Fatigue Life Prediction of Austenitic Type 316L Stainless Steel Using ABAQUS

Khairul Azhar Mohammad1, a, Mohd Sapuan Salit2, b, Edi Syams Zainudin1, 3, c, Nur Ismarubie Zahari1, d and Aidy Ali4, e

1Department of Mechanical and Manufacturing Engineering, Universiti Putra Malaysia, 43400 UPM, Serdang Selangor, Malaysia

2Institute of Tropical Forestry and Forest Products (INTROP), Putra Infoport, Universiti Putera Malaysia 43400 UPM Serdang Selangor

3School of Engineering & Design, Brunel University, Uxbridge Middlesex, UB8 3PH United Kingdom

4Department of Mechanical Engineering, National Defence University of Malaysia, Sungai Besi Camp, 57000 Kuala Lumpur, Malaysia

ak.amohd@yahoo.com, bedisyam@eng.upm.edu.my, csapuan@eng.upm.edu.my,

drubie@eng.upm.edu.my, eaidyali@upnm.edu.my

Keywords: Fatigue Life; 316L Stainless Steel; Yield Strength; Fatigue Limit.

Abstract. This work has carried out on Type 316L stainless steel of hollow bar specimen. The aim

of this work is to determine the fatigue life prediction using Finite Element Analysis (FEA). The

simulation performed by applied the different stress level to predict the stress of operation to

measured life at the measured of operation stress. The simulation emphasis is focused upon the

importance of characterize the fatigue limit with compared to data experimental. Comparison of

fatigue limit between both simulation and experiment is 150 MPa and 161 MPa, respectively which

will provide good agreement in terms of accuracy prediction even various aspects should be taken

into account in simulation.

Introduction

In a leading-edge of global market nowadays, fatigue mechanism that experienced by engineering

components in daily life is one of the crucial problems and challenges in engineering field. Failure

in the structure can be induced by fatigue. The demand for higher operational capabilities and

efficiencies has lead to higher service temperatures as a way of life [1]. Thus, costly and time

consuming fatigue tests are often carried out to ensure safety of the design model. Examples of

structures such as pipelines, aerospace sector, industrial gas turbines, and pressure vessels and so on

which require such information to predict the durability [1]. Therefore, fatigue analysis has always

been a crucial and vital method for product development processes as all the allegation and

behavior of repeated loads, fluctuating loads and others will be stated clearly [2].

There are advantages of performing a simulation analysis instead of actually fabricate and testing

the design. Time saving and cost effective will be the most significant advantages of simulation as it

allows us to study the behavior of a system without fabricate the real model. Furthermore, it is a

time consuming and expensive project to design, build and test. Moreover, the experiment for

fatigue life of stainless steel 316L model is a destructive testing which requires destroying the

model after performing the experiment. Besides, more models are needed to be fabricated to

perform multiple experiments so as to get more accurate results. Simulations take the building and

rebuilding phase out of the loop by using the model already created in the design phase [3].

The simulation analysis is most carried out in any investigation and research with compared to

performing the multiple testing due to it is cheaper and faster to get the data result. The level of

detail from a simulation is another advantage of a fatigue life simulation analysis. According to

Nicholas et al.[3], simulation can provide results that not are not experimentally measurable with

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the current level of technology. Furthermore, the finite element method is a way of getting a

numerical solution to a specific problem as simulation can provide more accurate prediction results

compare to analytical model when problems is too small to measure, the probe is too big and is

skewing the results[4]. Furthermore, any instrument failure will cause the experimental results to

deviate from actual result. Besides, the simulation analysis can be set to run for as many time steps

and at any level of detail desired [2]. This paper was carried out to show the comparison on fatigue

life of simulation and experimental results on stainless steel at room temperature.

Methodology

Fatigue Simulation The fatigue simulation explained the analysis methodology that has been used

in the simulation to predict fatigue life of stainless steel. The simulation model is imported from

CATIA V5 file to undergo analysis as shown in Fig. 1. The part is created and the material

properties are inserted. A section is required to be created and a region is assigned as the section

created so that it possesses all the defined material properties. The assembly is created as ABAQUS

works by analyzing assemblies, which are collections of parts. A step needs to be created and the

procedure is set as dynamic implicit. The boundary condition is used to fix the either one’s end to

move in any direction. Then the load is created with defining the magnitude of load, load amplitude

and the load distribution is inserted. The Fig. 2 shows that the next part is carried out to mesh the

whole model with the appropriate global seeds. The global seeds are important so as to improve the

result accuracy. Lastly, the job is created and submitted for full analysis. Visualization results will

be shown when analysis is completed.

Figure 1: Computer Aided Design (CAD) design and its dimension in mm.

