Structural loads

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Structural loads.

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In this video, we will review structural loads, we will create a force, a hydrostatic pressure and a remote force.

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In Fusion 360, we want to carry on with our motorcycle rear set model prep but we also want to open up a supply dataset called simple tank.

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We're going to be taking a look at creating forces, remote forces and hydrostatic pressure.

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Let's start with the simple tank and let's move into our simulation study.

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This is a brand new design so we need to start a new static stress study but no model prep needs to be done.

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We're going to create a constraint and we're simply going to fix the bottom of the tank and then we want to talk about loads applied.

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When we go into our loads there are many different types of loads that can be used.

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First is structural loads which has many different types of loads such as our hydrostatic pressure or pressure.

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We also have linear and angular global loads.

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We have gravity that can be turned on and modified and then we also have point masses.

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For this example, let's move into structural loads and apply a force.

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The force is going to be applied to the top rim of the design.

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I'm going to change the units, set this to pound force, and we're going to assume that we have a 10 pound cap on the top of this tank.

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Now that we have our first force applied you can see that there is a blue glaive that appears on the screen showing the direction of the force.

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As soon as we hover over, it shows that the force is applied to the entire face.

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Next let's go into our loads back in the structural loads and change the type.

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You'll notice that we have pressure which will be evenly distributed across a face.

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We have moments bearing loads, a remote force and then we have our hydrostatic pressure.

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It's important to note there are differences between all of these different types of structural loads.

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For example, if we were to apply a force to the outside face,

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we can limit the target which allows us to determine the size of the area that that force is going to be applied.

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If we were to use a pressure, the pressure is going to be applied evenly across the entire face.

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If we use a moment, we're adding this rotational torque to the face that we've selected.

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If we have a bearing load, the bearing load is going to have a parabolic distribution,

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that would represent a cylindrical body or shaft pushing on another cylindrical body.

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For our example, however, we are going to be focusing specifically on hydrostatic pressure,

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and as soon as we select that as our option, it tells us that gravity is required.

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We're going to say Ok to turn gravity on, we're going to deselect our targets.

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Notice that there is a plane in this design, we want to apply a force on the inside,

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but we don't actually have a split where the fluid is going to be inside of this tank.

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For right now let's go ahead and set this up and we'll make that modification after the fact and fix our selections.

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Notice that it has a select surface point option.

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When we select a surface point, notice that we can select a specific vertex.

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It's not required in our case.

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So we're not going to be using that option.

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The fluid type in our case is going to be water.

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But notice that there are a couple other default options as well as a custom.

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Then you'll notice that the water also brings in its density,

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and the direction of gravity can be shown by expanding our constraints and expanding our loads,

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and then toggling that gravity on we can see on the screen where it's applied.

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Because gravity was toggled on during the creation of that force it was not applied but that's okay because we're going to go in to simplify.

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Go into modify and select split, split face and we want to select the inside face of our tank and then the tool is going to be our plane.

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Once we say, okay, we can expand our model components and hide the construction folder and finish simplify.

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Now if we go back to our loads and once again we select hydrostatic pressure.

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We can begin by selecting the faces where the fluid will be applied and then you'll notice again, water is applied in this case.

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Now I want to select a surface point.

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Notice that I have nothing to select.

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If we don't have a vertex that we can use for the height of the fluid, we also have a points coordinate option.

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So even though we split the faces, Fusion 360 still wants to know exactly where the height of that fluid is.

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So if we bring this up to 100 mm, which is the location of our plane, we can now say okay.

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And our hydrostatic pressure has been applied.

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Now we have our hydrostatic pressure applied, gravity is turned on in the correct direction.

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We have a force on the top of this design and we have the bottom grounded.

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Everything can be solved.

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If you want to solve this simulation study, you can solve it either on the cloud or locally.

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Note that if you solve it on the cloud, it will require five cloud credits.

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To solve locally, it will simply use your local machine's resources.

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I'm going to solve this on the cloud and you don't need to solve it to go along with the study.

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But if you want to see the results, you can simply follow along and watch the results after they've been solved,

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to get an idea of how the hydrostatic pressure is going to affect this design.

