Best way to simulate a flexible belt and allow rigid contacts

Shaun Smith
Shaun Smith New Altair Community Member
edited August 2021 in Community Q&A

Hey Everyone,

 

I'm try to simulate a conveying rig in MotionView and need the belt to be flexible and allow contacts to rigid bodies at areas that aren't joints. I've looked into using flex bodies and NLFE's and from what I can gather the only way contacts can be specified between flexible and rigid bodies is by attaching many small rigid bodies to the flexible body with fixed joints, then specifying contacts between those bodies and the other bodies in my model.

 

I'm also planning on using the coupled MBD-DEM feature later on and also need to know if a flex body can interact with the particles that I generate or whether the same rigid to flexible contact problem will be an issue.

 

Is there another less complicated method for solving this problem that you would suggest??

 

Many thanks!

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Answers

  • Praful
    Praful
    Altair Employee
    edited May 2021

    Hello Shaun

    If the belt is flat, MotionView has a Belt-Pulley utility that can be used to build the belt pulley system fairly quickly. For the usage that you described, I would recommend that you use the Discritized Rigid Bodies method.

    image

    Here, the belt element is not truly flexible but it comprises of a series of rigid bodies connected through bushings that represents its flexibility. Please see if this works for you.

    If you still insist to represent the belt as flexible body, then yes what you suggest can be done where certain rigid body can be attached for contacts.

    You could also explore using Point to Deformable surface contact.

    In any case, MotionView + EDEM 2021 onwards support particle interaction with rigid bodies or flexible bodies.

     

    If you can share some more details (picture/model etc..) of the mechanism, we might be able to provide the best possible method.

     

    Regards

    Praful

     

  • Shaun Smith
    Shaun Smith New Altair Community Member
    edited August 2021

    Hi Praful

     

    Thanks for replying! Unfortunately in my design the belt is troughed and needs to flex in the transverse direction as well. I actually have two main designs that I am currently working on simulating for my project. To give some context, both designs are intended to simulate conveying but utilising a stationary belt and having idlers move under the bottom surface of the belt. In one design the idlers oscillate vertically and interact with the same position on the belt while in the other design the idlers move along the length of the belt. I believe the solution I proposed would work for the first design since the contact is only occurring at one position on the belt, but the Point to Deformable Surface option seems like it would be the only option for the second design.

    Since I'm still very new to MotionView I'm still trying to learn how to use PTdSF contacts.

     

    In addition to my issue with contact along the flex body I am now also experiencing some issues in creating the contacts at the RBE2 points. Since the belt geometry is flat, I cannot specify constraints that rely on the belt bending into the troughed position, which is what is required at the ends of the belts. I have attached some images for reference for the belt I am using and the tensors that it needs to be attached at either end.

     

    How can I get around this issue of creating the constraints at the ends of my belt?

     

    Thanks again,

    Shaun

     

    imageimage

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