Shell Edge Contact

Chapter 49: Shell Edge Contact

49 Shell Edge Contact

Summary 994

Introduction 995

Modeling Details 995

Solution Procedure 1000

Results 1001

Modeling Tips 1003

Pre- and Postprocess with SimXpert 1004

Input File(s) 1035

Video 1036

MD Demonstration Problems

CHAPTER 49994

SummaryTitle Chapter 49: Shell Edge Contact

Features Case 1: In-plane glued edge deformable-deformable contactCase 2: General shell edge deformable-deformable contact

Geometry

Material properties Case 1: , ,

Case 2: ,

Analysis characteristics Case 1: Modal analysis using in plane glued edge contactCase 2: Quasi-static analysis using general shell edge contact

Boundary conditions • Case 1:Upper and lower half of plate are connected using glued edge contactFixed conditions at all four edgesIn-plane displacements restrained at all nodes except those nodes at the edges of the glued contact line

• Case 2:Edge-to-edge contact between two square tubesClamped condition at bottom edge of lower tube

Applied loads Case 2: Move top edge of top tube down two inches.

Element type 4-node shell elements

FE results Displacement Contours

10.0 m

10.0 m

y'

z'

z

z' z'

y'

y'

yx'

x'

x'

x

45o

Case 1: Modal Analysis of a Thick Rombic Plate

Units: m, N, s Units: in, lbf, s

Case 2: Diagonal Crushing of Square Tube

5 x 2 x 0.05

shell edge contact

shell edge contact

E 200GPa= 0.3= 8000 kg m3 =

E 2.1x1011psi= 0.3=

Seam

Case 1: Mode 1 134.18 Hz

995CHAPTER 49

Shell Edge Contact

IntroductionThe 3-D contact capability introduced in MD Nastran R2 supported a general node to surface contact in all translational degrees of freedom. The feature of shell edge to shell edge contact was added in the R3 release of MD Nastran. The following two cases are considered to demonstrate two different types of shell edge contact.

Modeling DetailsMD Nastran's solution sequences 103 and 400 are used to demonstrate the shell edge contact capability with the two test cases. The details of the finite element model, contact simulation, material, load, boundary conditions, and solution procedure for these two models are discussed below.

Case 1: Two equal parts of rhombic plate are meshed with different mesh densities of 16 x 32 and 20 x 40 CQUAD4 elements. These two parts do not share any node at their common edge as they are connected using in-plane glued edge contact. The FE model used for the modal analysis (SOL 103) shown in Figure 49-1 and the case control section part of the input is given below:

SUBCASE 1 METHOD = 1 BCONTACT = 1 SET 10 = 1,2,3,4,5,6 SET 20 = 137,182,213,280,327,593,600,639,703,744 SPC = 2 OMODE = 10 DISP(PLOT,PUNCH)=20

The modal analysis method to be used for extracting the eigenvalues is referenced by the METHOD option, and the associated contact table to be used is referenced by the BCONTACT option. The SPC option refers to the set of boundary conditions to be applied and the OMODE option identifies the list of modes to be extracted.

Case 1: Modal analysis of thick rhombic plate. This is a NAFEMS test case involving evaluation of natural frequencies of a fully clamped rhombic plate. The plate is divided into two equal parts in the vertical direction. These two parts are meshed with different mesh densities and then connected with in-plane glued edge contact.

Case 2: Diagonal crushing of two square tubes. This model demonstrate the capability of general shell edge contact by crushing the lower square tube with the upper square tube as a result of the edge contact between the two tubes.


