How to fix 'unable to find explicit solution'

clear ;

%beam elements

d=550;Ast=1963;b=300;fck=30;D=600; l=4000;

n1=28; n=200;

syms fc(x)

fc(x)=0.447*fck*(1-((x/0.002)-1)^2);

%stress-strain curve of Fe500 steel

syms ft(x)

ft(x)=piecewise(x<0.00174,2*x*10^5,0.00174<=x,369.6+(x-0.00195)*102857.1429);

ft(x)=piecewise(x<0.00195,ft(x),0.00195<=x,391.3+(x-0.00226)*70000);

ft(x)=piecewise(x<0.00226,ft(x),0.00226<=x,413+(x-0.00277)*42549);

ft(x)=piecewise(x<0.00277,ft(x),0.00277<=x,423.9+(x-0.00312)*31142.857);

ft(x)=piecewise(x<0.00312,ft(x),0.00312<=x,434.8+(x-0.00417)*10380.95233);

ft(x)=piecewise(x<0.00417,ft(x),0.00417<=x,434.8);

M=input('Enter moment value');

syms kd phi

C=int((fc*b/phi),0,phi*kd);

T=Ast*subs(ft,(d-kd)*phi);

m=int(fc*x*b/(phi^2),0,phi*kd);

jd=d-kd+m/C;

eqn=(C*jd*10^(-6)==M);

eqn2=(C==T);

[a,b]=solve(eqn,eqn2,kd,phi);

[Star Strider]

I can make no sense out of the second throough fifth piecewise statements, and I suspect the Symbolic Math Toolbox is not able to either.

Please describe what you want to do in them.

Answer 1

[Pankhuri Kasliwal]

This issue is related to the new MuPAD symbolic engine which replaced Maple. MuPAD does not make the same assumptions as Maple.

As a workaround, use the 'IgnoreSpecialCases' option in MuPAD to return results more like those returned by Maple.