

Re: Simulating a ramp?
Mildred Mattice Nov 7, 2013 10:36 AM (in response to Mildred Mattice)Here is an absolute great example of what I want to do:
http://www.youtube.com/watch?v=RT_xT3b58Zc
I just have no idea how to do it...

Re: Simulating a ramp?
Anthony Botting Nov 7, 2013 10:14 PM (in response to Mildred Mattice)HI Mildred: You can do this but the NL solver is very sensitive to finite displacement with no deformation, esp. at the start of the analysis (the nonlinear dynamic solver is not really designed to solve for that case). However you should be able to get around it if you put the block right up against the triangular component. Provide an initial velocity to the rectangular block. This way, the two components startout already incontact.
Since the rectangular block has a sharp corner touching the flat face, the solver might have some difficulty with the contacts. You can try beveling the initial contact edge of the rectangular block such that a larger surface startsoff incontact with the triangular block face.
For quick turnaround trial runs you can also take advantage of symmetry by cutting the components along a centerline vertical plane in the longitudinal direction and applying a sliding bc on the cut faces.

Re: Simulating a ramp?
Mildred Mattice Nov 8, 2013 8:55 AM (in response to Anthony Botting)Thank you for your response.
This is a simplified, example model, to test the feasibility of the simulation, before spending time on modeling the full, complex model in SolidWorks. I suppose even in this simplified model, I could save time by using symmetry .
I will try what you suggested: fillet/round the retangular block corner face, and try running it.


Re: Simulating a ramp?
Jared Conway Nov 8, 2013 1:47 AM (in response to Mildred Mattice)Why not fix the bottom of the triangle just to simplify the restraints?
Did you use initial velocity? I haven't had much luck with that. I'd use another method. Often the parts don't move with initial velocities.
Regarding mass, the software uses density and volume of the part.
You may want to post the model for a bit more help.

Re: Simulating a ramp?
Mildred Mattice Nov 8, 2013 8:59 AM (in response to Jared Conway)Thank you for your response as well.
I do not want to fix the bottom of the triangle, as I want the trianglular base to be able to deform. It is to my knowledge that if I use fixed geometry, the model will not be able to expand or contract in the said axes of that plane.
As for the intiial velocity, I too haven't had much luck with that... it doesn't seem to move!
With the mass, I suppose I have to use m = pV = p*(l*w*d), and just calculate the depth...
And finally, as for the model, this was an over simplification, and not the final, intended, simulation.

Re: Simulating a ramp?
Jared Conway Nov 8, 2013 2:13 PM (in response to Mildred Mattice)I do not want to fix the bottom of the triangle, as I want the trianglular base to be able to deform. It is to my knowledge that if I use fixed geometry, the model will not be able to expand or contract in the said axes of that plane.
>what do you wnat to expand/contract? what do you think your current setup allows? also my recommendation here for fixed is to simplify the problem to get started. you can add more complexity later
As for the intiial velocity, I too haven't had much luck with that... it doesn't seem to move!
>it should but i have seen this problem before dependent on the way you've setup other things. posting the model is the best way to troubleshoot this.
With the mass, I suppose I have to use m = pV = p*(l*w*d), and just calculate the depth...
> i'm not sure what you're looking to do here. mass is taken into account by the software automatically. unless you're trying to get a specific mass by back calculating the density.
And finally, as for the model, this was an over simplification, and not the final, intended, simulation.
> this is the best way to start any new analyses. especially if you're new to the study type. i'd even recommend trying to make this a static analysis to start with an idealized impact. that should help you understand what trends to expect from the dynamic.

Re: Simulating a ramp?
Mildred Mattice Nov 11, 2013 8:30 AM (in response to Jared Conway)Jared Conway wrote:
>what do you wnat to expand/contract? what do you think your current setup allows? also my recommendation here for fixed is to simplify the problem to get started. you can add more complexity later
Because it is fixed in the xy direction, it won't be able to move in said directions. However, it can move in the zdirection. This is what I expect the "roller/slider" and the "0mm translation" options to do.
Jared Conway wrote:
> i'm not sure what you're looking to do here. mass is taken into account by the software automatically. unless you're trying to get a specific mass by back calculating the density.
The final model (not this over simplification) must be able to withstand a 5kg round object hitting it at 10 m/s. So I was wondering if I can just create a spherical ball (of any size) and give it a mass of 5kg, instead of choosing a material, and making a specificsized spherical ball.
Jared Conway wrote:
> this is the best way to start any new analyses. especially if you're new to the study type. i'd even recommend trying to make this a static analysis to start with an idealized impact. that should help you understand what trends to expect from the dynamic.
Yup. I've never done dynamic analysis in SolidWorks, so trying this out. Problem with static is that I do not know what type of force will be exerted by the round object.
For example, how would you translate the kinetic energy of that 5kg object (traveling at 10 m/s) into a static force? I guess you can make the kinetic energy = work required to stop the car such that:
0.5*m*v^2 = Favg*d
Favg = (0.5*m*v^2)/d
So if I set the distance required to stop the ball at 10cm, that would give me:
Favg = (0.5*5kg*(10m/s)^2)/0.1m = 2500N
That, however, is the average force, and is also of it stopping at 10cm. I have no idea if this assumption of stopping at 10cm is valid or not, because the design will have a curved wall.

Re: Simulating a ramp?
Jared Conway Nov 11, 2013 11:03 PM (in response to Mildred Mattice)seems all reasonable except that the mass of a part is based on volume x density always except for a remote mass.
if you're still stuck, i'd upload your model.




