Can mechanism (MDO) do this?

[Jon_Bradley]

Hi I want torun a dynamic analysis ofa box shaped part landing onto a surface,analogous toa deck of cards being thrown onto a table.


I've had a play and cannot think how to define the constraints, etc to achieve this.


The box must not penetrate the surface of the flat plate when it comes into contact. A cam connection is not possible because there mustbe a6DOF constraint on the box (cams only work in a 2D plane)


Is there a method of preventing two bodies from interfering with each other?


Thanks in advance,


Jon.

 

[deepakbhat_nie]

Are you trying to do something like crash analysis. if yes then mechanica cannot handle it. use lsdyna insted.


Regards,


Deepak Bhat

 

[Jon_Bradley]

I was thinking of using the "mechanism" application, not"mechanica" (I have never used mechanica so I'm unsure of its capabilities). Also I have never heard of "lsdyna" that you mentioned...


What I want to ultimately achieve is this:


A 3D dynamic vehicle model on a road surface, to which forces can be applied at its CoG that represent the centrifugal forces it experiences when going around a corner. The suspension should move as a result and ultimately I want to use measures to find out the traction forces at the tyres.


Is this possible in any of the 3 softwares mentioned?


Thanks,


Jon
Edited by: Jon_Bradley

 

[Israr]

the solution is MDO with customized loads, INTEC SIMPACK, MSC ADAMS, or LMS DADS.


Israr

 

[Jon_Bradley]

Thank you. However I have used MDO with customised loads, but the problem is this:


The wheels must have 6DOF to account for the car rolling/yawing/pitching (3DOF) but alo because as the car rolls,etc, the wheelbase/track widthnaturally gets slightly shorter due to pythagoras (2DOF). The 6th DOF is because it would be nice to see when wheels lift off the ground.


This is where my problem is - with 6DOF the car will just disappear when I apply loads. SO I thought if I could make it rest on a flat plate with friction, this would be prevented. However I can't work out how to do this..


Any suggestions?


TIA, Jon
Edited by: Jon_Bradley

 

[Israr]

I have solved a problem identical to yours, but how to send it to you? The size is more than 50 Mb.


Israr

 

[Israr]

Jon_Bradley,


By the way your profile is incompete. I would like to kow who are you.


Israr

 

[Jon_Bradley]

Israr, I've updated my profile - I am student of Mechanical Engineering at Nottingham University, UK. I am trying to create a dynamicmodel our university's Formula Student race car for my dissertation work.


Since my last post I have madesome progress: using ball joints atthe centre of each tyre contact point and also adding lateral tyre stiffness allows enough motion to achieve 90% of my aims. However I'm still stuck because Pro/E only lets you measure the total radial connection force of a ball joint... Ineed to knowits individual x, y and z components, but I can't see how to do this.


I would love to see your solution, Israr... I think my university inbox accepts 50MB (I need to confirm this). Do you have an email client that will allow you to send this file size? And are you willing to send it to me?


I am very grateful for your help.


Jon Bradley.