Parametric Study of Steel Beam with Web Opening Using ANSYS · find way to decrease the cost of...

Parametric Study of Steel Beam with Web Opening Using ANSYS

Jinsy Ratheesh M.Tech student, department of Civil Engineering

Vimal Jyothi Engineering College Kannur, Kerala, India

Dona Chacko Assistant Professor, department of Civil Engineering

Vimal Jyothi Engineering College Kannur, Kerala, India

Abstract—Several factors can impose height

limitations in multi-story buildings, such as zoning

regulations, economic requirements and aesthetic

considerations. To minimize floor height, a common

solution is to cut openings into steel beam webs in order

to pass utilities through it. The use of steel beams with

web openings (SBWOs) for structures such as industrial

buildings and high-rise buildings has turned out to be

extensive in recent times. There are numerous motives

for which openings are kept. In this respect, a

parametric study was conducted on different models on

SBWOs. The initiative was to identify the maximum load

behaviour, and Additional deflection due to single and

multiple openings. Also consider the stress concentration

in the web openings.. The examples involve simply

supported beams either with no web openings, square

web openings or circular web openings. All the beams

were analysed by the finite element method by using

general finite element analysis software ANSYS

Workbench. Keywords—steel beams with web openings (SBWOs), finite

element analysis

I. INTRODUCTION Steel beam with web opening (SBWOs) are

combine beauty versatility, economy in steel design. These are fabricated from standard rolled section & are engineered to save time of construction. Many attempts have been made by Structural Engineers to find way to decrease the cost of steel structures. Due to limitation on maximum allowable deflection the high strength properties of structural steel cannot always be utilized to best advantages. As a result several new methods have been aimed at increasing the stiffness of steel members without any increasing in weight of the steel required. Beam with web opening were one of these one solution. The shape of the web opening will depend upon the designer’s choice & the purpose of the openings. Steel beam with web opening is a type of structural steel beam having opening in its web to allocate space for passage for large pipes, hydraulic and ventilation pipes, electric cables and air conditioning ducts within the web of structural steel beam it is considered to be very effective in increasing floor height in high-rise building and industrial building where floor height is very critical requirement.

The scope of study deals with, Deformation characteristics, equivalent (von misses) stress, shear stress on beam. The introduction of an opening in the web of the beam alters the stress distribution within the member and also influences its collapse behavior. Thus, the efficient design of beams and plate girder sections with web openings has become one of the important considerations in modern structures.

A. Objectives

To conduct analytical investigation of steel beam with web openings.

To study the different parameters with different number of openings in the web of the steel.

To compare the safe conditions of stresses in beam with circular web openings and square web openings

II. STUDY ON STEEL BEAM WITH WEB OPENING The study considers the shear stress,

equivalent (von misses) stress, deformation of steel beams with doubly symmetric I-section. The examples involve fixed supported beams either with circular openings or square openings. The centroids of the openings lie along the centerlines of the beams. The values of Young’s modulus of elasticity E and Poisson’s ratio μ are taken 2.1×105 N/mm2 and 0.3 respectively. The sectional properties of the I-section ISMB 400 are as shown in Fig 1. The specimens of fixed beam of ISMB 400 are of length L = 10000 mm, web thickness tw = 8.9 mm, the overall web depth d = 368 mm, flange thickness tf = 16 mm, and flange width bf = 140 mm.

Number of openings numbered from the support to the next support. The size of openings is .5h. Where h indicates height of web of steel beam. Numbers of openings are 1, 3, 5, 7, 9 and position of centroids of the openings lie along the centerlines of the beams.

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International Journal of Applied Engineering Research ISSN 0973-4562 Volume 14, Number 12, 2019 (Special Issue) © Research India Publications. http://www.ripublication.com

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Fig.1 Sectional properties of ISMB 400

ΙΙΙ. MODELLING AND ANALYSIS

A. Finite Element Method (ANSYS) – Analysis

The finite element method is a numerical analysis technique for obtaining approximate solutions to a wide variety of engineering problems. Although originally developed to study stresses in complex airframe structures, it has since been extended and applied to the broad field of continuum mechanics. Because of its diversity and flexibility as an analysis tool, it is receiving much attention in engineering schools and in industry. The resourcefulness of the analyst usually comes to the rescue and provides several alternatives to overcome this dilemma. One possibility is to make simplifying assumptions to ignore the difficulties and reduce the problem to one that can be handled. Sometimes this procedures works; but, more often than not, it leads to serious inaccuracies or wrong answers. Now that computers are widely available, a more viable alternative is to retain the complexities of the problem and find an approximate numerical solution.

