用MAPLE解BVP遇到newton iteration not converging

lambeef

具体代码如下：
& A, L) s4 V# F2 A' Wl := 1000*10^(-9);
/ m6 _2 R; ^! ~& d  g- S$ X& gw := 50*10^(-9);
2 u! R6 Y+ l0 F# \/ l% M, V: nk := (1/12)*w^3;
E := 150*10^9;
! z7 P7 ~! j1 n' d$ Ed := 20*10^(-9);
v := 2.3;
electrostatic := 8.854*10^(-12)*v^2*(1/2);
. K( X) R, z  H  I( J2 Tode := diff(y(x), x$4) = electrostatic/((d-y(x))^2/E/k);
$ s1 l- n* i9 |1 P& V  m1 ebcs1 := y(0) = 0, (D(y))(0) = 0, (D(D(y)))(l) = 0, (D(D(D(y))))(l) = 0;
" y. l6 r* e- z8 I- v3 Jansl1 := dsolve({ode, bcs1}, numeric, method = bvp, abserr = 28)
问题是求在静电场作用下，梁的弯曲问题。v是电压,当电压很小时，可以算出结果，但是电压大于1V时出现‘newton iteration not converging’. 想了很长时间做不出来，请各位帮个忙！谢谢！