Shear failure in bolt

harshitpuri

i am trying to simulate shear failure in bolt in which head of bolt tears off due to shear load. I've used type 13 spring along with a local co-ordinate system and pre-tension curve . What is the best way to capture shear load failure. and what is the best way to apply pretension type 32 or type 13 spring. Should washers be modeled as rigid.?

Pranav Hari

Hi harshitpuri

 

As per Radioss theory manual the best way to capture shear load for a bolt is by using  two rigid bodies (/RBODY) connected to each set of parts which are linked with the bolt and then set one type 13 spring element (/PROP/SPR_BEAM) between both rigid bodies. With this method it is possible to describe the elasto-plastic behavior rupture behavior in any direction, and the force passing through the bolt (normal force, shear force, moments) could be output, using /TH/SPRING. However there are many methods to model failures in bolt. 

Please see Radioss theory manual for various bolt modelling options and you can  choose according to your requirement.

 

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Altair Forum User said:

nd what is the best way to apply pretension type 32 or type 13 spring

 

May be this Radioss tutorial from help may also help you. In this tutorial the bolt pretensioner is given using Type 32 property

 

<?xml version="1.0" encoding="UTF-8"?>

 

 

Thanks

Andy_20955

Hi,

Note that /PROP/SPR_PRE (TYPE32) only includes stiffness in the axial direction.  If you use TYPE32 you will need to include a second TYPE13 with stiffness in DOF 2-6 to model the other bolt stiffness. 

Note that RD-T: 3510 tutorial doesn't include the TYPE13 spring. 

To model the shear failure, you can define failure values in the TYPE13 spring.

Please read the comments in the TYPE32 spring about the pretension force curve needed to go to zero to lock the pretension force.  If you don't lock the spring then the pretension force is always applied in the model.

 

Thanks,

Andy

Andy_20955

Hi,

I have attached an example model of using two spring in series to model the failure and pretension.  For pretension one type 32 spring with a second duplicated element with type13 spring for DOF 2-6.  A second TYPE13 spring includes the failure properties. 

As far as modeling the washer as rigid or not it depends on how detailed of a model you want to create.

Thanks,

Andy

Unable to find an attachment - read this blog

harshitpuri

Thanks Andy.

But i am using Hypermesh 13 and file you have sent belongs to HW 18.

Can you convert this into block 120?

Simon Križnik

Hi @harshitpuri

 

the model was converted to block 120 as requested:

Unable to find an attachment - read this blog