MET 306 Lab 12. Creo Mathcad Prime Integration Level 8.5 only. Beam Deflection Problem

Transcription

1 Creo Mathcad Prime Integration Level 8.5 only Beam Deflection Problem Overall Concept: Produce a detail drawing that will act as a front end for displaying the exaggerated deflection (by 100 times) of a simply supported beam given beam dimensions and a loading. A table will be used as an input region. This data will then be taken into Mathcad where the moment of inertia of the beam, deflection and end angle slope will be calculated. This information will be communicated back to Creo where the model and ultimately the detail drawing will be updated to reflect the new input values. Page 1 of 6

2 Step 1. Build geometry that can be exercised. Use datum geometry for this purpose. Define four points locating the ends of the beam and the point load. PNT2 locates the load in the horizontal direction, PNT3 will locate the deflected location directly under PNT2. Initially locate PNT0 and PNT1 90 units from the profile plane. PNT2 is 36 units from PNT1 and PNT3 is 15 units under PNT2 (Normal to the horizontal plane and offset from PNT2). Using these points, create an External Sketch that will be used to define the deflection of the beam. Note that we need to define the slope at the ends. Use a spline with three points, the intermediate point being the location of the point load. Create a swept protrusion that defines the wide flange beam such that the bottom of the beam follows the external sketch. Page 2 of 6

3 Put a roller support under one corner and a triangular support under the other end. An equilateral triangle with a side length of 4 and a circle with a diameter of 4 are about the right proportions. Build a Force Arrow at the point of deflection on the beam. Make sure the force arrow does not change size when the beam bends, yet still will remain attached to the top of the beam. Step 2. Build a detail drawing (following page) that will be used to drive the geometry. Note that we are using a B size title block. Create parameters for all the input values. Create a Table for the input values. Use &parameter_name to display the value in the table. We do not need to include E as the material is always assumed to be A-36 steel. To specify the number of places in the table, change &parameter_name as follows: P should have no decimal places and will be &P[.0]. L and a display one place, height and width display two places and the web and flange thickness display three places. Center your text in the boxes in the vertical direction. The simple sketch in the upper right corner is just that; sketched geometry in drawing mode. Draw the beam, the supports and the Arrow. Dimension as shown and then change the numeric value (to show the symbol) and change the name to what is shown. The front view of the beam is a general view (.070 scale) and the dimensions are all shown dimensions. The cross sectional view was created with a cross section located 4 inches from the right end of the beam. This is an Area cross section. The dimensions are shown dimensions and are for reference Page 3 of 6

4 purposes only, not for construction purposes. To display the cross section, use geometry references and make sure the cross section plane faces front Step 3. Begin to set up relations to drive the model. L and a must be converted to inches in order to drive datum points 0 and 1. The beam dimensions must be mapped to the corresponding d values. Exercise all of your input values to see if the detail drawing updates like you expect. Step 4. Define additional parameters and set the units so Mathcad can receive the proper data. Add parameters TA, TB (Theta A is the slope angle at the left) and set the Unit of both of these to rad. Add parameter MOI (moment of inertia). This will be unit-less as Pro/E does not understand in^4 and this will be displayed in Pro/E for informational purposes only. Set the units for P to lbf, L and a to ft and the beam cross section dimensions to in. Step 5. Generate a Mathcad Prime worksheet that calculates the moment of inertia, the slope angles and deflection at point a as a function of the input values. Make sure you have included the proper units in the Input area. E will always be 29x10 6 psi. Multiply the slope angle and deflection by 100 as we wish to display an exaggerated value upon returning to Creo. Test your worksheet to make sure it is behaving properly. We cannot pass the moment of inertia directly back to Creo due to the unit issue. Simply create a new variable name that equal MOI/(1*in^4). This will strip off the units. Make sure to set the properties of values that are coming from and returning to Pro/E. Important: You cannot tag arithmetic expressions. Display a result and tag that. Step 6. Using methods found in Level 7, associate your Mathcad worksheet with Creo. You are still not done as you need to write relations that take the Mathcad values and map them to the Pro/E d values as you did in Level 7. Note that you will need to convert your TA and TB values (that are in radians) back to degrees when you write your relations. Page 4 of 6

5 Modify your drawing to include a note that reads MOMENT OF INERTIA = &MOI[.1] in^4. Place this directly under the table. You cannot use &MOI until it has been defined as a parameter, which is why we didn t include the note earlier. You will need to force a double regeneration (change one of your input values) to see this update. Modify your slope angles and deflection dimensions to include X 100. When you change your input values you will note that your cross section wants to dance around on the screen. This is because it is an area cross section and the overall size changes as a function of the curvature of the beam. Clean up your drawing so that it looks professional (arrows, witness lines etc.) Once there is an Analysis feature that references the Mathcad worksheet, any changes to Mathcad or Pro/E related to passing data back and forth from Creo to Mathcad will require redefinition of the Analysis feature. Simply do a redefine on the Analysis feature and hit the Next button until the Mathcad analysis dialog box appears. It is easy to add additional Dimensions or Paramaters for Creo to Mathcad and the Mathcad to Creo Outputs can also easily be added. Note you have access to the Mathcad worksheet at this time. Make sure you do a Compute and check on the Info before closing the dialog box. This is important: You may end up with relations that have lost some information when you do this so be sure you have screen captured and printed your relations before redefining the Analysis feature. If you choose to delete the Analysis feature and re-create it, you will see the Menu Manager for OBSOL RELS. Commnt Rels (Comment out the existing relations) so you don t lose them. Note that decreasing the load by a factor of 10 also decreases the deflection and angle by 10, as expected. Page 5 of 6

6 Other Hints: When initially defining the analysis feature, selecting Compute will cause the Mathcad file displayed on the screen to update its results. Note that the calculations are updated, NOT the input that is being passed from Creo. If you are struggling with incorrect results, did you redefine the Mathcad analysis feature and. Check to make sure all the input in the Creo Parametric to Prime area of the Prime Analysis dialog box is correct? Check to make sure all the input in the Prime to Creo Parametric area is correct (ie the Creo Parametric values are mapped to the correct variable name)? Check to make sure that you have properly defined all the parameters at the Creo model level? Checked your relation definitions? Step 7: Update your design using the following data: P lbs L 20 ft A 5 ft HEIGHT 14 in WIDTH 6 in WEB_T.25 in FLANGE_T.30 in Set the scale of the beam to.045 Set the scale of the cross section to.25 Print your B size detail drawing on A size paper Print your Mathcad worksheet. Note that the values in the worksheet will not reflect the input values above. Select Info - Relations and Parameters. Print this using the Print button on the top of the Browser window. There will probably be three pages produced. Step 8: Update your design once again using the following data: P lbs L 18 ft A 3 ft HEIGHT in WIDTH 5.78 in WEB_T.289 in FLANGE_T.50 in Print your B size detail drawing on A size paper Select Info - Relations and Parameters. Print this using the Print button on the top of the Browser window. There will probably be three pages produced. Things to check: Your Mathcad worksheet is professionally done with a layout similar to that specified for Lab 2, Level 8.5. Your updated detail drawing has all the details properly shown. End Level 8.5 Page 6 of 6