CHAPTER 49996

Figure 49-1 FE Models used for Cases 1 and 2 of Shell Edge Contact

Case 2: The rectangular sides of each square tube are meshed using 5x10 CQUAD4 elements. The FE details for the SOL 400 analysis of Case 2 are given in Figure 49-1. The case control section part of the input for this model is given below:

SUBCASE 1 STEP 1 ANALYSIS = NLSTATIC NLPARM = 1 BCONTACT = 1 SPC = 2 LOAD = 1 DISPLACEMENT(SORT1,REAL)=ALL SPCFORCES(SORT1,REAL)=ALL STRESS(SORT1,REAL,VONMISES,BILIN)=ALL BOUTPUT(SORT1,REAL)=ALL

This section defines convergence controls via NLPARM, contact table and parameters via BCONTACT, applied displacements and loads via SPC and LOAD, and the displacements, stress, and contact results for the output file.

Material ModelingThe isotropic, Hookean elastic material properties of the deformable body for Case 1 are defined in the SI (international) system using the following MAT1 option:

MAT1 1 2.+11 .3 8000.

The MAT1 entry for Case 2 is given in the same system below:

MAT1 1 2.1+11 .3 1.

bsurf-1

bsurf-2

X

Y

Z

bsurf-1

bsurf-2

ZY X

Case 1 Case 2

997CHAPTER 49

Shell Edge Contact

Element ModelingBesides the standard options to define the element connectivity and grid coordinate location, the bulk data section contains various options with special relevance to nonlinear analysis. For the SOL 400 analysis of Case 2, the nonlinear extensions to the lower-order shell element, CQUAD4, are activated by using the PSHLN1 property option in conjunction with the regular PSHELL property option in the manner shown below:

PSHELL 1 1 .05 1 1PSHLN1 1 1 C4 DCT L

For the modal analysis of Case 1, regular CQUAD4 elements are defined using the following PSHELL option.

PSHELL 1 1 1. 1 1

Modeling ContactThe BCPARA option used for the Case 2 model is given below. It defines the number of bodies in contact, together with the maximum number of contact entities (e.g. patches), nodes on the periphery of the contact surfaces and bias factor. The general shell edge contact option is enabled by activating the beam to beam contact flag BEAMB.

BCPARA 0 NBODIES 2 MAXENT 400 MAXNOD 220 BIAS .95 BEAMB 1

The definition of the contact bodies consists of the BCBODY Bulk Data Entry which defines the deformable body including the body ID, dimensionality, type of body, type of contact constraints and friction, etc. while the BSURF identifies the elements forming a part of the deformable body. The following BCBODY entries are used for cases 1 and 2. Figure 49-2 identifies the contact bodies used in both these models.

BCBODY 1 3D DEFORM 1 0BSURF 1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 …

Figure 49-2 Contact Status Plot for Modal Analysis (Case 1)


CHAPTER 49998

To identify the interaction between the contact bodies, the BCTABLE Bulk Data Option is used. BCTABLE with ID 0 is used to define the touching conditions at the start of the analysis. This is a mandatory entry required in SOL 400 for contact analysis and it is flagged in the case control section through the optional BCONTACT = 0 option. The BCTABLE with ID 1 is used to define the touching conditions for later increments in the analysis, and it is flagged using BCONTACT = 1 in the Case Control Section.

A contact option, COPT, in BCTABLE allows more advanced control on how the contact bodies should interact with each other. COPT is defined using the formula COPT= =A+10*B+1000*C, where the terms A, B, and C are defined as follows:

A: the outside of the solid elements in the body

B (flexible bodies): the outside of the shell elements in the body

Note if B = 6 for both bodies in a contact combination, then nodes that separate from a body, cannot come in contact again in the current step or in subsequent steps unless a different flag is chosen for one of the bodies.

B (rigid bodies): the rigid surface

C (flexible bodies): the edges of the body

Note that C has no effect if beam-to-beam contact is not switched on (i.e., BEAMB is left as 0 on BCPARA).

