Моделирование падения закрепленной цепочки — различия между версиями

  1 <br />
  2 window.addEventListener('load',main,false)
  3 function main(){
  4 
  5 	Num = document.getElementById("num").value;
  6     my = document.getElementById("my");
  7     my.innerHTML =Num + " numbers";
  8 	var animation = 0;
  9 	var za = 0;
 10 	var padenie = 0;
 11 	var ctx2 = canvasex2.getContext('2d');
 12 	var cplot = canvasex1.getContext('2d');
 13 	var width = canvasex1.width;
 14     var height = canvasex1.height;
 15 	
 16 	var t_max = 0;
 17 	var q = 0;
 18 	var W=[]; // массив 
 19     var V = []; // массив скоростей
 20 	var c=0;
 21 	una.onclick= function una(){animation = 0;	}
 22   
 23 	start.onclick= function start(){
 24 		
 25 	// Изменяемые параметры
 26 	    var b = document.getElementById("b").value;  // вязкость
 27 		var C = document.getElementById("D").value;  // жесткость пружины
 28 		var N = document.getElementById("num").value;  // количество элементов в цепочке
 29 		var m= document.getElementById("mass").value;  // масса цепочки
 30 
 31 	animation=1;
 32 	za = za + 1;
 33 	// Неизменяемые параметры
 34 	//var N=41; var Mass = 50; var C = 50000; b=0.3;
 35 	var L0 = 10; //равновесное растояние
 36 	var Lenght = (N-1)*L0;
 37     //var m = Mass/N;
 38 	var g = 9.81;
 39 	var rad = 5;
 40 	var eps = 0.9;  
 41 	var voln = 0.1;
 42 	var dt=voln/Math.pow(C/m, 1/2);
 43 	
 44 	
 45 	function Particle(x,y,vx,vy,wx,wy,vxpred,vypred){
 46 		var that=this;
 47 		this.x=x;
 48 		this.y=y;
 49 		this.vx=vx;
 50 		this.vy=vy;
 51 		this.wx=wx;
 52 		this.wy=wy;
 53 		this.vxpred=vxpred;
 54 		this.vypred=vypred;
 55 		
 56 		this.info = function (){
 57 			console.log('Position: ('+that.x+','+that.y+')\nVelocity: ('+that.vx+','+that.vy+')\nAcceleration_y: ('+that.wy+')')
 58 		}
 59 		
 60 		this.move=function(){
 61 			
 62 		}
 63 		
 64 		this.draw = function(){
 65 			ctx2.beginPath();
 66 			ctx2.arc(that.x,that.y,rad,0,2*Math.PI);
 67 			ctx2.fillStyle = '#9999FF';
 68 			ctx2.fill();
 69 		}
 70 	}
 71 	
 72 
 73 if (za==1){	// создание частиц
 74 var particles = [];
 75   
 76   if (N%2==0){
 77 	for(var i=0;i<N;i++){
 78 		var fi= Math.PI/3;
 79 		var dy=0;
 80 		if (i<N/2)
 81 			dy = i*(L0-1)*Math.sin(fi);
 82 		else 
 83 			dy = (N-i-1)*(L0-1)*Math.sin(fi);
 84 		particles.push(
 85 		   new Particle( 400+i*(L0-1)*Math.cos(fi), 50+ dy,  0,  0,  0,  0,  0,  0)
 86 		);
 87 		particles[i].draw();
 88 		}
 89   }
 90 
 91  if (N%2!=0){
 92 	for(var i=0;i<N;i++){
 93 		var fi= Math.PI/4;
 94 		if (i<(N+1)/2)
 95 			var dy = i*(L0-1)*Math.sin(fi);
 96 		else 
 97 			dy = (N-i-1)*(L0-1)*Math.sin(fi);
 98 		particles.push(
