Defining loads

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In this video, you’ll

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convert an analysis diagram into applied loads,

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convert a written description of load scenarios into applied loads,

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apply loads accurately to model,

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select the appropriate vector,

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replace non-modeled bodies with remote forces,

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and differentiate structural constraints and loads.

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It is important to know how your design reacts under normal and excessive working conditions.

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Structural loads are forces applied to a part or assembly

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during operation and can cause stresses and displacements in components.

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There are several different loads you can apply to a part.

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Force loads apply a force to change the state or direction of motion of a body.

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Pressure loads apply a uniformly distributed load normally to a defined area.

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Moment loads apply a twisting load that simulates the effect of torque on a model.

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Bearing loads apply a load that simulates the effects of cylindrical bodies pushing on one another.

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Remote force loads apply a point load to simulate the effects of a force

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applied from a point in space that is not on the model.

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To begin, open Defining Loads.png.

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Review the analysis diagram.

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In it, a 500 newton (N), uniformly distributed load acts on the top face of the part.

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A bearing load of 1 kilonewton (kN) acts along one arm of the part,

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and another bearing load of 1 kN acts to the right of the part.

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Gravity is also acting down on the part at 9.81 meters-per-second-squared (m/s²),

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and the entire part is accelerating axially at 4m/s².

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To convert these load scenarios into Fusion 360,

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open the file Defining Loads.f3d in the Simulation workspace.

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From the Browser, under Study 1-Static Stress, select Load Case1.

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Then, expand Loads.

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The first load to implement is gravity.

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Right-click Gravity and, from the shortcut menu, select Unsuppress.

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By default, standard gravity is applied in the negative Y direction.

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In the canvas, a yellow arrow displays at the center of the global coordinate system

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to indicate when gravity is enabled.

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Gravity is expressed in units of length per (unit time)².

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In this case, the gravitational direction is appropriate.

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If it is not correct, you can redefine it.

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From the Browser, right-click Gravity and select Edit Gravity.

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In the Edit Gravity dialog, next to Direction Type,

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you can select Vectors (x, y, z) to change the direction.

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For now, close the dialog.

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Next, apply a uniformly distributed Force load acting down on the top face of the part.

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From the Toolbar, expand Loads and select Structural Loads.

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In the Structural Loads dialog, ensure that the Type is set to Force.

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Force loads are applied to faces, edges, and vertices.

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In the canvas, select the top face of the part.

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Then, back in the dialog, in the Magnitude field, enter 500.

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Notice that the arrows indicate which direction the force is being applied.

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In this example, they are perpendicular to the surface and in the downward direction, which is correct.

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Click OK.

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Now, it is time to place a bearing load of 1kN acting along one arm of the part.

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From the Toolbar, expand the Loads drop-down and again select Structural Loads.

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In the dialog, expand Type and select Bearing Load.

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Bearing loads apply to single or multiple faces and apply a load

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that simulates the effects of cylindrical bodies pushing on one another.

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Be aware that the face must be either fully or partially cylindrical,

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and it may be an exterior or interior face.

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In the canvas, select the upper-right cylindrical face.

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A controller displays.

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You can use this to specify the direction of the load.

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You can also specify the angle in the direction.

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Next to Direction Type, select Reference.

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Next to Direction Reference, click the selection tool.

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Now, back in the canvas, select an edge or perpendicular face to guide the direction of the force.

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Then, in the dialog, in the Magnitude field, enter 1000 N, and then click OK.

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Now, apply a second bearing load to the bottom pin, this time acting to the right of the part.

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Again, open the Structural Loads dialog and change the Type to Bearing Load.

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In the canvas, choose the lower-right cylindrical face.

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In the dialog, next to Direction Type, select Vectors (x, y, z).

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In the Fx field, enter 1000.

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This places a 1kN load in the direction of X.

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Click OK.

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The final force to apply is a general acceleration acting upon the entire part axially.

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From the Toolbar, expand Loads and select Linear Global Loads.

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The Linear Global Load dialog displays.

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Global loads affect all the parts or bodies of the Simulation model,

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and only one global load can be applied per study.

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Linear acceleration loads are loads such as the forces acting on a drag racer

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while it is accelerating in a straight-line direction.

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In the canvas, select the front face of the part,

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perpendicular to the direction that you wish to accelerate,

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to specify the direction of the global load.

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In the dialog, under Acceleration Components, in the Magnitude field, enter 4m/s².

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Click OK.

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Now, all loads from the analysis diagram have been converted to applied loads in Fusion 360.

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Save the file.