Chuyên đề 1

 public static PHANTU TinhKe(PHANTU P1) {
            P1.Ke1 = new Matrix(4,4);
            for (int i = 0; i < 4; i++)
            {
                for (int j = 0; j < 4; j++)
                {
                    P1.Ke1.Matran1[i, j] = 0;
                }
            }
            P1.Ke1.Matran1[0, 0] = P1.MC.VL1.E1 * P1.MC.F1 / P1.L;
            P1.Ke1.Matran1[0, 2] = -P1.Ke1.Matran1[0, 0];
            P1.Ke1.Matran1[2, 0] = -P1.Ke1.Matran1[0, 0];
            P1.Ke1.Matran1[2, 2] = P1.Ke1.Matran1[0, 0];

            P1.T1 = new Matrix(4, 4);
            Matrix Te = new Matrix(2, 2);
            Te.Matran1[0, 0] = P1.cosalpha;
            Te.Matran1[0, 1] = P1.sinalpha;
            Te.Matran1[1, 0] = -P1.sinalpha;
            Te.Matran1[1, 1] = P1.cosalpha;
            for (int i = 0; i < 4; i++)
            {
                for (int j  = 0; j  < 4; j ++)
                {
                    P1.T1.Matran1[i, j] = 0;
                }
            }
            for (int i = 0; i < 2; i++)
            {
                for (int j = 0; j < 2; j++)
                {
                    P1.T1.Matran1[i, j] = Te.Matran1[i, j];
                    P1.T1.Matran1[2 + i, 2 + j] = Te.Matran1[i, j];
                }
            }

            return P1;
        }

 public static PHANTU TinhFe(PHANTU P1) {//Tính Fe
            double P = P1.MC1.VL1.Gama * P1.MC1.B * P1.MC1.H * P1.L1;//P - trong luong ban than
            P1.Ue = new Matrix(4, 1);
            P1.Fe = new Matrix(4, 1);
            P1.Fe.Matran1[0, 0] = 0;
            P1.Fe.Matran1[1, 0] = P / 2;
            P1.Fe.Matran1[2, 0] = 0;
            P1.Fe.Matran1[3, 0] = - P / 2;

            for (int i = 0; i < P1.PT1.Px.Length; i++)
            {
                P1.Fe.Matran1[0, 0] += (P1.L - P1.PT1.Px[i].XI1) * P1.PT1.Px[i].PI1 / P1.L;
                P1.Fe.Matran1[2,0] += P1.PT1.Px[i].XI1 *P1.PT1.Px[i].PI1 / P1.L;
            }
            for (int i = 0; i < P1.PT1.Py.Length; i++)
            {
                P1.Fe.Matran1[1, 0] += (P1.L - P1.PT1.Py[i].XI1) * P1.PT1.Py[i].PI1 / P1.L;
                P1.Fe.Matran1[3, 0] += P1.PT1.Py[i].XI1 * P1.PT1.Py[i].PI1 / P1.L;
            }
            for (int i = 0; i < P1.PT1.Qx.Length; i++)
            {
                double VA = P1.PT1.Qx[i].Q1 * P1.PT1.Qx[i].B * (P1.L - P1.PT1.Qx[i].A - P1.PT1.Qx[i].B / 2) + (P1.PT1.Qx[i].Q2 - P1.PT1.Qx[i].Q1) * (P1.L - P1.PT1.Qx[i].A - 2 * P1.PT1.Qx[i].B / 3) * P1.PT1.Qx[i].B / (2 * P1.L);
                double VB = (P1.PT1.Qx[i].Q1 + P1.PT1.Qx[i].Q2) * P1.PT1.Qx[i].B / 2 - VA;
                P1.Fe.Matran1[0, 0] += VA;
                P1.Fe.Matran1[2, 0] += VB;
            }
            for (int i = 0; i < P1.PT1.Qy.Length; i++)
            {
                double VA = P1.PT1.Qy[i].Q1 * P1.PT1.Qy[i].B * (P1.L - P1.PT1.Qy[i].A - P1.PT1.Qy[i].B / 2) + (P1.PT1.Qy[i].Q2 - P1.PT1.Qy[i].Q1) * (P1.L - P1.PT1.Qy[i].A - 2 * P1.PT1.Qy[i].B / 3) * P1.PT1.Qy[i].B / (2 * P1.L);
                double VB = (P1.PT1.Qy[i].Q1 + P1.PT1.Qy[i].Q2) * P1.PT1.Qy[i].B / 2 - VA;
                P1.Fe.Matran1[1, 0] += VA;
                P1.Fe.Matran1[3, 0] += VB;
            }
            return P1;
        }

public static Matrix AddKe2K(PHANTU P1, Matrix K)
        {//Đưa Ke vào K
            int n = K.Row;
            Matrix Ke = Matrix.Copy(P1.Ke1);
            Ke = Matrix.M_Mul(P1.T1, P1.Ke1);
            Matrix TT = Matrix.Trans(P1.T1);
            Ke = Matrix.M_Mul(Ke, TT);
            int a = 0;
            for (int i = 0; i < n; i++)

                if (i == 2 * P1.I.Ten1 || i == 2 * P1.I.Ten1 + 1 || i == P1.K.Ten1 * 2 || i == P1.k.Ten1 * 2 + 1)
                {
                    int b = 0;
                    for (int j = 0; j < n; j++)
                    {
                        if (j == 2 * P1.I.Ten1 || j == 2 * P1.I.Ten1 + 1 || j == P1.K.Ten1 * 2 || j == P1.k.Ten1 * 2 + 1)
                        {
                            K.Matran1[i, j] += Ke.Matran1[a, b];
                            b++;
                        }
                    }
                    a++;
                }
            return K;
        }

public static Matrix AddFe2F(PHANTU P1, Matrix F) {//Đưa Fe vào F
            int i = P1.i.Ten1;
            int k = P1.k.Ten1;
            Matrix Fe = Matrix.Copy(P1.Fe);
            Fe = Matrix.M_Mul( P1.T1,Fe);
            F.Matran1[2 * i , 0] += Fe.Matran1[0, 0];
            F.Matran1[2 * i +1, 0] += Fe.Matran1[1, 0];
            F.Matran1[2 * k  , 0] += Fe.Matran1[2, 0];
            F.Matran1[2 * k +1, 0] += Fe.Matran1[3, 0];
            return F;
        }

public static PHANTU TakeUeFromU(PHANTU P1, Matrix U) {
            //Lay Ue ra tu U
            int i = P1.i.Ten1;
            int k = P1.k.Ten1;
            Matrix Ue = Matrix.Copy(P1.Ue);
            Ue.Matran1[0, 0] = U.Matran1[2 * i , 0];
            Ue.Matran1[1, 0] = U.Matran1[2 * i + 1 , 0];
            Ue.Matran1[2, 0] = U.Matran1[2 * k , 0];
            Ue.Matran1[3, 0] = U.Matran1[2 * k + 1 , 0];

            Matrix TT = Matrix.Trans(P1.T1);
            Ue = Matrix.M_Mul(TT, Ue);

            P1.Ue = Ue;
            return P1;
        }