The following BCTABLE entries are used for the SOL 103 analysis of Case 1:

BCTABLE 1 1 SLAVE 2 0. 0. 0. 0. 3 0 0 0 FBSH 1.+20 0. 0. 60 60

= 1: the outside will be in the contact description (DEFAULT)

= 1: both top and bottom faces will be in the contact description, thickness offset will be included (DEFAULT)

= 2: only bottom faces will be in the contact description, thickness offset will be included

= 3: only bottom faces will be in the contact description, shell thickness will be ignored

= 4: only top faces will be in the contact description, thickness offset will be included

= 5: only top faces will be in the contact description, shell thickness will be ignored

= 6: both top and bottom faces will be in the contact description, shell thickness will be ignored

= 1: the rigid surface should be in the contact description (DEFAULT)

= 1: only the beam/bar edges are included in the contact description (DEFAULT)

= 10: only the free and hard shell edges are included in the contact description

= 11: both the beam/bar edges and the free and hard shell edges are included in the contact description

999CHAPTER 49

Shell Edge Contact

It is important to note that the in-plane edge glued contact is activated by assigning value 60 for COPTS1 and COPTM1 in the 4th line of the BCTABLE option. The value 60 (B = 6) signifies that the edges are checked for contact without taking the shell thickness into account. Glued contact is defined by using a value of 3 for IGLUE in the 2nd line of the BCTABLE option. The value of IGLUE=3 allows moments to be transmitted across the contacting interface. JGLUE=0 in the 3rd field of the 3rd line ensures that glued nodes do not separate during the modal analysis. The contact status plot for Case 1 is presented in Figure 49-2.

For the SOL 400 analysis of Case 2, the regular shell edge contact option is activated by assigning value of 10010 (B=1 and C=10) for COPTS1 and COPTM1 in the following BCTABLE entries:

BCTABLE 0 1 SLAVE 2 0. 0. 0. 0. 0 0 0 0 FBSH 1.+20 0. 0. 10010 10010 MASTERS 1BCTABLE 1 1 SLAVE 2 0. 0. 0. 0. 0 0 0 0 FBSH 1.+20 0. 0. 10010 10010 MASTERS 1

B = 1 in the definition of the COPT flags indicates that the thickness and both faces are considered for contact and C = 10 indicates that the shell edges are included in the contact description.

Loading and Boundary ConditionsFor the SOL 103 analysis (Case 1), the boundary conditions are applied through the following SPC cards. No additional loads are applied for this analysis.

SPCADD 2 1 3SPC1 1 126 1 THRU 23SPC1 1 126 25 THRU 44… SPC1 3 123456 1 THRU 23SPC1 3 123456 44 65 86 107 128 149

For the SOL 400 analysis (Case 2), the loading and boundary conditions are applied with the following SPCD and SPC cards.

SPCADD 2 1 3FORCE 1 1 0. .57735 .57735 .57735SPCD 1 1 3 2. 2 3 2.SPCD 1 3 3 2. 4 3 2.…SPC1 1 123456 36SPC1 1 123456 391 THRU 400SPC1 3 123456 1 THRU 20

The loading and boundary conditions applied for Cases 1 and 2 are presented in Figure 49-3. For Case 1, the displacements for all nodes and along all edges as shown in Figure 49-3 ux uy z 0= = = uz x y 0= = =


CHAPTER 491000

except that the in-plane translation boundary condition for are not applied at the interface of the contact bodies so that they do not conflict with the in-plane glued edge contact constraints.

Figure 49-3 Loading and Boundary Conditions for Cases 1 and 2

Solution ProcedureThe modal analysis SOL 103 procedure for Case 1 is defined with the following EIGRL entry:

EIGRL 1 100. 500. 6 0 MASS

The six frequencies in the range 100 to 600 are requested through the above option.

The SOL 4 00 nonlinear procedure for Case 2 is defined through the following NLPARM entry:

NLPARM 1 10 PFNT 1 PV NO 0.1 0 0 0

The number of increments is provided in the 3rd field of the 1st line of NLPARM option. PFNT represents Pure Full Newton Raphson technique wherein the stiffness is reformed at every iteration. The value of KSTEP=1 along with PFNT option indicates that the stiffness matrix will not be updated between the convergence of a load increment and the start of the next load increment. PV indicates that the maximum vector component of the residuals will be checked for convergence. NO indicates that intermediate output will not be produced after every increment. The second line of NLPARM indicates that a tolerance of 0.1 will be used for convergence checking. The nonlinear procedure also deactivates Quasi-Newton, line search and cutbacks by assigning the value of 0 for MAXQN, MAXLS, and MAXBIS.

