Lecture 5
Solving Truss Problems
with ABAQUS
Lecture 5: 2D Truss Structures
Introduction: In this lecutre you will learn to use the 2-D Truss
element in ABAQUS.
Physical Problem: A power transmission tower is a common
example of a structure that is made up of only truss members.
These towers are actually 3-D structures, but for the sake of
simplicity we will take a cross-sectional face of the tower. The
tower is mainly subjected to loading in the vertical direction
due to the weight of the cables. Also it is subjected to forces due
to wind. In this example we will consider only loading due to
the weight of the cables, which is in the vertical direction.
Lecture 5: 2D Truss Structures
Problem Description:
The tower is made up of trusses.
Units: Use S.I. units ONLY
Geometry: the cross sections 6.25e-3 m^2
Material: steel with modulus of elasticity
E=200 GPa.
Boundary conditions: shown in the figure.
Loading: shown in the figure
Objective:
To determine deflection at each joint.
To determine stress in each member.
To determine reaction forces at the base.
Lecture 5: 2D Truss Structures
1 Start ABAQUS/CAE
On the Windows Main Screen click Start>Programs>ABAQUS 6.10
>ABAQUS CAE
On the pop up start window, choose with Standard/Explicit Model
Lecture 5: 2D Truss Structures
2 Create Part
Click
（create part）at the left tooling zone
or in the main menu, choose part >create.
The right window comes up。
Name：change the part name to truss2D
Modeling Space：2D Planar
Base Feature：wire
Approximate size：20
click：Continue
Lecture 5: 2D Truss Structures
On the left of the pop-up window is the tooling zone for
drawing
Click
model
（create lines：connected），draw line to finish the
Click the middle key of the mouse to quit the drawing line
mode. Click the middle key again to quit the drawing
environment.
The truss structure is created
Lecture 5: 2D Truss Structures
3 Create Material
On the left tooling zone,
click
（create material）
，a window ‘Edit Material ‘
pops up
Lecture 5: 2D Truss Structures
input ‘Steel’ as the material
name
Click
Mechanical>Elasticity>Elastic ,
then input 200e9 as the Young’s
modulus
Click OK
Lecture 5: 2D Truss Structures
4 Create Section
Click
(create section),
Select ‘Beam’for ‘Category’
and ‘Truss’ for ‘Type’. Give
the section name as ‘Section1’.
In the ‘Edit Section’window,
select ‘steel’ as the material,
input 6.25e-3 for ‘crosssectional area, and click ‘OK’
Lecture 5: 2D Truss Structures
5 Assign Section to Elements
Click
（Assign Section），
select the elements to assign section
In the ‘Edit Section Assignment ‘,
select ‘Section-1’, and click OK。
Lecture 5: 2D Truss Structures
6 Define Assembly
In the ‘Module’, select Assembly
In the tooling zone, select
（Instance Part），or in the main
menu select Instance>Create.
In the ‘Create Instance’window，
Select the created part，Choose
Instance Type：Dependent， click OK。
Lecture 5: 2D Truss Structures
7 Define Step
In the ‘Module’, select
Step
In the tooling zone, click
（ Create Step）, or in the
main menus select
Step>Create.
In the ‘Create Step’
window, define the step name
as ‘apply load’，select
‘Static, general’, click
Continue。In the pop-up
‘Edit Step’window, set
‘Nlgeom’ as ‘off’, click
OK
Lecture 5: 2D Truss Structures
8 Define Loads
In ‘Module ‘ select ‘Load’
click
（ Create Load），in the ‘Create Load’ window，
select ‘Concentrated force’, click ‘Continue’。Select the
points for applying the loads，click ‘done’, then the ‘Edit
Load’window pops up，input CF1 as 5000，CF2 as 0，click OK
Lecture 5: 2D Truss Structures
9 Define Boundary Conditions
Click
（Create Boundary Continue），
In the ‘Creat Boundary Condition’，Select Displacement, click
OK。
Select the bottom left point，click ‘done’, then in the ‘Edit
Boundary condition’, set U1, U2, U3 be zero, click OK。Repeat
the procedure for the right corner point, but only U2 is set to be
zero.
Lecture 5: 2D Truss Structures
10 Meshing
In the ‘Module’, select Mesh，select ‘Part’ for ‘object’
Click
（Seed Edges），
select the whole model，the
‘Local seeds’window pops up.
Select ‘By Number’for
‘Method’，Set ‘Number of
Elements’ to 1，click Ok。
Lecture 5: 2D Truss Structures
Click
（Assign
Element Type），select the
whole model，click ‘done’,
the ‘Element Type’window
pops up, select ‘truss’for
‘family’, choose T2D2 for
element type。
Click
（Mesh Part）
，click ‘ok’ to mesh the
frame.
Lecture 5: 2D Truss Structures
11 Submit Job
In ‘Module’ select ‘Job’
Click
（Job Manager），in the ‘Job Manager’ window
，click Create。Click Continue，the ‘Edit Job’ window pops up，
keep all parameters to their default value, click Ok。
Lecture 5: 2D Truss Structures
In Job Manager click Submit。You can see that the status changes
from ‘Submitted’ to ‘ Running’ and finally to ‘ Completed’.
The job is now finished.
Click Results，ABAQUS automatically transfer to Visualization
mode for postprocessing。
Lecture 5: 2D Truss Structures
12 Post-processing
Click
(Plot Undeformed
Shape）
Click
（Plot Deformed
Shape）
Click
（Allow Multiple
Plot States），then click
and
, the deformed and
undeformed shapes can be presented in
the same figure.
Click
(Plot Contours）to
plot contour figures.
Lecture 5: 2D Truss Structures
12 Post-processing
To save the figure shown on the screen, select file>print in the
main menu. In the ‘Print’window，select file for destination，
key in the file and fold name in File name，select Format , for
example PNG，click ok.
Lecture 5: 2D Truss Structures
Select
（Animate：Scale Factor），to show animation for
deformation
Click Tools>Query，select Probe values，click OK。set Probe to
be Nodes，select S,Mises，move mouse to a node, its Mises stress
will be displayed.
Lecture 5: 2D Truss Structures
In Probe Values select Field Output ， the Field Output window
pops up，select the variable to be displayed , for example
U，
click Ok。The contour for U1 is displayed. Put the mouse on a
node, , its values will be displayed. 。
Lecture 5: 2D Truss Structures
Click Report>Field output in the main menu，select the variable
to be output , for example S11，in setup change the output name，
for example S11.rpt ，click OK。open S11.rpt to get the results
Assignment 2: 2D Truss Structure
Problem Description:
1. Determine the nodal deflections, reaction forces, and stress for the truss
system shown below
2. E = 200GPa, A = 3250mm2 for truss member 1-4, 6, 8-11. E=120GPa,
A=1230 mm2 for truss member 5, 7
3. Take out the forces at points 1 and 7, run the analysis again and compare
the results with the previous case. What are the differences and why?
Important:
Convert all dimensions and forces into SI units.
List the results of the analysis.
Plot the deformed shape. Deadline for submission 2014-3-20