S6-1 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation SECTION 6 TRAFFIC SIGNAL POLE. - презентация

1 S6-1 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation SECTION 6 TRAFFIC SIGNAL POLE

2 S6-2 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation SECTION 6 TRAFFIC SIGNAL POLE

3 S6-3 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation SECTION 6 TRAFFIC SIGNAL POLE n Topics covered in this case study: u Material properties u Nastran CBEAM element u Fields

4 S6-4 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation n Problem Description u A traffic signal pole supports the signal at one end and is attached to the vertical pole at the other end. It has a circular tube cross section. The loading on the signal pole is 200 lbs. n Analysis Objective u Determine stresses in the pole due to traffic signal loading. The maximum stress must be below the yield point of the pole material. CASE STUDY: TRAFFIC SIGNAL POLE

5 S6-5 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation n Traffic signal pole specifications u Length: 20 ft u Cross section: circular tube u Outer radius: 4 tapering down to 3 u Inner radius: 3.5 tapering down to 2.5 u Material: Steel with 50,000 psi yield strength SECTION 6 TRAFFIC SIGNAL POLE

6 S6-6 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation Create the signal pole geometry CREATE SIGNAL POLE GEOMETRY

7 S6-7 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation Examine the parametric direction for the curve CREATE SIGNAL POLE GEOMETRY (cont.)

8 S6-8 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation n Methods for Creating Curves WORKING WITH CURVES

9 S6-9 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation n Methods for Creating Curves WORKING WITH CURVES (cont.)

10 S6-10 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation n Methods for Creating Curves WORKING WITH CURVES (cont.)

11 S6-11 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation n Other Actions for Curves WORKING WITH CURVES (cont.)

12 S6-12 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation n Editing Curves WORKING WITH CURVES (cont.)

13 S6-13 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation n Showing Curves WORKING WITH CURVES (cont.)

14 S6-14 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation n Transforming Curves WORKING WITH CURVES (cont.)

15 S6-15 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation n Associate/Disassociate Curves u You can only associate curves to curves or surfaces which are within the global model tolerance u Associated curves may be used to guide the interior meshing of an entity through mesh seeding u Curves can be associated with other curve and surface types of geometry WORKING WITH CURVES (cont.)

16 S6-16 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation n Now mesh the curve to generate grid points and elements n Use mesh seeds to control the mesh MESHING THE GEOMETRY

17 S6-17 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation Create uniform mesh seeds MESHING THE GEOMETRY (cont.)

18 S6-18 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation Mesh the curve to create 1D elements MESHING THE GEOMETRY (cont.)

19 S6-19 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation n Creating Material Properties u So far in the case studies we have been creating isotropic materials such as steel and aluminum u Patran supports a number of material types as shown on the next page MATERIAL PROPERTIES

20 S6-20 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation u IsotropicIsotropic structural material (MAT1) u 2D Orthotropic2-Dimensional orthotropic material (MAT8) u 3D Orthotropic3-Dimensional orthotropic material (MAT9) u 2D Anisotropic2-Dimensional anisotropic (MAT2) u 3D Anisotropic3-Dimensional anisotropic (MAT9) u CompositeVarious composite material models n Material Types MATERIAL PROPERTIES (cont.)

21 S6-21 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation MATERIAL PROPERTIES (cont.) n The creation of isotropic materials is covered in this section. n The creation of composite materials is covered in a later section

22 S6-22 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation n Material Property Definitions MATERIAL PROPERTIES (cont.)

23 S6-23 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation n Material Property Definitions (cont.) HomogeneousMaterial properties are independent of the location within the material. IsotropicMaterial properties do not change with the direction of the material. The three properties needed to completely describe an isotropic material are E,, and G (shear modulus). Only two are independent. MATERIAL PROPERTIES (cont.)

24 S6-24 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation n There are three ways to create material properties in PATRAN u Manual Input u Materials Selector (MVision) u Externally Defined MATERIAL PROPERTIES (cont.)

25 S6-25 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation How to create an isotropic material by manual input MATERIAL PROPERTIES (cont.)

26 S6-26 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation n NASTRAN entry for isotropic materials MATERIAL PROPERTIES (cont.)

27 S6-27 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation n Create material properties for this case study u Following properties are given for the signal post material: l E = 29 x 10 6 psi = 0.3 l Yield strength = 50 ksi MATERIAL PROPERTIES (cont.)

