivity):\n", | ||
" x1, y1 = coordinates[node1]\n", | ||
" x2, y2 = coordinates[node2]\n", | ||
" L = np.sqrt((x2 - x1) ** 2 + (y2 - y1) ** 2)\n", | ||
" c = (x2 - x1) / L\n", | ||
" s = (y2 - y1) / L\n", | ||
" k_local = (E * A / L) * np.array([\n", | ||
" [c ** 2, c * s, -c ** 2, -c * s],\n", | ||
" [c * s, s ** 2, -c * s, -s ** 2],\n", | ||
" [-c ** 2, -c * s, c ** 2, c * s],\n", | ||
" [-c * s, -s ** 2, c * s, s ** 2]\n", | ||
" ])\n", | ||
" # Assemble local stiffness matrix into global stiffness matrix\n", | ||
"\n", | ||
" KG[np.ix_(dofs[i,:], dofs[i,:])] += k_local\n", | ||
" # print(k_local)\n", | ||
" # print(np.ix_(dofs[i,:], dofs[i,:]) )\n", | ||
" # print(K_global)\n", | ||
" print(KG)\n", | ||
" kt_global=KG*1\n", | ||
"# Apply boundary conditions and applied loads\n", | ||
"for node in range(num_nodes):\n", | ||
" for i in range(2):\n", | ||
" if supports[node, i] == 1:\n", | ||
" fixed_dof = NodeDof[node,i]\n", | ||
" kt_global[fixed_dof, :] = 0\n", | ||
" kt_global[:, fixed_dof] = 0\n", | ||
" kt_global[fixed_dof, fixed_dof] = 1\n", | ||
" F_global[fixed_dof] = 0\n", | ||
" else:\n", | ||
" applied_force = applied_loads[node, i]\n", | ||
" F_global[2 * node + i] = applied_force\n", | ||
" print(KG)\n", | ||
"# Solve for displacements\n", | ||
"displacement = np.linalg.solve(kt_global, F_global)\n", | ||
"print(KG)\n", | ||
"# Calculate reaction forces\n", | ||
"reaction_forces = np.dot(KG, displacement)\n", | ||
"print(KG)\n", | ||
"print(\"Displacements (mm):\")\n", | ||
"print(displacement * 1000)\n", | ||
"print(\"Reaction Forces (N):\")\n", | ||
"print(reaction_forces)\n", | ||
"\n", | ||
"\n", | ||
"\n", | ||
"\n", | ||
"\n", | ||
"\n", | ||
"\n", | ||
"# Extract coordinates of nodes\n", | ||
"node_x = coordinates[:, 0]\n", | ||
"node_y = coordinates[:, 1]\n", | ||
"\n", | ||
"# Extract connectivity of elements\n", | ||
"fig, ax = plt.subplots()\n", | ||
"\n", | ||
"for i, (node1, node2) in enumerate(connectivity):\n", | ||
" x1, y1 = coordinates[node1]\n", | ||
" x2, y2 = coordinates[node2]\n", | ||
" ax.plot([x1, x2], [y1, y2], 'k-')\n", | ||
"\n", | ||
"# Plot nodes\n", | ||
"ax.plot(node_x, node_y, 'ro')\n", | ||
"\n", | ||
"# Add labels to nodes\n", | ||
"for i in range(len(coordinates)):\n", | ||
" ax.text(coordinates[i][0], coordinates[i][1], str(i))\n", | ||
"\n", | ||
"# Set axis labels and title\n", | ||
"ax.set_xlabel(\"X-axis\")\n", | ||
"ax.set_ylabel(\"Y-axis\")\n", | ||
"ax.set_title(\"Truss Structure\")\n", | ||
"\n", | ||
"# Show the plot\n", | ||
"ax.grid(True)\n", | ||
"ax.axis('equal')\n", | ||
"\n", | ||
"\n", | ||
"# Plot deformed truss\n", | ||
"scale_factor = 10 # Adjust the scale of deformation as needed\n", | ||
"\n", | ||
"deformed_node_x = node_x + displacement[::2] * scale_factor\n", | ||
"deformed_node_y = node_y + displacement[1::2] * scale_factor\n", | ||
"\n", | ||
"#plt.figure() # Create a new figure for the deformed truss\n", | ||
"\n", | ||
"for i, (node1, node2) in enumerate(connectivity):\n", | ||
" x1, y1 = deformed_node_x[node1], deformed_node_y[node1]\n", | ||
" x2, y2 = deformed_node_x[node2], deformed_node_y[node2]\n", | ||
" ax.plot([x1, x2], [y1, y2], 'b-') # Plot deformed elements in blue\n", | ||
"\n", | ||
"ax.plot(deformed_node_x, deformed_node_y, 'ro') # Plot deformed nodes\n", | ||
"\n", | ||
"# Add labels to nodes\n", | ||
"for i in range(len(coordinates)):\n", | ||
" ax.text(deformed_node_x[i], deformed_node_y[i], str(i))\n", | ||
"\n", | ||
"ax.set_xlabel(\"X-axis\")\n", | ||
"ax.set_ylabel(\"Y-axis\")\n", | ||
"ax.set_title(\"Deformed Truss Structure\")\n", | ||
"ax.grid(True)\n", | ||
"ax.axis('equal')\n", | ||
"\n", | ||
"plt.show(block=True)\n" | ||
] | ||
} | ||
] | ||
} |