feat: add double pendulum simulation (#256)

app/(core)/data/chapters.js

@@ -97,6 +97,14 @@ const chapters = [
     tags: [TAGS.MEDIUM, TAGS.DYNAMICS, TAGS.SPRINGS, TAGS.OSCILLATIONS],
     icon: "/icons/spring.png",
   },
+  {
+    id: 12,
+    name: "Double Pendulum",
+    desc: "Simulate a double pendulum and explore chaotic motion. Watch how small changes in initial conditions lead to completely different trajectories — a classic example of chaos theory.",
+    link: "/simulations/DoublePendulum",
+    tags: [TAGS.ADVANCED, TAGS.DYNAMICS, TAGS.OSCILLATIONS, TAGS.ENERGY],
+    icon: "/icons/pendulam.png",
+  },
   {
     id: 0,
     name: "Browser Performance & Stress Test",

app/(core)/data/configs/DoublePendulum.js

@@ -0,0 +1,118 @@
+// app/(core)/data/configs/DoublePendulum.js
+
+export const INITIAL_INPUTS = {
+  length1: 2,
+  length2: 2,
+  mass1: 1,
+  mass2: 1,
+  gravity: 9.81,
+  damping: 0,
+  initialAngle1: 90,
+  initialAngle2: 90,
+  trailEnabled: true,
+  bob1Color: "#3b82f6",
+  bob2Color: "#ef4444",
+  ropeColor: "#9ca3af",
+};
+
+export const INPUT_FIELDS = [
+  {
+    name: "length1",
+    label: "Length 1 (m)",
+    type: "number",
+    min: 0.5,
+    max: 4,
+    step: 0.1,
+  },
+  {
+    name: "length2",
+    label: "Length 2 (m)",
+    type: "number",
+    min: 0.5,
+    max: 4,
+    step: 0.1,
+  },
+  {
+    name: "mass1",
+    label: "Mass 1 (kg)",
+    type: "number",
+    min: 0.1,
+    max: 5,
+    step: 0.1,
+  },
+  {
+    name: "mass2",
+    label: "Mass 2 (kg)",
+    type: "number",
+    min: 0.1,
+    max: 5,
+    step: 0.1,
+  },
+  {
+    name: "gravity",
+    label: "Gravity (m/s²)",
+    type: "number",
+    min: 1,
+    max: 20,
+    step: 0.1,
+  },
+  {
+    name: "damping",
+    label: "Damping",
+    type: "number",
+    min: 0,
+    max: 1,
+    step: 0.01,
+  },
+  {
+    name: "initialAngle1",
+    label: "Initial Angle 1 (°)",
+    type: "number",
+    min: -180,
+    max: 180,
+    step: 1,
+  },
+  {
+    name: "initialAngle2",
+    label: "Initial Angle 2 (°)",
+    type: "number",
+    min: -180,
+    max: 180,
+    step: 1,
+  },
+  {
+    name: "trailEnabled",
+    label: "Show Trail",
+    type: "checkbox",
+  },
+  {
+    name: "bob1Color",
+    label: "Bob 1 Color",
+    type: "color",
+  },
+  {
+    name: "bob2Color",
+    label: "Bob 2 Color",
+    type: "color",
+  },
+  {
+    name: "ropeColor",
+    label: "Rope Color",
+    type: "color",
+  },
+];
+
+export const SimInfoMapper = (bodyState) => {
+  const angle1 = (bodyState.angle1 * 180) / Math.PI;
+  const angle2 = (bodyState.angle2 * 180) / Math.PI;
+
+  return {
+    "Angle 1": `${angle1.toFixed(1)}°`,
+    "Angle 2": `${angle2.toFixed(1)}°`,
+    "Angular Vel 1": `${bodyState.angularVel1.toFixed(2)} rad/s`,
+    "Angular Vel 2": `${bodyState.angularVel2.toFixed(2)} rad/s`,
+    KE: `${bodyState.kineticEnergy.toFixed(2)} J`,
+    PE: `${bodyState.potentialEnergy.toFixed(2)} J`,
+    "Total E": `${(bodyState.kineticEnergy + bodyState.potentialEnergy).toFixed(2)} J`,
+  };
+};

routes.js

@@ -63,4 +63,10 @@ export const routes = [
     changefreq: "weekly",
     priority: 0.7,
   },
+  {
+    path: "/simulations/DoublePendulum",
+    component: "DoublePendulum",
+    changefreq: "weekly",
+    priority: 0.7,
+  },
 ];