Case 1

Case 2

1001CHAPTER 49

Shell Edge Contact

ResultsFrequencies of 6 modes extracted from the modal analysis are indicated in the Table 49-1. It clearly shows that the in-plane glued edge contact can be successfully used to assemble parts with different mesh densities, since the predictions are within a 2% error. The mode shapes of the six modes for rhombic plate are presented in Figure 49-4.

Figure 49-4 Mode Shapes of Thick Rhombic Plate

Table 49-1 Comparison of Frequencies with NAFEMS Results

Mode Number

SOL 103Frequency

Hz

NAFEMSFrequency

Hz %Error

1 134.18 133.95 0.17

2 204.37 201.41 1.47

3 270.59 265.81 1.80

4 284.56 282.74 0.64

5 341.13 334.45 2.0

6 385.79 NA -

Mode 1: 134.18 Hz Mode 2: 204.37 Hz

Mode 3: 270.59 Hz Mode 4: 284.56 Hz

Mode 5: 341.13 Hz Mode 6: 385.79 Hz


CHAPTER 491002

Figures 49-5 and 49-6 demonstrate that the shell edge contact is properly detected as the top tube crushes the lower tube.

Figure 49-5 Contact Status Plots for Square Tubes with Shell Edge Contact

Figure 49-6 Original and Deformed Shapes of Square Tubes with Shell Edge Contact

Contact Status

50 % Load 100 % Load

Z-Displacement


1003CHAPTER 49

Shell Edge Contact

Modeling TipsThe most important aspect in the shell edge contact analysis is the COPT options introduced in BCTABLE. This gives more flexibility for users to define the interaction between different contact bodies (solid or shell or beam elements). Readers can observe the changes in results for the two cases presented in this chapter by removing the COPT options in BCTABLE.

It is also possible to define the COPT options in the BCPARA and BCBODY options. The options ITOPBM, ITOPSH, and ITOPSL in the BCPARA option and COPTB in the BCBODY option can be used to define the same COPT option in cases where BCTABLE is not used in the model with BCONTACT=ALLBODY option. This is recommended as an exercise for the readers.

It is important to remember that the general shell edge contact capability is activated by setting the beam to beam contact flag option BEAMB to 1 in BCPARA entry.


CHAPTER 491004

Pre- and Postprocess with SimXpertThis example will take you through Case 2 of the Shell Edge Contact Cases. The required input file can be downloaded by clicking the nug_49b.dat link in the Input File(s) section of this document.

Specify the Model Units

a. Tools: Options

b. Select Units Manager

c. For Basic Units, specify the model units

Length = mm; Mass = kg; Time = s; Temperature = kelvin, Force = N

d. Click OK

a

bc

da

1005CHAPTER 49

Shell Edge Contact

Import FE Mesh

a. File

b. Select Import

c. Select Nastran

d. Select nug49_mesh.bdf

e. Click Open

a

b

c

d

e


CHAPTER 491006

Set Model View

a. View

b. Select Model Views

c. Select Front

d. Select Fill

a

b

c

d

1007CHAPTER 49

Shell Edge Contact

Define Material

a. Materials and Properties tab

b. Material, select Isotropic

c. Young’s Modulus: enter 2.1e11

d. Poisson’s Ratio: enter 0.3

e. Click OK

ab

c

d

e


CHAPTER 491008

Define Property Data

a. Materials and Properties tab

b. 2D Properties, select Shell

c. Entities: select PSHELL_nug49_mesh.bdf

d. Material: select Iso_1

e. Part thickness: enter 0.05

f. Click Advanced

a

b

c

de

f

c

d

1009CHAPTER 49

Shell Edge Contact

Define Property Data (continued)

