I am using ANSYS APDL. I using contact algorithm in my analysis which enforces non-linear solver. I am giving load which is linearly increasing. I am giving this linear load into 20 load-step. but it consumes lot of time. so I want to know the effect of no. of load-steps and substeps. what I should do to reduce computational time. I can reduce load-steps and increase sub-steps or vice-versa. please suggest the better one.
Well……If you will apply load in 20 load steps (let say one substep per step) you are forcing ANSYS to solve the equation F=kx at least 20 times also as it is a nonlinear problem, every time stiffness matrix will be updated…….updating of stiffness matrix can be avoided (nropt command) but it is not recommend as you are solving a nonlinear problem with contact and the results will be compromised……In my opinion step or substep doesn’t matter……
As per my understanding time can be reduced only by reducing the number of.... how many time ANSYS solves the equation and how many times it updates the stiffness matrix…..You can try one thing...apply full load in single step…..give very high flexibility in nsub command (like nsub,20,200,10) and put autots,on and allow ANSYS to calculate the shortest possible time to solve the problem….
Hope that will help….
Naveen
I am using Comsol and my problem also involves contact analysis. Reducing the time step taken by the solver increases the solver accuracy and may also solve the contact analysis convergence issue you are facing although it will increase computational time.
Kindly let me know if you get some feasible solution to your problem
Well……If you will apply load in 20 load steps (let say one substep per step) you are forcing ANSYS to solve the equation F=kx at least 20 times also as it is a nonlinear problem, every time stiffness matrix will be updated…….updating of stiffness matrix can be avoided (nropt command) but it is not recommend as you are solving a nonlinear problem with contact and the results will be compromised……In my opinion step or substep doesn’t matter……
As per my understanding time can be reduced only by reducing the number of.... how many time ANSYS solves the equation and how many times it updates the stiffness matrix…..You can try one thing...apply full load in single step…..give very high flexibility in nsub command (like nsub,20,200,10) and put autots,on and allow ANSYS to calculate the shortest possible time to solve the problem….
Hope that will help….
Naveen
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