28 S6-28 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation Create an isotropic material named steel MATERIAL PROPERTIES (cont.)

29 S6-29 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation Define material strength properties MATERIAL PROPERTIES (cont.)

30 S6-30 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation CBAR CBEND CBEAM SELECT ELEMENT TYPE

31 S6-31 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation n CBEAM Element Overview u Connected to two grid points u Force components: l Axial force P l Shear forces in 2 planes V 1 and V 2 l Bending moments in 2 planes M 1 and M 2 l Total torque T l Warping torque T w u Displacement components: u i, i, and THE CBEAM ELEMENT

32 S6-32 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation n CBEAM Element Overview (cont.) u The CBEAM element includes all capabilities of the CBAR element plus several optional capabilities that include: l The cross-sectional properties may be specified at up to nine interior points and also at both ends l The neutral axis and shear center axis need not be coincident l The effect of cross-sectional warping on the torsional stiffness l The effect of taper on the transverse shear stiffness (shear relief) l The nonstructural mass center of gravity can be offset from the shear center THE CBEAM ELEMENT (cont.)

33 S6-33 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation n The CBEAM Entry THE CBEAM ELEMENT (cont.)

34 S6-34 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation n The CBEAM Entry (cont.) THE CBEAM ELEMENT (cont.)

35 S6-35 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation n The CBEAM Entry (cont.) THE CBEAM ELEMENT (cont.)

36 S6-36 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation THE CBEAM ELEMENT (cont.)

37 S6-37 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation n The CBEAM Element Properties THE CBEAM ELEMENT (cont.)

38 S6-38 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation THE CBEAM ELEMENT (cont.) n The CBEAM Element Properties

39 S6-39 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation THE CBEAM ELEMENT (cont.) n The CBEAM Element Properties

40 S6-40 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation THE CBEAM ELEMENT (cont.) n The CBEAM Element Properties

41 S6-41 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation n Shear Relief Coefficients S1 and S2 u The shear relief coefficient accounts for the fact that in a tapered flanged beam the flanges sustain a portion of the transverse shear load. This situation is illustrated below: THE CBEAM ELEMENT (cont.)

42 S6-42 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation n Shear Relief Coefficients S1 and S2 (cont.) u The value of the shear coefficient for a tapered beam with heavy flanges that sustain the entire moment load may then be written as u See the MSC.Nastran Reference Manual for further details on the shear relief coefficients. THE CBEAM ELEMENT (cont.)

43 S6-43 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation u A twisting moment m is applied to a beam and the beam twists u For a beam with a circular cross section, plane sections remain plane after twisting u For a beam with a non-circular cross section, plane sections do not remain plane, but warp. This behavior is described by the differential equation below: THE CBEAM ELEMENT (cont.)

44 S6-44 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation u The first term in the equation is called the twisting torque. The second term in the equation is called the warping torque. m is the total torque. u In order to model the warping effect, the user must enter the warping coefficients on the PBEAM entry and specify two scalar points on the CBEAM entry. THE CBEAM ELEMENT (cont.)

45 S6-45 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation n Neutral Axis Offset from Shear Center (N 1, N 2 ) n The N1 and N2 fields on the PBEAM entry allow the user to specify the neutral axis offset from the shear center. THE CBEAM ELEMENT (cont.)

46 S6-46 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation n The CBEAM properties can be alternatively specified using the PBEAML entry. THE CBEAM ELEMENT (cont.)

47 S6-47 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation n CBEAM element internal forces and moments THE CBEAM ELEMENT (cont.)

48 S6-48 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation n CBEAM element internal forces and moments in plane 1 and plane 2 THE CBEAM ELEMENT (cont.)

49 S6-49 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation n Use the CBEAM element n The outer radius of the pole tapers from R = 4.0 to R = 3.0 n The inner radius of the pole tapers from R = 3.5 to R = 2.5 MODELING THE TAPERED SIGNAL POLE

50 S6-50 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation n The linearly varying outer and inner radii of the beam will be modeled by using Fields. n Fields in PATRAN are used to define variations in u Loads u Boundary Conditions u Material Properties u Element Properties n There are three types of fields: u Spatial Fields u Non Spatial Fields u Material Property Fields n Use Spatial Fields to model the beam tapers in this case study. FIELDS

51 S6-51 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation Create a field for the taper in beam outer radius from 4 to 3 CREATING FIELDS

52 S6-52 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation Create a second field for the taper in beam inner radius from 3.5 to 2.5 CREATING FIELDS (cont.)