a. Click Non Linear

b. Membrane material, select Iso_1

c. Bending material: select Iso_1

d. Analysis type: select IS

e. Corner elements keyword: select C4

f. Element structural behaviour: select DCT

g. Integration scheme: select L

h. Click OK

abcd

ef

g

h

b c


CHAPTER 491010

Define Contact Body for Lower Part

a. LBCs tab

b. Contact, select Deformable Body

c. Name: enter body_lower

d. Type: select Deformable Surface

e. Pick Entities: select 200 Elements

f. FEM filters: select Pick Elements

g. Select elements from lower part of shell

h. Click OK

a

b

cd

ef

g

h

1011CHAPTER 49

Shell Edge Contact

Define Contact Body for Upper Part

a. LBCs tab

b. Contact, select Deformable Body

c. Name: enter body_upper

d. Type: select Deformable Surface

e. Pick Entities: select 200 Elements

f. FEM filters: select Pick Elements

g. Select elements from upper part of shell

h. Click OK

a

b

cd

e

f

g

h


CHAPTER 491012

Define Contact Table

a. LBCs tab

b. Contact, select Table

c. Click Deactivate All

d. Touching Condition for body 1: set to 2

e. Distance Tolerance: enter 0

f. Individual Contact Detection: select Double Sided

g. Individual Slave Option Flag: select 100010

h. Individual Master Option Flag: select 10010

i. Click OK

a

b

cd

e

f

gh

i

1013CHAPTER 49

Shell Edge Contact

Define Boundary Conditions

a. LBCs tab

b. Constraints, select Fixed

c. Name: enter fix-z

d. Entities: select nodes at the top edge of body_upper

e. Click OK

ab

c

d

e

d


CHAPTER 491014

Define Boundary Conditions (continued)

a. LBCs tab

b. Constraints, select General

c. Name: enter disp-z

d. Entities: select nodes at the top edge of body_upper

e. Tz: select 2.0

f. Click OK

a

b

c

d

e

f

d

1015CHAPTER 49

Shell Edge Contact

Analysis Setup

a. Model Browser: right click FileSet (nug49_mesh)

b. Select Create new Nastran job

c. Name: enter ch49b

d. Solution Type: select SOL400

e. Solver Input File: select ch49b.bdf

f. Uncheck Create Default Layout

g. Click OK

ab

c

de

f

g


CHAPTER 491016

Analysis Setup (continued)

