7.6. 二元颗粒堆积

图 7.7 二元砂颗粒堆积

7.6.1. 基本堆积脚本

import numpy as np
import sys, random

gui = True
sim = None
randSeed = 12345654 #to keep the same config.
random.seed(randSeed)
from dem.core import *
from dem.rtdem import *
from pySudoMath import *
if gui:
    app.core.setAnalysisType(AnalysisType="RTDEM", randSeed = randSeed)
    sim=app.core.sim
else:
    sim = DEMSim()

#define a lattice grid
#R: distance between two neighboring nodes
#num_x: number of nodes along x axis
#num_y: number of nodes along y axis
#num_z: number of nodes along z axis
#return a list of the postions of all nodes
scales = list()
def GridInitial(R,num_x=10,num_y=10,num_z=20, shift=[0,0,0]):#this part is slow, but just for test
    pos = list()
    for k in range(num_z):
        for j in range(num_y):
            for i in range(num_x):
                x = i*R*2.0*1.2+R+shift[0]+random.uniform(0, 0.1*R)
                y = j*R*2.0*1.2+R+shift[1]+random.uniform(0, 0.1*R)
                z = k*R*2.0*1.2+R+shift[2]
                pos.append(Vector3f(x,y,z))
                scales.append(random.uniform(0.6,1.2))
    return pos

7.6.2. 生成颗粒

• 生成大颗粒

psize = 0.09
Num = 5
Num_z = 4
pos = GridInitial(psize,num_x=Num,num_y=Num,num_z=Num_z,shift = [0.0*psize,0.0*psize,1.2*psize])
pnum = len(pos)
ori = list()
for i in range(pnum):
    #ang = random.uniform(0,np.pi)
    #vec = Vector3f()
    ori.append(Quaternionr(-3.1415926/4, Vector3f(0, 1.0, 1.0)))

poly=PolyhedronData()
poly.setPosOri( pos,  ori)
poly.loadSTL("./sand.stl", 0.0015)
poly.computGeometry()
sim.pdata.addObject(poly)

• 生成小颗粒

pos2 = GridInitial(psize*0.2,num_x=Num*5,num_y=Num*5,num_z=15,shift = [0.0*psize,0.0*psize,10.5*psize])
pnum2 = len(pos2)
ori2 = list()
for i in range(pnum2):
    #ang = random.uniform(0,np.pi)
    #vec = Vector3f()
    ori2.append(Quaternionr(-3.1415926/4, Vector3f(0, 1.0, 1.0)))

poly2=PolyhedronData()
poly2.setPosOri( pos2,  ori2)
poly2.loadSTL("./sand.stl", 0.00015*2)#0.001
poly2.computGeometry()
sim.pdata.addObject(poly2)

• 生成容器

box=PolyhedronData()
box.loadSTL("./box.stl", Vector3f(0.6,0.6,0.3), False)
box.setPosition( [Vector3f(0.5,0.5,0.9)])
box.setMovable(False)
sim.pdata.addObject(box)

7.6.3. 其它模型设置

# 大颗粒材料
mat1 = Material()
mat1.density = 2650.0
mat1.kn = 1e4*1e2
mat1.ks = 1e4
mat1.friction = 0.3
sim.pdata.material = mat1 #default material for particles
# 小颗粒材料
mat2 = Material()
mat2.density = 2650.0
mat2.kn = 1e4
mat2.ks = 1e4
mat2.friction = 0.3
# 容器材料
wmat = Material()
wmat.density = 1000.0
wmat.kn = 1e5 #*1e3
wmat.ks = 1e5
wmat.friction = 0.3
sim.pdata.wallMaterial = wmat

sim.integrator.gravity = Vector3f(0,0,-10.0)
sim.integrator.damping = 0.3
sim.integrator.viscousDamping = -0.01

# 将材料赋给颗粒组
poly.material = mat1
poly2.material = mat2

sim.init()

sim.dt = 1e-4