Appropriate load type for lug analysis

General Questions
1

Hi all! First of all giving a credit for ppm devs, the design and workflow is flawless, Im having a really good time using it, so big thank you.

So my question what would be the appropriate load type for lug analysis? I tried to apply surface traction to the inner surface of the lug hole but it doesnt seem trust worthy cuz it seems to spread load evenly between all the nodes of the surface. I also tried applying concentrated force to the desired place of contact and divided the load by the number of nodes involed, the results seem to be not realistic too.

2

There are no special load types like bearing load in PrePoMax so you would have to use uniform pressure/surface traction applied to partitioned surface or model contact with a rigid pin.

3

Got it, thank you. How do i make a rigid pin? Theres a rigid body constraint, but it asks me for some reference point.

4

Yes, you have to define a reference point. All boundary conditions and loads applied to the rigid part should be applied directly to this reference point.

5

Contact with a rigid pin worked out well, result corresponds with Bruhn’s analytical method. Thank you :slight_smile:

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6

Are you talking about “Analysis and Design of Flight Vehicle Structures” by Bruhn ?

7

Exactly) Afaik the method is developed by both Niu and Bruhn. Niu refers to it in his “airframe stress analysis and sizing” too

8

A bit off-topic but have you seen the new book “Becoming an Aircraft Stress Engineer” by S. Couture ? It seems to be a game changer when it comes to guides for aerospace engineers.

9

Looked it up just now. Damn, looks neat. Definitely going to get one, ty

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