 99 		   new Particle( 400+i*(L0-1)*Math.cos(fi), 50+ dy,  0,  0,  0,  0,  0,  0)
100 		);	
101 	    particles[i].draw();
102 	    
103 	}
104   }
105 		
106 }
107 	
108 function phys(){
109 	t_max+=dt;
110 	var Vmax=0;
111 	for(var i=0;i<N;i++){
112 		//particles[i].move();
113 		
114 		if (i!=0 && i!=N-1){
115 			
116 			var rxl = particles[i].x-particles[i-1].x;
117 			var ryl = particles[i].y-particles[i-1].y;
118 			var rl = Math.sqrt(Math.pow(rxl,2)+Math.pow(ryl,2));
119 
120 
121 			var rxr = particles[i].x-particles[i+1].x;
122 			var ryr = particles[i].y-particles[i+1].y;
123 			var rr = Math.sqrt(Math.pow(rxr,2)+Math.pow(ryr,2));
124 			
125 			var Fx = -C*(rl-L0)*rxl/rl/L0 - C*(rr-L0)*rxr/rr/L0;
126 			var Fy = -C*(rl-L0)*ryl/rl/L0 - C*(rr-L0)*ryr/rr/L0;
127 			
128 			particles[i].wx = Fx/m - b* particles[i].vx/m;
129 			particles[i].wy = Fy/m + g - b* particles[i].vy/m;
130 		}
131 		
132 		else if(i==N-1){
133 			if (padenie == 0) W.push (0);
134 			if (padenie == 1){
135 			var rxl = particles[i].x-particles[i-1].x;
136 			var ryl = particles[i].y-particles[i-1].y;
137 			var rl = Math.sqrt(Math.pow(rxl,2)+Math.pow(ryl,2));
138 			
139 			var Fx = -C*(rl-L0)*rxl/rl/L0 ;
140 			var Fy = -C*(rl-L0)*ryl/rl/L0 ;
141 			
142 			particles[i].wx = Fx/m- b* particles[i].vx/m;
143 			particles[i].wy = Fy/m + g- b* particles[i].vy/m;
144 			
145 			W.push (Math.sqrt(Math.pow(particles[N-1].wx,2)+Math.pow(particles[N-1].wy,2)));
146 			console.log(Math.sqrt(Math.pow(particles[N-1].wx,2)+Math.pow(particles[N-1].wy,2)))
147 			}
148 			}
149 	}
150     // явная схема интегрирования, Верле
151 	for (var i=0;i<N;i++){
152 		particles[i].vx = particles[i].vx + particles[i].wx*dt;
153 		particles[i].vy = particles[i].vy + particles[i].wy*dt;
154 		particles[i].x = particles[i].x + particles[i].vx*dt;
155 		particles[i].y = particles[i].y + particles[i].vy*dt;
156 		var v = Math.sqrt(Math.pow(particles[i].vx,2)+Math.pow(particles[i].vy,2));
157 		if (v>Vmax) Vmax=v;
158 	}
159 	if (Vmax < eps){ padenie = 1; b=0.01}
160 	//console.log(Vmax)
161 	}
162 	
163 	
164 	function draw(){
165 		ctx2.clearRect(0,0,800,800);
166 		for(var i=0;i<N;i++){
167 		particles[i].draw();
168 		}
169 		
170 		
171 		cplot.clearRect(0,0,width,height);
172 	   
173 		var W_scale =height/250;
174 		var t_scale= width/t_max;
175 		
176 		cplot.beginPath();
177 			for (var i =0; i<W.length-1; i++){
178 				cplot.moveTo(i*t_scale,height-W[i]*(W_scale)-50);
179 				cplot.lineTo((i+1)*t_scale, height-W[i+1]*(W_scale)-50);
180 					
181 		}
182 		cplot.stroke();	
183 	}
184 	
185 function control(){
186 	if (animation!=0){
187 		phys();
188 		draw();
189 		}
190 	}
191 	setInterval(control,1000*dt);
192 	}
193 	
194 }