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Once the simulation has solved, let's go ahead and close and let's take a look at the results.

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We can see here by the stress distribution that the majority of the stress is down around the fillet in the bottom corner.

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This is often why you would see a water tank or some sort of large fluid tank to be completely rounded on the bottom instead of having a flat bottom.

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And this fillet at corner.

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Also noting the fact that we fixed the bottom face of the design.

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The deformation can only happen in this area.

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If we go to a front view, I'm going to use some quick inspection tools, such as creating a slice plane using some of my default planes.

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In this case, I'm going to select XZ and then I'm going to pull it through the model.

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From here I'm going to animate the model and I'm going to take a look at what happens.

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You can see that the weight of the water is pushing down,

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and because we fix that face, what we're actually causing is that water to roll over that edge,

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because it's assuming that the bottom is completely fixed and there's nothing here that is going to stop the deformation of the tank.

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Keeping in mind that this deformation is not an actual deformation,

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but it's actually adjusted to a multiplication in this case 5 or 10 times the actual deformation.

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It doesn't necessarily mean that the design has completely failed.

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It just means that the deformation has been increased.

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So that way we can better understand the mode of deformation and where the stress is.

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Again, you're not required to solve the simulation study.

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But if you want to see the results of the hydrostatic pressure inside of this tank, it's a good idea to go ahead and solve it locally,

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but always make sure that you do save this before moving on.

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Now that we've taken a look at applying a force and a hydrostatic pressure,

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let's move back to our motorcycle rear set, which is the focus of our course.

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And let's talk about the other type of load that we want to look at, in this case a remote force.

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When we have something such as a remote force,

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the remote force is going to allow us to determine a force that's applied on the design at a point out in space.

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For our remote force for our secondary or bolted bracket we want to talk about applying it to the pivot points.

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When we do this we also want to make sure that we rotate the view and we bring this point a distance of 95 mm out in space.

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When we bring it out 95 mm this is going to be the point where the rider is going to be pushing down on the foot peg.

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We're going to change the units.

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In this case, we'll have pounds and we're going to change the structural load to be 350 pounds.

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That load is now applied to both pivot points inside of that bracket.

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This only happened in this bolted bracket.

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We have to go back to the other instance of the bracket that's not fixed in space.

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We need to repeat this.

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Keeping in mind that if we had applied these loads initially and then cloned our simulation model,

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they would already be in the model and we wouldn't have to repeat this process.

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I am going to manually move it out 95 mm, once again set it to pound force and set it to 350 pounds.

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There is one more iteration of this that I want to explore.

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So we're going to move back in to simplify and I'm going to clone the simulation model.

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I'm going to bring in study 1 static stress.

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Now I'm going to rename simulation model 3 to frame mount only.

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When I have the frame mount only.

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I need to make sure that I also remove that peg pivot.

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So we're going to select it, we're going to remove it and then we're going to finish simplify.

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You'll note that in frame mount only we now have a load case warning because the load was applied to something that is no longer in the design.

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So I'm going to modify this.

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I'm going to select the upper two mounting points,

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and this time instead of moving at 95 mm away, it needs to be a specific distance because it has to account for the pivot distance of that bracket.

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So we're going to move it out 110 mm.

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The load is going to be the same but note that the Y distance has actually changed.

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The Y distance is moved and you'll notice that it moved forward.

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I want to make sure that that Y distance is 0 and that the Z distance is 0 and notice that it puts it in relation to our coordinate system.

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What we actually need is that for it to be related to that pivot.

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So we need to put that -34 mm back in the Y and 50 mm back in the Z.

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To get the foot peg in the proper position.

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The force and the direction of the force is still accurate.

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So we can say, ok, go back to a home view.

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It is important to note that we no longer have a bolted connection,

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and that's because we cloned the original bracket and frame where we didn't have that bolted connection.

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This is intentional because it's less things for us to modify or remove.

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We simply had to change the location of that remote force.

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When we hover over it you can see the point out in space where the force is going to be applied and what it's applied to.

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At this stage let's make sure that we go back to a Home view and save this design before moving on to the next step.