Regarding Composite optimization in optistruct

Faisal

Hello everyone,

As i am working on a composite optimization in optistruct, I have a model on which i have two load cases at the moment, I will try to state the problem in briefly,

1.My aim is to get the displacement at a range between 15 to 18mm in one load case and in the second load case which is Non-linear it should be below 40mm.

2. I have to consider the composite failure as well in my model which is PUCK failure.

3. I am working with the free size, size and shuffle optimization before doing the optimization i run the basis analysis of my model and i am getting the displacement for the first load case is around 14mm and for the second one is 38mm.

4. I have tried with so many possibilities during the optimization but didnt get the solution. I kept response as compliance, static displacement, and composite failure. I am bit confused whether this responses are correct for my case or not.

5. Constraints i give for displacement. Objective is to minimiese compliance.

I look forward for your reply it would be very helpful if someone give your advice on this concern.

yuhaohe

Hi,

 

By "didn't get the solution", do you mean the optimization cannot find a feasible design?

Here is my suggestion:

1. Please check the .out file and see what constraint is violated.

2. Before you do free size optimization, you just need to create one ply with each orientation with maximum possible thickness. I remember free size will only reduce the thickness but will not increase over the initial ply thickness.

3. Free size is more like concept design, it is better not to put all constraints into the problem at this stage. You may minimize mass while constrain the displacement. You may add a few manufacturing constraints such as balance and max thickness percentage of each angle.

4. You may need to run multiple free size optimization with slightly different setup to give you better insight. The purpose of free size optimization is not to provide a feasible design directly, but to give engineers some insight of the problem's nature. 

5. Based on the results from multiple free size runs, create the ply shapes of each ply. Make sure the ply shape is reasonable and manufacturable. Assign a proper thickness upper and lower bound for each ply.

6. When you run sizing optimization after step 5, you may include more constraints such as composite failure.