Question: How I can perform some substitutions by using MAPLE commands such as either "algsubs" or any other commands or applying any possible method In MAPLE?

Hi

I have an expression as the following:

exp1:=E(z)*(diff(t(r), r))/(1-nu(z)^2)+E(z)*nu(z)*t(r)/((1-nu(z)^2)*r)+(E(z)*z/(1-nu(z)^2)-(4/3)*E(z)*z^3/(h^2*(1-nu(z)^2)))*(diff(y(r), r))+(E(z)*nu(z)*z/(1-nu(z)^2)-(4/3)*E(z)*nu(z)*z^3/(h^2*(1-nu(z)^2)))*y(r)/r-(4/3)*E(z)*z^3*(diff(p(r), r, r))/(h^2*(1-nu(z)^2))-(4/3)*E(z)*nu(z)*z^3*(diff(p(r), r))/(h^2*(1-nu(z)^2)*r);

I want to replace the following parameter instead of coefficients of t(r), y(r), p(r) and their derivatives as the following:

E(z)/(1-nu(z)^2) ----> A11

E(z)*nu(z)/(1-nu(z)^2) -----> A12

E(z)*(z)/(1-nu(z)^2) -----> B11

E(z)*(-4/3*z^3/h^2)/(1-nu(z)^2) ------> D11

E(z)*nu(z)*(z)/((1-nu(z)^2)) -----> B12

E(z)*nu(z)*(-(4/3)*z^3/h^2)/((1-nu(z)^2)) ------> D12

By using above substitutions, exp1 reduces to:

exp1:= A11*(diff(t(r), r))+A12*t(r)/r+(B11+D11)*(diff(y(r), r))+(B12+D12)*y(r)/r+D11*(diff(diff(p(r), r), r))+D12*(diff(p(r), r))/r;

How I can perform some substitutions by using MAPLE commands such as either "algsubs" or any other commands or applying any possible method In MAPLE?

Thanks in advance.