Linear Buckling topology optimization problem
Altair Employeehello,
I need your help to solve a problem on linear buckling topology optimization
I am doing topology optimization for linear buckling case of simply supported I-section beam (slenderness ratio-120) having compressive axial load. Beam is made up of shell elements. I have given base thickness 3mm and my design space thickness 6mm.
I have considered two cases
I-case
Objective- minimization of compliance
Constraints- buckling and volume fraction (0.4)
problem- Infeasible design , I am getting negative buckling eigenvalues and it violates my buckling constraints (lower bound=1). ( direction of my load cannot be reversed). I am applying load which are having magnitude below buckling load factor.
II- case
objective –minmax –objref-(minimizing the maximum buckling eigenvalue)
constraints- volume fraction.
Problem- In second case I am getting positive eigen value but my volume fraction become so less in 4th and 5th iterations (10^-2) .therefore I am not getting any topology
Also I have applied Topology optimization with minimum member size and 2-plane symmetry constraints in both cases.
i am attaching *.out file.
Results are not satisfying , could you please help me out.
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Altair EmployeeDear Rahul,
I have increased the number of iterations to 150, even the same problem gets continued i.e limits on iterations reached. In this case i have changed the basethickness to 1mm. i am attaching the file.
also is there any solution to my II-case problem.
Could you share us .fem file?You can use my dropbox.
Altair EmployeeI have shared .fem files in your dropbox.
Could you enter V1 as 0 in EIGRL card and run simulation.
Altair Employeethanks , it works
Thanks for the update.
for case 1 try below option.
Please increase the number of iterations to 120 (Analysis >> Optimization>>Opti control>>Desmax) and rerun the analysis