写一个非常规态基近场动力学计算复合裂纹的python代码

非常规态基近场动力学（Peridynamics）是一种基于无穷远扰动的连续介质力学模型，可以用于模拟材料的断裂行为。以下是一个用Python编写的基于非常规态基近场动力学模型计算复合裂纹的代码：

import numpy as np
import matplotlib.pyplot as plt

# 定义参数
dx = 0.01
dt = 0.01
L = 1
T = 1
E = 1
nu = 0.3
Gc = 0.1
omega = 0.5
r_c = 0.1
r_a = 0.2
K = E/(3*(1-2*nu))

# 定义函数
def w(x):
    return 1 - x*x

def K1(x):
    return K*(1 - 2*nu)*w(x)

def K2(x):
    return K*nu*w(x)

def K3(x):
    return K*(1 - nu)*w(x)

def d(x):
    return 2*Gc*(1 - omega)*(1 - x/r_c)**2

def psi(x):
    if x > r_a:
        return 0
    else:
        return (1 - x/r_a)**2

# 初始化网格
N = int(L/dx)
U = np.zeros(N)
V = np.zeros(N)
R = np.zeros(N)
H = np.zeros(N)
D = np.zeros(N)

# 定义边界条件
U[0] = 0
U[-1] = 0

# 定义初始断裂
R[N//2] = 1

# 进行时间循环
for t in range(int(T/dt)):
    # 计算应力和力
    for i in range(1, N-1):
        F = 0
        for j in range(1, N-1):
            if i != j:
                x = abs(i-j)*dx
                Kx = K1(x) + K2(x) + K3(x)
                F += Kx*(U[j] - U[i])
                if R[j] > 0:
                    F += d(x)*psi(R[j])*np.sign(U[j] - U[i])
        H[i] = F
        S = 0
        for j in range(1, N-1):
            if i != j:
                x = abs(i-j)*dx
                Kx = K1(x) + K2(x) + K3(x)
                S += Kx*(R[j]/(dx*dx) + psi(R[j])*np.sign(U[j] - U[i]))
        D[i] = S

    # 更新位移和裂缝
    for i in range(1, N-1):
        V[i] += (H[i] - D[i])*dt/(rho*dx)
        U[i] += V[i]*dt
        R[i] += D[i]*dt

    # 绘制图像
    plt.clf()
    plt.plot(np.linspace(0, L, N), U)
    plt.plot(np.linspace(0, L, N), R)
    plt.xlim(0, L)
    plt.ylim(-0.1, 1.1)
    plt.title('Time: {:.2f}'.format((t+1)*dt))
    plt.xlabel('Position')
    plt.ylabel('Displacement/Crack')
    plt.legend(['Displacement', 'Crack'])
    plt.pause(0.01)