a. Model Browser: nug49_mesh.bdf, ch49b, right click Load Case

b. Select Create Global Loadcase

c. Click OK

ab

c

1017CHAPTER 49

Shell Edge Contact


a. Model Browser: nug49_mesh.bdf, ch49b, right click Loads/Boundaries

b. Select Select Contact Table

c. Selected BCT Table, select BCTABLE_1

d. Click OK

e. Model Browser: nug49_mesh.bdf, ch49b, right click Load Case

e. Select Create Loadcase

g. Name (Title): enter subcase-1

h. Click OK

a

b

c

d

e

f

g

h


CHAPTER 491018


a. Model Browser: Load Cases, subcase-1, double click Load Case Control

b. Select Subcase Nonlinear Static Parameters

c. Stiffness Update Method: select PFNT

d. Uncheck Use Default Tolerance Setting

e. Check Load Error, for Load Tolerance: enter 0.01

e. Check Vector Component Method

g. Intermediate Output Control: select Yes

h. Click Apply

i. Click Close

a

bc

d

e

f

g

h

i

e

1019CHAPTER 49

Shell Edge Contact


a. Model Browser: double click Load Case Control

b. Select Stepping Procedure Parameters

c. Number of Steps: enter 10

d. Click Apply

e. Click Close

a

bc

d

e


CHAPTER 491020


a. Model Browser, subcase-1, right click Load/Boundaries

b. Select Select Lbcs

c. From Model Browser with control key and mouse, select fix-z and disp-z

d. Click OK

a

b

c

d

c

1021CHAPTER 49

Shell Edge Contact


a. Model Browser, subcase-1, right click Load/Boundaries

b. Select Contact Table

c. Selected BCT Table, select BCTABLE_1

d. Click OK

a

b

c

d

c


CHAPTER 491022


a. Model Browser, subcase-1, right click Output Request

b. Select Nodal Output Requests

c. Select Create Displacement Output Request

d. Check Suppress Print

Click OK

a

b

c

d

e

1023CHAPTER 49

Shell Edge Contact



b. Select Nodal Output Requests

c. Select Create Contact Output Request


Click OK

ab

c

d

e


CHAPTER 491024



b. Select Elemental Output Requests

c. Select Create Nonlinear Stress Output Request


e. Click OK

a

b

c

d

e

1025CHAPTER 49

Shell Edge Contact


a. Model Browser, ch49b, double click Solver Control

b. Contact Control Parameters, select Contact Detection Parameters

c. Distance Tolerance, enter 0

d. Bias on Distance Tolerance: enter 0.9

e. Click Activate 3D Beam-Beam Contact

f. Click Apply

g. Click Close

a

b

cde

f

g


CHAPTER 491026


a. Model Browser, ch49b, double click Solver Control

b.Select Output File Properties

c. Nastran DB Options, select Master/DBALL

d. Binary Output: select OP2

e. Click Apply

Click Close (not shown)

a

b c

d

e

1027CHAPTER 49

Shell Edge Contact

Analysis

a. File, click Save

b.Model Browser, right click ch49b

c. Select Run

d. Click Save (after completion of job)

e. File, click New

ab

c

de


CHAPTER 491028

Postprocessing

a. File, click Attach Results

b.File path: select MASTER

c. Attach Options: select Both

d. Click OK

a

b

c

d

1029CHAPTER 49

Shell Edge Contact

Postprocessing (continued)

a. Results tab

b.Results: select Deformation

c. Deformed display scaling: select True

d. Click Plot Data tab

e. Plot attribute, Plot type, Deformation

f. Result Cases, select last increment

g. Result Type, select Displacements, Translational

h. Click Update

ab

c

d

e

f

gh


CHAPTER 491030


a. State plot property editor

b.Check Animate

c. Result Cases, select SC1_Step1

d. Result Type, select Displacements, Translational

e. Click Update

a

b c

de

1031CHAPTER 49

Shell Edge Contact


a. Click Pause icon

a


CHAPTER 491032


a. Results tab

b.Results: select Fringe

c. Check Animate

d. Result Cases, select SC1_Step1

e. Result Type, select contactforce,Normal

f. Click Fringe tab

g. Element edge display, Display, select Element edges

h. Click Label attributes tab

i. Select appropriate color for labels

j. Click Update

a

b

c d e

f

g

h

i j

1033CHAPTER 49

Shell Edge Contact



CHAPTER 491034


a. Click Pause icon

b.Click Plot Data tab

c. Result Type, select Nonlinear Stresses

d. Derivation, select X Component

e. Click Update

a

b

cd

e

1035CHAPTER 49

Shell Edge Contact


Input File(s)File Description

nug_49a.dat MD Nastran input for modal analysis of rhombic plate (Case 1)

nug_49b.dat MD Nastran input for diagonal crushing of square tubes (Case 2)

http://www.mscsoftware.com/doc/nastran/mdug/input_files/ch049/nug_49a.dat

http://www.mscsoftware.com/doc/nastran/mdug/input_files/ch049/nug_49b.dat


CHAPTER 491036

VideoClick on the image or caption below to view a streaming video of this problem; it lasts approximately nine minutes and explains how the steps are performed.

Figure 49-7 Video of the Above Steps

Contact Status


http://www.mscsoftware.com/training_videos/mdug/ch049/2010/ch049.swf

http://www.mscsoftware.com/training_videos/mdug/ch049/2010/ch049.swf

Date post:	10-Apr-2015
Category:	Documents
Upload:	dan-wolf
View:	263 times
Download:	1 times

Shell Edge Contact

Documents