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Transcript
00:02
Contact sets.
00:05
In this video we'll use automatic contacts, create a manual contact set and we will manage contact sets.
00:12
In Fusion 360 let's carry on with our motorcycle rear set model prep.
00:17
At this point, we have three separate simulation models.
00:21
We have our bracket frame mount, bolted bracket and frame mount as well as the last one we created, which is frame mount only.
00:28
In the frame mount only, there's a single part to analyze so we don't have to worry about contact sets.
00:34
If we activate our bolted bracket, we added our bolted connections.
00:38
This automatically dictates exactly how those two pieces are held together.
00:43
There are some inherent things that we need to understand about the differences between bolted connections,
00:48
and the way that Fusion 360 handles contact sets.
00:52
If we hide our bolted connections and we take a look at the interface.
00:57
This design was originally using a flathead.
01:00
This flathead essentially pushes on the tapered face and if it's threaded or bolted on the other side, it's then holding those two pieces together.
01:10
The bracket itself is not bonded or welded to the frame mount, but it is held in place by this tapered face,
01:18
meaning that there's very little deformation that happens assuming that we're inside of the material properties of the hardware.
01:25
If we go to our bracket and frame mount, this design has a degree of freedom left because we haven't done anything to the bracket itself,
01:34
it's still free to move and we can't solve this study because this bracket would simply just move in space,
01:40
and it wouldn't fall into the correct category for a linear static stress,
01:44
which is looking at very small deformations within the linear range of the material.
01:49
So we need to tell Fusion exactly what has to happen between the frame mount and the bracket.
01:54
To do this, we go to our contacts and we can either create automatic contacts or manual contacts.
02:01
Automatic contacts are pretty good for 95% of cases.
02:06
We simply need to have a contact detection tolerance.
02:09
In this case, the two parts are touching each other so 0.1 mm is going to be fine and we select generate.
02:16
A progress dialog will appear as the contacts are being generated and then everything goes away and Fusion is happy.
02:24
However, that's not the end of the story.
02:26
We need to make sure we understand what happened.
02:29
So we'll go to manage contacts and we'll see what happened.
02:33
We have three contacts that were created.
02:36
All three are bonded and the penetration type is symmetric.
02:40
This fillet on the left hand side is bonded to the face of our bracket.
02:45
The back face of our pivot bracket is bonded to the face of our frame mount and then on the right hand side the fillet is also bonded.
02:54
So again, this is not necessarily realistic for the way these two components are held together.
03:01
If they were welded, then a bonded contact set would likely be a good option.
03:06
If they are welded just along these vertical edges, then we would want to suppress the bonded contact set for the middle.
03:13
However, for this example for bonded one and bonded three, we're going to right click and we're going to suppress those contacts sets.
03:21
The next thing that we need to identify is whether a bonded contact set really makes sense for the way these two pieces are held together.
03:29
In some cases simply using our simplify tools to split faces on the bodies and create that bonded connection is good enough.
03:38
However, in our case this is not a realistic option.
03:43
So the entire back face being bonded together,
03:46
if we were looking to identify how the forces are transmitted between the two, this might get us close enough.
03:54
So we can leave bonded or we can take a look at some of the other types.
03:59
For this example however, I'm going to right click and I'm going to suppress that bonded contact set,
04:04
which takes us exactly back to where we started with this thing being completely free.
04:09
The reason that I want to do this is because I want to explore manual contacts.
04:14
In order to create a manual contact, we need to select the primary body and then a secondary body.
04:20
I'm looking at the connection between these two brackets and I need to determine how they're held together.
04:26
For selection set 1 I'm going to use the face of the frame mount.
04:30
For selection set 2, I need to use the back side face of the pivot mount.
04:34
If I rotate this around, I'm able to select through the solid body.
04:38
Notice that it gives me a warning because there's already a reference contact set even though we suppressed it.
04:44
I'm going to say Ok and note that it's not going to allow me to bond those together.
04:50
The only way that I can get around this is by bonding an edge to the face.
04:55
So if I select the edge instead of the entire back face, then it will allow me to create this.
05:02
When I make this option, you'll notice that I can change the contact type on the fly here,
05:07
from bonded to separation to sliding too rough or offset bonded.
05:12
Bonded and offset bonded will essentially provide the same results,
05:16
however offset bonded assumes there's some sort of gap that's outside of the range of that tolerance value.
05:22
When we have the other options such as separation,
05:26
it will allow the two bodies to separate or pull apart from each other but not allow them to penetrate each other or go through.
05:34
The sliding will allow them to slide but not separate and rough will allow them to separate without penetration but it will not allow it to slide.
05:44
In our case once again, I'm not going to be using this manual contact but it's important that we understand some of our options.
05:51
We have something that's called our automatic max activation distance,
05:56
where if we toggle that on, you'll notice that it takes away our activation distance option.
06:02
It also allows us to expand our advanced options and we can modify things like the stiffness factor,
06:09
or if there's any penetration offset and an important aspect is to note that we also have a frictional stiffness for stick.
06:17
So some of these values are extremely important depending on how your components interact with each other.
06:23
Let's cancel this.
06:25
Let's go back to our manage contacts.
06:28
Let's go back to bonded to an unsuppressed,
06:31
and note that the pencil icon next to it allows us to go into that contact set and gives us the same options as creating a manual contact.
06:40
For our example since the main focus is going to be the frame mount itself without the pivot bracket, I'm going to leave the bonded contact,
06:49
because this allows us to have the entire design potentially fixed,
06:53
and now we have our bracket and frame mount ready to solve, we can see here the pre check is now green.
06:59
If we go to our bolted bracket, it's now ready to solve and if we go to our frame mount only, it's ready to solve as well.
07:07
With those three studies ready to solve, let's make sure that we do save before moving on.
