Geometry settings question

Hi,

you can use scale option to scale the component with some units and then use a solid edit option or while importing you have the option to provide scale factor.

let say while modelling in Cad you would have kept the units in meter.so if you want your model to be in mm, then give scale factor of 1000,for inches give scale factor of 25.4 that will bring model in mm.

By the way what component you have with such small dimension?please crosscheck the thichkness with distance panel.

Regards

Rahul R

What settings in HyperMesh v12.0 control your ability to make a very tiny geometry cut? I am trying to section off a part of a component to the size of 0.25 microns and am having issues in the program with it allowing me to make a solid edit that small. 

 

Thank you

Hi

Try reducing Geometry Tolerance (Preference > Geometry Options)

But you should not make tiny objects in HM, instead of that, make them normally and assign an appropriate unit

for example you choose unit is 'mm' and create 0.25-micron objects, you have to input 0.00000025

but you can input 0.25 and choose unit is 'micron'

too small number will have low precision and generate incorrect results

Thanks for the replies. I will attempt these today and report back with the results. To answer your question Rahul I am modeling a crack in a bolt for J-Q fracture analysis and am using the 0.25 microns as the dimensions for the crack thickness. 

@cer54: with a crack size about 0.25 micron, I think you have to choice the geometrical tolerance about 1/20~1/50 of 0.25 micron.

If your tolerance is too 'big' comparing to your crack size 0.25 micron, you can not do geometrical operations.

The same principle shoud be applied to the mesh too.

Update: I have tried using the scaling option but when I do my some of the circles that make up my contour region vanish. This is the same whether I scale in the 3D software then import and when I import the original file and scale using hypermesh. (I have attached screenshots of this issue)

@Q.NGUYEN-DAI I have actually set the geometry tolerance as small as 1x10^-11 and I still get the same results. The program simply will not cut the geometry. Currently my lines are drawn on a center plane and I am using 'solid edit - with sweep lines'. My next step is to attempt drawing the partition geometry outside of the solid and using a vector to define the cut.

I will post again tomorrow or tonight with an update on the issue.

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

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

Update: I have tried using the scaling option but when I do my some of the circles that make up my contour region vanish. This is the same whether I scale in the 3D software then import and when I import the original file and scale using hypermesh. (I have attached screenshots of this issue)

 

@Q.NGUYEN-DAI I have actually set the geometry tolerance as small as 1x10^-11 and I still get the same results. The program simply will not cut the geometry. Currently my lines are drawn on a center plane and I am using 'solid edit - with sweep lines'. My next step is to attempt drawing the partition geometry outside of the solid and using a vector to define the cut.

 

I will post again tomorrow or tonight with an update on the issue.

If I scale these lines back down to 1:1 the circles return. Not sure if this clarifies the issue

I tried making a cut with the lines that did appear on the scaled model. Still not working. At this point my cleanup tol is set to 1e-06, which in this scaled model is 0.000001 microns and the software still will not make the 0.25 micron notch.

I am beginning to fear that a bug in the software might be keeping me from progressing on this model. The time I am spending on modeling this geometry is consuming my time that I have for analysis and thesis writing.

I tried making a cut with the lines that did appear on the scaled model. Still not working. At this point my cleanup tol is set to 1e-06, which in this scaled model is 0.000001 microns and the software still will not make the 0.25 micron notch.

 

I am beginning to fear that a bug in the software might be keeping me from progressing on this model. The time I am spending on modeling this geometry is consuming my time that I have for analysis and thesis writing.

Why don't you use unit as 'nm', your input number will be 250nm

it is so easy with hypermesh

Why don't you use unit as 'nm', your input number will be 250nm

it is so easy with hypermesh

The 3D modeling software I have access to at the university does not support nanometers unfortunately. 

Could you share your model ?

If 'yes', show us exactly what you are trying to do please.

When I try to upload the .stp and .hm files it states that I am not permitted to upload them. For this reason I have uploaded them to google drive and provided the links.

https://drive.google.com/file/d/0BwTnnF_ep_EbRkVxT2tuM1BmQTA/view?usp=sharing

https://drive.google.com/file/d/0BwTnnF_ep_EbTWFuaDNjTGJBWkU/view?usp=sharing

image1 shows the geometry that I am working with. This is how the specimen will be prepared for laboratory testing. 

image2 shows the contours that need to be cut out of the component along the y-axis to provide a straight cut. 

image3 shows the 0.25 radius crack that needs to be removed from the model.

The main concern is the smallest contours and the crack thickness as they are giving the biggest problem. 

Thank you again for your help, it truly is greatly appreciated.

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

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

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

I am going to attempt deleting my sketches in the 3D software, scaling the model to 1000x, then redoing the sketches

I am going to attempt deleting my sketches in the 3D software, scaling the model to 1000x, then redoing the sketches

This method was also a flop. It actually gave worse results than the previous methods as far as not bringing in the sketched circles is concerned.

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

I have almost fixed this issue. What I did was actually section the components off in the 3D modeling software and made an assembly with the pieces. I am now facing an issue however where hypermesh does not seem to realize that I wish for these components to be meshed together, and not have meshes independent of each other. 

The image below shows an example of the software not using the existing neighboring mesh. This image is exaggerated and doesn't match the actual mesh dimensions I am looking for, but I wanted to show the high contrast between the regions.

This seems to me like it would be an easy fix, but I am not familiar enough with the program yet to know the method.

Thank you

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

For which solver you work?

In order to avoid too much different of meshing size, you can make some 'transitory' zones.

For example from size of 1mm to size of 10mm: 1mm => 3mm => 6mm => 10mm

For which solver you work?

In order to avoid too much different of meshing size, you can make some 'transitory' zones.

For example from size of 1mm to size of 10mm: 1mm => 3mm => 6mm => 10mm

I am working in Abaqus. I wish for these meshes to be the same size, but I want them to be connected as the are actually imported as two separate solids. Each contour has 24 nodes around the outer and inner diameter and is only 1 element thick. 

I need to know if there is a way for Hypermesh to base the mesh of the unmeshed solids off of and connect to the meshed regions I have already created.

Thank you

If I understand your question correctly, you will have to use mesh > imprint , read about this feature in help. 

If I understand your question correctly, you will have to use mesh > imprint , read about this feature in help. 

I believe this is exactly what I am looking for! I will need to play around with the feature to make sure I learn it correctly, but I it appears it will do the trick. Thank you!