# Can I define a deflection limit for topology optimization

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We want to do topology optimization on the hinge component (red) and the rest parts remain the same. The upper and lower surface of the pin (blue) is constrained (6DOF) and there is a 20N upward force on the edge of the door (yellow)

We want the vertical deflection of the loading point on the door be less than 7 mm

For now, we set the design constraint as the volume fraction value of the hinge, say 0.4 as the upper bound, and the objective is to minimize the compliance of the hinge.

There are two questions:

1. After the topo opt, the linking area between the hinge and the door is really weak, as Figure 2 shown. Is it because that we only considered the compliance of the hinge and hypwework will not consider the linking problem between components? If we modify the design area a little bit (leave the linking area as undesigned space), can we solve this problem? Or there is other ways to deal with it?

2. After we got the topo result, we ran a FEA test and it showed that the deflection of the loading point exceeds the limit. Can we define a deflection limit as the design constraint before we run the topo opt? If so, how can we do that? If not, what can we do to minimize the deflection? (maybe we set a wrong objective?)

Thank you!

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Try minimizing mass/volume with a constraint on displacement.

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2 hours ago, Prakash Pagadala said:

Try minimizing mass/volume with a constraint on displacement.

How to define a displacement constraint? Especially that the displacement is not on the design area but on the loading point outside of the design space.

Do we have any tutorial for the displacement constraint definition?

Thank you!

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Hi,

Yes you can define a displacement constraint which is not in design space.

If you have help installed, please refer to the attached tutorial tile.

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