Video transcript
00:02
Contact sets.
00:05
In this video we'll use automatic contacts, create a manual contact set and we will manage contact sets.
00:12
In Fusion 360 let's carry on with our motorcycle rear set model prep.
00:17
At this point, we have three separate simulation models.
00:21
We have our bracket frame mount, bolted bracket and frame mount as well as the last one we created, which is frame mount only.
00:28
In the frame mount only, there's a single part to analyze so we don't have to worry about contact sets.
00:34
If we activate our bolted bracket, we added our bolted connections.
00:38
This automatically dictates exactly how those two pieces are held together.
00:43
There are some inherent things that we need to understand about the differences between bolted connections,
00:48
and the way that Fusion 360 handles contact sets.
00:52
If we hide our bolted connections and we take a look at the interface.
00:57
This design was originally using a flathead.
01:00
This flathead essentially pushes on the tapered face and if it's threaded or bolted on the other side, it's then holding those two pieces together.
01:10
The bracket itself is not bonded or welded to the frame mount, but it is held in place by this tapered face,
01:18
meaning that there's very little deformation that happens assuming that we're inside of the material properties of the hardware.
01:25
If we go to our bracket and frame mount, this design has a degree of freedom left because we haven't done anything to the bracket itself,
01:34
it's still free to move and we can't solve this study because this bracket would simply just move in space,
01:40
and it wouldn't fall into the correct category for a linear static stress,
01:44
which is looking at very small deformations within the linear range of the material.
01:49
So we need to tell Fusion exactly what has to happen between the frame mount and the bracket.
01:54
To do this, we go to our contacts and we can either create automatic contacts or manual contacts.
02:01
Automatic contacts are pretty good for 95% of cases.
02:06
We simply need to have a contact detection tolerance.
02:09
In this case, the two parts are touching each other so 0.1 mm is going to be fine and we select generate.
02:16
A progress dialog will appear as the contacts are being generated and then everything goes away and Fusion is happy.
02:24
However, that's not the end of the story.
02:26
We need to make sure we understand what happened.
02:29
So we'll go to manage contacts and we'll see what happened.
02:33
We have three contacts that were created.
02:36
All three are bonded and the penetration type is symmetric.
02:40
This fillet on the left hand side is bonded to the face of our bracket.
02:45
The back face of our pivot bracket is bonded to the face of our frame mount and then on the right hand side the fillet is also bonded.
02:54
So again, this is not necessarily realistic for the way these two components are held together.
03:01
If they were welded, then a bonded contact set would likely be a good option.
03:06
If they are welded just along these vertical edges, then we would want to suppress the bonded contact set for the middle.
03:13
However, for this example for bonded one and bonded three, we're going to right click and we're going to suppress those contacts sets.
03:21
The next thing that we need to identify is whether a bonded contact set really makes sense for the way these two pieces are held together.
03:29
In some cases simply using our simplify tools to split faces on the bodies and create that bonded connection is good enough.
03:38
However, in our case this is not a realistic option.
03:43
So the entire back face being bonded together,
03:46
if we were looking to identify how the forces are transmitted between the two, this might get us close enough.
03:54
So we can leave bonded or we can take a look at some of the other types.
03:59
For this example however, I'm going to right click and I'm going to suppress that bonded contact set,
04:04
which takes us exactly back to where we started with this thing being completely free.
04:09
The reason that I want to do this is because I want to explore manual contacts.
04:14
In order to create a manual contact, we need to select the primary body and then a secondary body.
04:20
I'm looking at the connection between these two brackets and I need to determine how they're held together.
04:26
For selection set 1 I'm going to use the face of the frame mount.
04:30
For selection set 2, I need to use the back side face of the pivot mount.
04:34
If I rotate this around, I'm able to select through the solid body.
04:38
Notice that it gives me a warning because there's already a reference contact set even though we suppressed it.
04:44
I'm going to say Ok and note that it's not going to allow me to bond those together.
04:50
The only way that I can get around this is by bonding an edge to the face.
04:55
So if I select the edge instead of the entire back face, then it will allow me to create this.
05:02
When I make this option, you'll notice that I can change the contact type on the fly here,
05:07
from bonded to separation to sliding too rough or offset bonded.
05:12
Bonded and offset bonded will essentially provide the same results,
05:16
however offset bonded assumes there's some sort of gap that's outside of the range of that tolerance value.
05:22
When we have the other options such as separation,
05:26
it will allow the two bodies to separate or pull apart from each other but not allow them to penetrate each other or go through.
05:34
The sliding will allow them to slide but not separate and rough will allow them to separate without penetration but it will not allow it to slide.
05:44
In our case once again, I'm not going to be using this manual contact but it's important that we understand some of our options.
05:51
We have something that's called our automatic max activation distance,
05:56
where if we toggle that on, you'll notice that it takes away our activation distance option.
06:02
It also allows us to expand our advanced options and we can modify things like the stiffness factor,
06:09
or if there's any penetration offset and an important aspect is to note that we also have a frictional stiffness for stick.
06:17
So some of these values are extremely important depending on how your components interact with each other.
06:23
Let's cancel this.
06:25
Let's go back to our manage contacts.
06:28
Let's go back to bonded to an unsuppressed,
06:31
and note that the pencil icon next to it allows us to go into that contact set and gives us the same options as creating a manual contact.
06:40
For our example since the main focus is going to be the frame mount itself without the pivot bracket, I'm going to leave the bonded contact,
06:49
because this allows us to have the entire design potentially fixed,
06:53
and now we have our bracket and frame mount ready to solve, we can see here the pre check is now green.
06:59
If we go to our bolted bracket, it's now ready to solve and if we go to our frame mount only, it's ready to solve as well.
07:07
With those three studies ready to solve, let's make sure that we do save before moving on.
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