53 S6-53 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation Verify the two fields by plotting them CREATING FIELDS (cont.)

54 S6-54 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation Create 1D element properties CREATING ELEMENT PROPERTIES

55 S6-55 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation Input properties CREATING ELEMENT PROPERTIES (cont.)

56 S6-56 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation Select the steel material created earlier CREATING ELEMENT PROPERTIES (cont.)

57 S6-57 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation Enter the beam orientation vector CREATING ELEMENT PROPERTIES (cont.)

58 S6-58 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation Select the circular tube section from the Beam Library and name it circular tube section CREATING ELEMENT PROPERTIES (cont.)

59 S6-59 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation Enter R1 and R2 by selecting the fields created earlier CREATING ELEMENT PROPERTIES (cont.)

60 S6-60 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation Select curve 1 and click calculate/display to show cross section at one end of curve CREATING ELEMENT PROPERTIES (cont.)

61 S6-61 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation Slide the parametric location dial from End A to End B and click Calculate/Display to view cross section at the other end of curve CREATING ELEMENT PROPERTIES (cont.)

62 S6-62 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation Select OK to accept the beam library section. Select OK to accept the input properties. Click Apply to create the element property CREATING ELEMENT PROPERTIES (cont.)

63 S6-63 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation Change from 1D to 3D display to visually inspect the cross section CREATING ELEMENT PROPERTIES (cont.)

64 S6-64 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation 3D display of tapered beam CREATING ELEMENT PROPERTIES (cont.)

65 S6-65 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation Create the boundary condition CREATE BOUNDARY CONDITION

66 S6-66 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation Constrain all six degrees of freedom CREATE BOUNDARY CONDITION (cont.)

67 S6-67 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation Select the end point CREATE BOUNDARY CONDITION (cont.)

68 S6-68 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation Finish creating the boundary condition CREATE BOUNDARY CONDITION (cont.)

69 S6-69 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation Create a concentrated force of 200 lbs downward CREATE LOADS

70 S6-70 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation Apply the force to the end of the beam CREATE LOADS (cont.)

71 S6-71 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation The load is applied. CREATE LOADS (cont.)

72 S6-72 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation Set up a static analysis run in NASTRAN PERFORM ANALYSIS

73 S6-73 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation Set up the output request: 1. Select Subcases 2. Select the Default subcase 3. Select Output Requests 4. Select Element Forces to add this to the Output Request Box 5.OK, Apply, and Cancel. REQUEST FOR ADDITIONAL OUTPUT

74 S6-74 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation Select Apply to submit the job to NASTRAN PERFORM ANALYSIS (cont.)

75 S6-75 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation Read the NASTRAN results into PATRAN ATTACH RESULTS

76 S6-76 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation Plot the deformation PLOT RESULTS

77 S6-77 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation Plot the maximum combined axial and bending stresses. Plot it again with averaging domain set to none. PLOT RESULTS (cont.)

78 S6-78 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation Plot the minimum combined axial and bending stresses. Plot it again with averaging domain set to none. PLOT RESULTS (cont.)

79 S6-79 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation n The maximum stress according to PATRAN is 2,307 psi. Compare this to the NASTRAN.f06 file shown below: EXAMINE THE F06 FILE

80 S6-80 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation n Use the NASTRAN element force output from the.f06 file to compute stresses by hand. Axial Stress f a = P/A = 0 psi Tens. Bending Stress f b = MC/I = 48000(4.0)/ = 2,307.6 psi Comp. Bending Stress f b = MC/I = 48000(-4.0)/ = -2,307.6 psi n The computed stresses do agree with the NASTRAN stress output on the previous page. EXAMINE THE F06 FILE (cont.)

81 S6-81 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation CASE STUDY SUMMARY n Traffic signal pole stresses based on preliminary finite element analysis are well below the yield point of the material. n Further analysis may consider different types of loading and crippling of circular cross section.

82 S6-82 NAS120, Section 6, May 2006 Copyright 2006 MSC.Software Corporation EXERCISE Perform Workshop 7 Tapered Plate in your exercise workbook.