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# Optimize spring damper stiffness and damping coefficient

## Optimize spring damper stiffness and damping coefficient

(OP)
Hello, I am trying to simulate an impact between a spring damper attached to a body and the ground. I have attached an image to better understand

.

As you can see, a spring damper is attached with 2 bodies, one with a bigger mass and one with null mass (used only for contact purpose). As you can see I have plotted the deformation of the spring on impact. What I want to do is to run an optimization for the stiffness and damping coefficients to find the best values so that the max deformation doesn't exceed 10 mm. My problem is I don't know exactly how to build the objective function because the deformation is variable and I only want to consider the maximum deformation. Does anyone know any solution for this problem ?

### RE: Optimize spring damper stiffness and damping coefficient

Have you done the tutorial on running a DOE from View, Using Adams/Insight with Adams/View? Basically you need to create a response that latches at the maximum (abs(displacement)) seen so far, but I don't use View and I haven't done it myself. I'll be interested to see the correct solution.

Cheers

Greg Locock

New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?

### RE: Optimize spring damper stiffness and damping coefficient

Why not try to Create a "Function Measure", where through "Function Builder" enter an expression of the type "abs (SPRING_1_MEA) -10", and then in the optimization window Design Evaluation Tools specify the goal to "minimize". The variables will be the values "DV_stif" and "DV_damp", for which min and max will be from 0 to 10000, for example. Write them in the coefficients of the spring. In theory, at the end you will be given a value at which the spring is compressed exactly 10mm. Do not exceed it.

Sorry for my English)

### RE: Optimize spring damper stiffness and damping coefficient

Because the function builder expression will result ina time history. It is not max(abs (SPRING_1_MEA) -10), it is a curve of abs (SPRING_1_MEA) -10 vs time.

Cheers

Greg Locock

New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?

### RE: Optimize spring damper stiffness and damping coefficient

(OP)
I have tried what you have mentioned @newbie_user. My only problem is that the optimization [abs (SPRING_1_MEA) -10] is not reaching 0 when minimizing the results, sometimes it reaches negative values. Overall the values are close to 0, something like 2.35 or -1.5, but I want to find the values for stiffness and damping that will give me a precise 10mm compression. I have noticed that the values are also influenced by the precision that you set on the optimizer. I think I am going to play a bit with those values to see if I can get a better result.

Thanks,
Cosmin

### RE: Optimize spring damper stiffness and damping coefficient

newbie_user, ah, I'm not a habitual View user, I'd assumed that optimisation was being done inside Insight, I hadn't realised that it was integrated into View. neat.

Cheers

Greg Locock

New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?

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