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麻烦大家帮忙看下mathematical编的程序，不知道哪里出错了

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发表于 2014-7-7 17:15 |只看该作者 |倒序浏览

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本帖最后由游龙游龙于 2014-7-8 14:45 编辑

麻烦大家帮忙看下这个程序，不知道哪里出错了，小弟是刚入门，请高手指教
行列式求不出，画图找不到根
(*定义材料常数*)
Subscript[\[Nu], TL] = 0.25;
Subscript[EE, L] = 53.8*10^9;(*L方向的弹性模量*)
Subscript[EE, T] = 17.93*10^9;(*T方向的弹性模量*)
Subscript[G, LT] = 8.96*10^9;(*LT方向的剪切模量*)
Subscript[\[Nu], LT] =
  Subscript[\[Nu], TL]*Subscript[EE, L]/Subscript[EE, T];
\[Mu] = 1 - Subscript[\[Nu], LT]*Subscript[\[Nu], TL];
Subscript[C, L] = Subscript[EE, L]/\[Mu];
Subscript[C, S] = Subscript[\[Nu], LT]*Subscript[EE, T]/\[Mu];
Subscript[C, T] = Subscript[EE, T]/\[Mu];
Subscript[C, LT] = Subscript[G, LT];
(*脱层几何参数*)
\[Rho] = 1600;(*脱层密度*)
c = 0.06;(*阻尼*)
t = 0.01;(*t每层厚度*)
h = 0.05;(*h为梁总厚度*)
l = 1;(*为梁总的长度*)
Subscript[l, 1] = 0.3;(*为梁1区的长度*)
Subscript[l, 2] = 0.3;(*为梁2区的长度*)
Subscript[l, 3] = 0.4;(*为梁3区的长度*)
Subscript[l, 4] = 0.4;(*为梁4区的长度*)
nn1 = h/t;(*nn1为总铺层厚度*)
nn2 = 2.0;(*为上子铺层层数*)
nn3 = h/t - nn2;(*下子铺层层数*)
Subscript[h, 3] = t*nn2;(*梁的上部子厚度*)
Subscript[h, 4] = h - Subscript[h, 3];(*梁的下部子厚度*)
Subscript[h, 1] = h;(*梁1区的厚度*)
Subscript[h, 2] = h;(*梁2区的厚度*)
(*求各单层刚度*)
agk = {0 Pi/180, 90 Pi/180, 0 Pi/180, 90 Pi/180, 0 Pi/180};(*列表各铺层角度*)

ck = Cos[agk];(*列表求各铺层角度余弦*)
sk = Sin[agk];(*列表求各铺层角度正弦*)
s11k = ck^4*Subscript[C, L] + 2 ck^2*sk^2*Subscript[C, S] +
         sk^4*Subscript[C, T] +
4 ck^2*sk^2*Subscript[C, LT];(*求各区刚度*)
A11 = \!\(
\*UnderoverscriptBox[\(\[Sum]\), \(k =
1\), \(nn1\)]\((s11k[\([\)\(k\)\(]\)]*t)\)\)(*一区拉伸刚度*)
A21 = A11
A31 = (\!\(
\*UnderoverscriptBox[\(\[Sum]\), \(k =
   1\), \(nn2\)]\(\((s11k[\([\)\(k\)\(]\)])\)*t\)\))(*三区拉伸刚度*)
A41 = (\!\(
\*UnderoverscriptBox[\(\[Sum]\), \(k =
   nn2 + 1\), \(nn1\)]\(\((s11k[\([\)\(k\)\(]\)])\)*t\)\))(*四区拉伸刚度*)