B. Steps Followed While Analysis Of Beam

A finite element model of a fixed supported ISMB 400 of actual span length 10 m and a pressure of .2MPa acting on the beam is analyzed. Fig 2 shows the steps followed by ANSYS.

1. Engineering data: In this step material properties of steel are provided

Fig. 2 Static structure

2. Geometry: Geometry of I-section is created

using rectangular tool in sketching options. The unwanted portions are removed using trim. Using the extrude option change the geometry in to 3D.

Fig.3 ANSYS model for solid beam

3. Model: Assigning the properties of the

section is done in this step. For getting the accurate value of result meshing of the solid beam is carried out. It is shown in Fig.4. By selecting the faces for supports the support conditions are assigning. Also forces acting on the beam are provided in this step as shown in Fig.5.

Fig.4 Meshing ISMB 400


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Fig. 5 Meshing ISMB 400

4. Solution: Solution of the beam is solved in

this step. Finally the shear stress, equivalent (von-mises) stress and deformation are added to the solution and evaluate all the results

C. Input parameters

Young’s modulus of elasticity E = 2.1×105

N/mm2

Poisson’s ratio μ = 0.3

ΙV. RESULTS AND DISCUSSION The shear stress, equivalent (von mises) stress and deformation of ISMB 400 without opening, with circular web opening and square web opening are evaluated. The results obtained through finite element analysis using ANSYS workbench are tabulated below. Table 1 is the results of circular openings and Table 2 is the results of square openings.

Table 1 Analysis results of circular web openings

No. of

openings

Deformation

(mm)

Shear

stress

(mpa)

Equivalent(von

mises) stress

(mpa)

0 19.254 4.4991 224

1 19.23 9.5135 238.84

3 19.352 12.56 238.53

5 19.407 11.014 239.4

7 19.478 10.141 239.44

9 19.547 9.3014 236.06

Table 2 Analysis results of square web openings

No. of

openings

Deformation

(mm)

Shear

stress

(mpa)

Equivalent(von

mises) stress

(mpa)

0 19.254 4.4991 224

1 19.215 10.098 241.28

3 19.458 27.581 240.75

5 19.526 27.761 241.3

7 19.639 25.734 240.42

9 19.781 27.297 240.31

The Fig. 6 to Fig.8 shows the total deformation, Equivalent (Von-Mises) stress, Shear stress of steel beam with different numbers of circular web openings. A .2 Mpa load is applied on the beam.

Fig. 6 Total deformation of SBWO-1 circular opening

Fig. 7 Equivalent (Von-Mises) stress of SBWO-5 circular openings


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Fig. 8 Shear stress of SBWO-9 circular openings

The Fig. 9 to Fig.11 shows the total deformation, Equivalent (Von-Mises) stress, Shear stress of steel beam with different numbers of square web openings.

Fig. 9 Total deformation of SBWO-3 square openings

Fig. 10 Equivalent (Von-Mises) stress of SBWO-7 square openings

Fig. 11 Shear stress of SBWO-5 square openings

The Fig. 12 shows the graphical representation of the deformation of steel beams with square and circular web openings.

Fig. 12 Deformation of circular and square web openings

The Fig. 13 shows the graphical representation of Equivalent (Von-Mises) stress of steel beam with different numbers of square and circular web openings. Von misses stress is used in ANSYS in order to find the failure criteria of beam at applied load as steel is used as material in analysis and yield stress of steel is 250 N/mm2 shown in green colour in Fig.13 so Von mises stress greater than yield stress of material at given load is considered as failure of beam.


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Fig. 13 Equivalent (Von-Mises) stress of circular and square web

openings

The Fig. 14 is the graphical representation of shear stress of steel beam with different numbers of square and circular web openings. Shear stress limit for ISMB 400 is .4fy.

