Structural Assessment of Truss and Concrete Structures

This document discusses the process of performing deformation and strength assessment of truss and concrete structures using finite element analysis in Abaqus. It covers the assumptions, FE approach, geometry, material properties, FE model, steps, loading and boundary conditions, and the results obtained from the analysis.

ENGIN5302 Modelling & Simulation EXERCISE 01 Project 2019/05
Objective
To perform the structural assessment of two different structures as two separate tasks as below:
1) Task-I : Deformation and Strength assessment of Truss Structure
2) Task-II : Deformation and Strength assessment of Concrete Structure
Problem Statement
Task-I Truss Structure
The truss shown in Figure 1 is subjected to distributed load along the top left face and point loads at various
intervals. Have performed a finite element analysis of the truss using Abaqus CAE 6.14
Figure 1: Problem Statement
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ENGIN5302 Modelling & Simulation EXERCISE 01 Project 2019/05
Assumptions and FE Approach
 All the members have a square cross section with sides b = 300 mm. See Figure-2
 The Young's modulus of the material used in the construction of the truss is E = 210 GPa. See
Figure-3 for Material Property configuration in Abaqus.

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Figure 2: Section Profile
Figure 3: Elastic Property of Steel

ENGIN5302 Modelling & Simulation EXERCISE 01 Project 2019/05
Geometry
 As mentioned in the problem statement the same geometry is created in Abaqus CAE. Firstly
the keypoints are plotted through coordinates and connected with lines in the sketch as shown
in Figure-4. The wire Model is assigned the section profile as discussed earlier.
Figure 4: Sketch
Material
As mentioned in the problem statement, structural steel Material is used. The Material Properties are as below:
Density (kg/m3) 7850
Young's Modulus (GPa) 210
Poisson's Ratio 0.3
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ENGIN5302 Modelling & Simulation EXERCISE 01 Project 2019/05
FE Model
As recommended in problem statement beam element with cubic formulation is used in Abaqus. Figure-5 gives
the details of the same.
For convergence
study we are beginning with two elements across the member and then increasing to 4, 8 and 16 elements
across the members.
Figure 6: Finite Element (FE) Model
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Figure 5: Element Type

ENGIN5302 Modelling & Simulation EXERCISE 01 Project 2019/05
Steps, Loading and Boundary Conditions
Firstly, we have created a load Step (Step-1) in Abaqus defining the analysis is of Static Structural linear analysis.
Figure-7 gives the details of the same.
Figure 7: Load Step in Abaqus
As per the problem statement we have applied 10kN force in –Y direction at three positions. Figure 8 gives the
details about the same.
Figure 8: Point load of 10kN
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ENGIN5302 Modelling & Simulation EXERCISE 01 Project 2019/05
From the slope of the truss, the distributed load is calculated for Horizontal and vertical components and applied
in Abaqus as line load for distributed load w. Figure 9 gives details of the distributed load w. The load is divided
per node, hence the annotations in the image are according to nodes (2 elements across the members). Hence
to correctly capture the distributed load we can say the more elements across the members are recommended.
Figure 9: Distributed load w
Figure 10: Boundary Condition: Roller Support
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ENGIN5302 Modelling & Simulation EXERCISE 01 Project 2019/05
Figure 11: Boundary Condition: Fixed Support
Results
Here the deformed shape of the truss is found after the analysis of the entire job and the deformed shape is
shown below.
Deformed shape:
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ENGIN5302 Modelling & Simulation EXERCISE 01 Project 2019/05
The stress contour of the truss is obtained under the results section by clicking the ‘plot contour on deformed
shape’ option.
Stress contour of truss:
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ENGIN5302 Modelling & Simulation EXERCISE 01 Project 2019/05
From the above stress contour plot it is evident that the stress is maximum at the red zone and specifically at the
extreme red point where the stress is 2.707*10^6 N.
Maximum stress point:
The red dot point is indicated as maximum stress point in the above figure.
Now, the maximum deflection occurred at the extreme green point as evident from the stress contour plot.
Maximum deflection point:
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ENGIN5302 Modelling & Simulation EXERCISE 01 Project 2019/05
In the above figure the maximum deflection point is shown as red dot.
Summary and Conclusion
Thus as summary the finite element analysis of the given truss structure is performed in Abaqus and the
structure of beams and its final deformation after applying finite element analysis for a step time of 1 second is
shown in the above sections. The maximum deformation is found in just right adjacent node of A where 10 kN
force is applied and the maximum deflection point is found at just left adjacent node of A. Furthermore
convergence study is done with 2, 4, 8 and 16 elements per beam or member and the procedure is shown in the
above sections. The cross section of beam for convergence study is considered uniform for all beams and the
beams are considered to be independently deformed from each other with respect to force applied. The Young’s
modulus of the truss is considered uniform of 210 Giga Pascal and entered in the steel material section as shown
in the above sections.
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