Print["A21=A11;D21=D11"];(*二区拉伸刚度、弯曲刚度*)
D11 = \!\(
\*UnderoverscriptBox[\(\[Sum]\), \(k =
1\), \(nn1\)]\((s11k[\([\)\(k\)\(]\)]*
\*FractionBox[\(t^3\), \(12\)])\)\)
D21 = D11
D31 = \!\(
\*UnderoverscriptBox[\(\[Sum]\), \(k =
1\), \(nn2\)]\((s11k[\([\)\(k\)\(]\)]*
\*FractionBox[\(t^3\), \(12\)])\)\)(*三区弯曲刚度*)
D41 = \!\(
\*UnderoverscriptBox[\(\[Sum]\), \(k =
nn2 + 1\), \(nn1\)]\((s11k[\([\)\(k\)\(]\)]*
\*FractionBox[\(t^3\), \(12\)])\)\)(*四区弯曲刚度*)
k1 = Subscript[l, 1]/l; k2 = Subscript[l, 2]/l; k3 = Subscript[l, \
3]/l; k4 = Subscript[l, 4]/l; \[Alpha] = h/l;
a1 = (\[Alpha]*k1)/(DD1*(\[Beta]1)^3); a2 = (\[Alpha]*k2)/(
DD2*(\[Beta]2)^3); a3 = (\[Alpha]*k3)/(
DD3*(\[Beta]3)^3); a4 = (\[Alpha]*k4)/(DD4*(\[Beta]4)^3);
\[Beta]1 = h/Subscript[l, 1]; \[Beta]2 = h/Subscript[l, 2]; \[Beta]3 \
= h/Subscript[l, 3]; \[Beta]4 = h/Subscript[l, 4];
b1 = Subscript[l, 1]/Subscript[l, 3]; b2 = Subscript[l, \
1]/Subscript[l, 4]; b3 = Subscript[l, 2]/Subscript[l, 3]; b4 = \
Subscript[l, 2]/Subscript[l, 4];
DD1 = D11/(A11*h^2); DD2 = D21/(A11*h^2); DD3 = D31/(A11*h^2);
DD4 = D41/(A11*h^2);
r11 = Power[a1*\[Omega]^2, (4)^-1]; r12 = Power[
a2*\[Omega]^2, (4)^-1]; r13 = Power[
a3*\[Omega]^2, (4)^-1]; r14 = Power[a4*\[Omega]^2, (4)^-1];
BB = {{1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0},
  {0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0},
  {0, Cosh[r12], 0, 0, 0, Sinh[r12], 0, 0, 0, Cos[r12], 0, 0, 0,
Sin[r12], 0, 0},
  {0, Sinh[r12], 0, 0, 0, Cosh[r12], 0, 0, 0, -Sin[r12], 0, 0, 0,
Cos[r12], 0, 0},
  {-(r11)^2*DD1*(\[Beta]1)^2*Cosh[r11],
0, (r13)^2*DD3*(\[Beta]3)^2, (r14)^2*DD4*(\[Beta]4)^2,
-(r11)^2*DD1*(\[Beta]1)^2*Sinh[r11], 0, 0,
0, (r11)^2*DD1*(\[Beta]1)^2*Cos[r11],
0, -(r13)^2*DD3*(\[Beta]3)^2, -(r14)^2*DD4*(\[Beta]4)^2, (r11)^2*
DD1*(\[Beta]1)^2*Sin[r11], 0, 0, 0},
  {-(r11)^3*DD1*(\[Beta]1)^3*Sinh[r11], 0, 0,
0, -(r11)^3*DD1*(\[Beta]1)^3*Cosh[r11],
0, (r13)^3*DD3*(\[Beta]3)^3, (r14)^3*DD4*(\[Beta]4)^3, -(r11)^3*
DD1*(\[Beta]1)^3*Sin[r11], 0, 0, 0,
(r11)^3*DD1*(\[Beta]1)^3*Cos[r11],
0, -(r13)^3*DD3*(\[Beta]3)^3, -(r14)^3*DD4*(\[Beta]4)^3},
  {0, -(r12)^2*DD2*(\[Beta]2)^2, (r13)^2*DD3*(\[Beta]3)^2*
Cosh[r13], (r14)^2*DD4*(\[Beta]4)^2*Cosh[r14],
0, 0, (r13)^2*DD3*(\[Beta]3)^2*Sinh[r13], (r14)^2*DD4*(\[Beta]4)^2*
Sinh[r14], 0, (r12)^2*DD2*(\[Beta]2)^2,
-(r13)^2*DD3*(\[Beta]3)^2*Cos[r13], -(r14)^2*DD4*(\[Beta]4)^2*
Cos[r14], 0, 0,
-(r13)^2*DD3*(\[Beta]3)^2*Sin[r13], -(r14)^2*DD4*(\[Beta]4)^2*
Sin[r14]},
  {0, 0, (r13)^3*DD3*(\[Beta]3)^3*Sinh[r13], (r14)^3*DD4*(\[Beta]4)^3*
Sinh[r14], 0, -(r12)^3*DD2*(\[Beta]2)^3,
(r13)^3*DD3*(\[Beta]3)^3*Cosh[r13], (r14)^3*DD4*(\[Beta]4)^3*
Cosh[r14], 0, 0, (r13)^3*DD3*(\[Beta]3)^3*Sin[r13],
(r14)^3*DD4*(\[Beta]4)^3*Sin[r14],
0, (r12)^3*DD2*(\[Beta]2)^3, -(r13)^3*DD3*(\[Beta]3)^3*Cos[r13],
-(r14)^3*DD4*(\[Beta]4)^3*Cos[r14]},
  {Cosh[r11], 0, -1, 0, Sinh[r11], 0, 0, 0, Cos[r11], 0, -1, 0,
Sin[r11], 0, 0, 0},
  {r11*Sinh[r11], 0, 0, 0, r11*Cosh[r11], 0, -r13*b1,
0, -r11*Sin[r11], 0, 0, 0, r11*Cos[r11],
0, -r13*b1},
  {Cosh[r11], 0, 0, -1, Sinh[r11], 0, 0, 0, Cos[r11], 0, 0, -1,
Sin[r11], 0, 0, 0},
  {r11*Sinh[r11], 0, 0, 0, r11*Cosh[r11], 0,
0, -r14*b2, -r11*Sin[r11], 0, 0, 0, r11*Cos[r11],
0, 0, -r14*b2},
  {0, 1, -Cosh[r13], 0, 0, 0, -Sinh[r13], 0, 0, 1, -Cos[r13], 0, 0, 0,
0, -Sin[r13]},
  {0, 0, -r13*b3*Sinh[r13], 0, 0, r12, -r13*b3*Cosh[r13], 0, 0, 0,
r13*b3*Sin[r13],
0, 0, r12, -r13*b3*Cos[r13], 0},
  {0, 1, 0, -Cosh[r14], 0, 0, 0, -Sinh[r14], 0, 1, 0, -Cos[r14], 0, 0,
0, -Sin[r14]},
  {0, 0, 0, -r14*b4*Sinh[r14], 0, r12, 0, -r14*b4*Cosh[r14], 0, 0, 0,
r14*b4*Sin[r14],
0, r12, 0, -r14*b4*Cos[r14]}}
aa1 = Det[BB]
Plot[aa1, {\[Omega], -10, 10}]
ss = FindRoot[aa1 == 0, {\[Omega], 2}][[1]]

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