柔体(含刚柔混合)动力学分析_练习

Align Connecting Rod and Crank
• • Select “Revolute - conrod-brg:2 To crank:1” In the Details view, select “Mobile > Initial Position: Override” A new “Mobile Coordinate System” will be added as a sub-branch.
Automatically Create Joints
• Right-click on “Connections” and select “Create Automatic Joints” • Joints will automatically be detected based on the proximity of faces to one another. • Although Joints have automatically been generated, it is always a good idea to verify the created joints. In this example, some joints are not required, so they will be deleted; other joints need to be modified; lastly, additional joints will be manually generated.
柔体动力学分析_练习 柔体动力学分析 练习
Overview
In this example, a Flexible Dynamic Analysis will be performed on a part of an engine assembly:
– Both Rigid Dynamic and Flexible Dynamic Analyses will be solved and compared – Joint definition and loading will be covered – For the Flexible Dynamic Analysis, stresses in the connecting rod are of interest, so only that part will be flexible – Assembly is from an Autodesk Inventor sample model – Steps necessary to perform this workshop will be shown with bullet points
• The above joints are not required, so they need to be removed. • Change the following joints from “Revolute” type to “Fixed”:
– Revolute - conrod:1 To conrod-brg:2 – Revolute - conrod-cap:1 To conrod-brg:1
Create Joint for Bearing and Crank
• Select the inner cylindrical surface of “conrod-brg:1” and the cylindrical surface of “crank:1”. From the Context Toolbar, select “Body-Body > Revolute” A revolute joint has now been defined for the two parts. Presently, the two parts are misaligned. This will be corrected later on.
Overview of Joints to be Defined
• For this model, 9 Body-to-Body Joints will be defined (shown on bottom left) to provide constraints on movement between the 9 bodies • 2 Body-to-Ground Joints will be defined on the Crank and Bore (shown on bottom right)
•
Created Body-to-Ground Joint for Crank
• Select the end surface of the “crank:1” part and choose “Body-Ground > Revolute” from the Context Toolbar This will define a body-to-ground joint for the crank.
Assembly shown here is from an Autodesk Inventor sample model
Open Simulation Dale.wbdb” • From the Project page, open the “Model” Simulation Database • The assembly has already been imported. Note that the assembly is initially misaligned. This will be corrected during the course of the workshop. • Example the parts in the “Geometry” branch. Note that all the parts are set to be rigid for now, and some parts that are unnecessary have been supressed.
Created Body-to-Ground Joint for Bore
• Select the outer cylindrical surface of “bore:1” and choose “Body-Ground > Fixed” from the Context Toolbar This will ground the bore part.
Delete Unnecessary Joints
• Select and right-click to “Delete” the following joints:
– Revolute - bore:1 To conrod-brg:2 – Fixed - conrod:1 To conrod-brg:1 – Fixed - conrod-cap:1 To conrod-brg:2
• Select the above two Joints, then in the Details view, change “Type: Revolute” to “Type: Fixed”
Modify Created Joints
• • Select “Fixed - conrod:1 To conrod-cap:1” In the Context Toolbar, activate “Body Views” Notice that with Body Views on, surfaces for each of the two parts in the Joint can more easily be viewed and selected. Right now, only 1 set of mating surfaces are in the Joint. The next step will add the other set of mating surfaces to the Joint. In the Details view, select “Reference > Scope: 1 Face”. Ctrl-select the additional surface on the other side for “conrod:1”. Ensure that both surfaces are selected, then click on “Apply” In the Details view, select “Mobile > Scope: 1 Face”. Ctrl-select the additional surface on the other side for “conrod-cap:1”. Ensure that both surfaces are selected, then click on “Apply”
Align Connecting Rod and Crank (cont’d) ’
• • Select “Mobile Coordinate System” In the Details view, select “Geometry: Click to Change”. Select the cylindrical surface used in part of the Joint definition, as circled on the right. Click on “Apply” The Mobile Coordinate System has now been changed to be aligned with the mating part of the crank.
•
•
•
Create Joint for Piston and Bore
• Select the inner cylindrical surface of “bore:1” and the outer cylindrical surface for “piston:1” • From the Context Toolbar, select “Body-Body > Cylindrical” A Joint is now defined between the piston and bore.