Fig 6.1.36: Shear stress of circular and square web openings

A. Discussion

By comparing the ISMB 400 steel beam with circular and square web openings with its reference beam the deformation is less for SBWOs. From the Fig 6.1.1 when a .2Mpa pressure is applied on the beam without openings the deformation is 19.254mm. The minimum deformation is for steel beam with one circular opening (19.215mm). It is less than a normal steel beam. The maximum value of deformation is 19.781mm for web with nine square openings. By the help of designing and analysis of 11 models of beams comparing the square web opening and circular web opening square shape has more deformation. When the numbers of openings are increased the total deformation of the steel beam is

also increased. The deformation of beam depends on the number of openings. In normal beam without web opening the Equivalent stress value is 224MPa. By observing the Figures of shear stresses there is only slight variations in stresses of square and circular openings. In the case of circular openings maximum value of stress 239.44 MPa is for 7 numbers of openings. And in the case of square web openings maximum stress 241.3 MPa is for 5 numbers of openings. When the numbers of openings are increased by 0, 1, 3, 5, 7, 9 Von misses stress also varies in SBWOs. From the graphs and analysed results we can say that Von misses stress will change with number of openings but it also depends on the positions of openings provided. So we can’t say that a gradual degrease or gradual increase in the stress value when number of openings is increased. Here the stress values of all the models are less than the yield stress 250Mpa. So we can say that all models are safe for constructions. By studying the comparing graphical representation of shear stress of steel beam with different numbers of square and circular openings square openings has more stress value. The shear stress value of normal beam is obtained as 4.4991MPa. Minimum shear stress for circular opening is 9.3014MPa with 9 opening and maximum is for 3 openings 12.56MPa. In the case of square minimum and maximum shear is 10.098MPa with one opening and 27.761MPa for 5 openings respectively. There is no gradual decrease or gradual increase in shear stress value when number of openings is increased.

Based on IS 800 Average shear stress of I beam should not exceed .4fy for unstiffened web. Here .4fy equal to 100MPa. In this analysis of SBWOs the shear stress value is comparatively very less than 100MPa

V. CONCLUSION For the analysis 10m span of steel beam (ISMB400) is considered and analytical investigations are conducted. Then studied the different parameters like Von-Misses stress, Shear stress and Total deformation of square and circular opening in web circular and square using ANSYS software. From the results it is observed that,

1. When number of openings in web is increases total deformation of the beam is also increases but it is a small change and it does not affect the constructions.

2. The parameters studied Von-Misses stress, Shear stress and Total deformation are depends on the number of openings but it also depends on other factors like size spacing position of openings etc. So there is no gradual degrease or increase in values of shear stress and equivalent stress. The steel beams with web openings are in safe condition.

3. Circular web openings were found to be very effective in all respects, like it shows a very


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less deformation shear stress and equivalent stress when comparing with square web openings.

4. Circular openings are easy to fabricate and it has architectural appearance.

5. The parameters studied in this analysis are in safe condition for a construction.

REFERENCES [1] Ankit K. Mata, Bhavin S. Bhagat and Nakul D. Gami (2018), “ parametric study of steel beam with web opening of different shape, size and position using finite element method”, International

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Engineering Structures, Vol. 50, pp. 197–206.

[3] Chung, K.F., Liu, T.C.H. and Ko, A.C.H. (2001), “Investigation of Vierendeel Mechanism in Steel Beams with Circular Web Openings”, Journal of Constructional Steel Research, Vol. 57, pp.

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[4] Konstantinos Daniel Tsavdaridis,Cedric D’Mello (2016), “Vierendeel bending study of perforated steel beams with various novel web opening shapes through nonlinear finite element analysis”, journal of structural engineering ASCE, pp.1214-1230.

[5] M. Y. Shan, R. A. LaBoube, and W. W. Yu (2015), “Bending and shear behavior of web elements with openings”, ASCE journal

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[6] N.C. Hagen, P.K.Larsen, A.Aalberg (2009) “Shear capacity of steel plate girders with large web Openings”, Part I: Modeling and simulations, Journal of Constructional Steel Research pp.142-150 [7] Prof. R. R. Jichkar, Prof. N. S. Arukia, Prof. P. D. Pachpor (2014), “Analysis of Steel Beam with Web Openings Subjected To Buckling Load” Int. Journal of Engineering Research and

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[8] Samadhan G. Morkhade and Laxmikant M. Gupta (2015), “Analysis of steel I-beams with rectangular web openings: experimental and finite element investigation”, Engineering

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[9] Samadhan G. Morkhade and Laxmikant M. Gupta (2015), “An experimental and parametric study on steel beams with web Openings”, Int J Adv Struct Eng (2015) 7:249–260

[10] IS 800:2007 [11] Steel tables


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