Figure 2: Meshed model.

Results and Discussion

Type 316L stainless steel is a ductile material in which it is able to yield strength under a

continuous load at normal temperature as shown in Fig. 3. In the simulation, the stress-strain data

was taken from node 1202 in the specimen which is a region of stress concentration. Abaqus

extracted the data of the strain against time and stress against time where to compare with

experimental data. Data of simulation and experimental analysis for yield strength are 70.2 MPa and

75.3 MPa which has a slightly difference around 5.1 MPa. According to Velay et al., there are

several aspects to explain the difference between the simulation and experimental results of a failure

460 Key Engineering Materials - Development and Application

to consider the distribution of bulk temperature in simulations where the temperature it increases the

creep in the specimen, incomplete formulation of the model simulations and the experimental error

in the measurement of pressure [5]. Figure 4 shows the result of final visualization under applied

fatigue test obtains from Abaqus.

Figure 3: Stress vs Strain.

Figure 4: Visualization result after analysis finished.

Figure 5: Comparison of fatigue life on stainless steel.

The stress life (S-N) plotted is shown in Fig. 5. With considering seven’s value of mean and

amplitude stresses which range of 160 MPa till 334 MPa used for applied in numerical analysis in

tension-tension fatigue mode by in order to get life time at variable amplitude loading. It is evident

that the fatigue limit of experimental data is higher than simulation results. The predicted result

from simulation was compared with the experimental data that was obtained in same parameters

and same dimension. The experimental data agreed well with simulation data. It was not possible to

compare the result at the same test condition due to the lack of experimental data because of limited

supply of test materials test machine as well as time consuming. Beden et al. reported that the

fatigue limit of the experimental results is slightly higher than simulation predicted that there can be

caused by micro-structural’s homogeneity in the material properties, surface differences, test

0

50

100

150

200

250

300

350

400

1.E+03 1.E+04 1.E+05 1.E+06 1.E+07 1.E+08

Ma

xim

um

Str

ess,σ

(MP

a)

Number of cycle to Failure, Nf

experimental

simulation

Advanced Materials Research Vol. 911 461

environment, and other factors [6]. Moreover, the big difference for fatigue limit is observed due to

the specimens have different grain size and shape of the specimen itself in terms of machining to

the cylinder or plate form [7,8].

Acknowledgement

This research was funded by the Higher Learning Ministry for financial support under the

ScienceFund MOSTI project (Project No.: 03-01-04-SF1788).

Conclusions

Type 316L stainless steel has been successfully carried out using the finite element analysis. With

comparing the simulation results are good trend similar with the experimental data with some aspect

did not take into account of simulation. The fatigue life in simulation is determined and validated by

experimental data. This indicates that the maximum stress in the simulation of stainless steel 316L

is slightly lower than experimental data. Therefore, comparison between simulation and

experimental results is shown a well agreement as both of results were plotted and compared in this

research.

References

[1] N.K. Sinha and P.Vasudevan: J. Nucl. Mater. Vol. 119 (1983), p. 240

[2] A. O. I. Mohd, in: Fatigue Life for Submarine Pipeline using Finite Element Analysis (FEA),

Thesis of Master of Manufacturing System Engineering, (2012), Universiti Putra Malaysia.

[3] T. J. R. Nicholas and J. R. Zuiker: Int. J. Fract Vol. 80(1996), p. 219

[4] K. U. Snowden, D. S Hughes,and P. A Stathers: Int. J. Fatigue Vol. 4 (1982), p. 217

[5] V. Velay, G. Bernhart and L. Penazzi: Int. J. Fatigue Vol. 38 (2009), p. 793

[6] S.M. Beden, S. Abdullah and A.K. Ariffin: Eur. J. Sci. Res. Vol. 38 (2009), p. 364

[7] D.W. Kim, J.H. Chang and W.S. Ryu: Int. J. Press. Vess. Pip. Vol. 85(6) (2008), p. 378

[8] W.Y. Maeng and Y.H. Kang: Creep-Fatigue and Fatigue Crack Growth Properties of 316LN

Stainless Steel at High Temperature, in Transactions of the 15th

International Conference on

Structural Mechanics in Reactor Technology (SMiRT-15), August 15-20, 1999, Seoul, Korea.

462 Key Engineering Materials - Development and Application

Key Engineering Materials - Development and Application 10.4028/www.scientific.net/AMR.911 Fatigue Life Prediction of Austenitic Type 316L Stainless Steel Using ABAQUS 10.4028/www.scientific.net/AMR.911.459

DOI References

[1] N.K. Sinha and P. Vasudevan: J. Nucl. Mater. Vol. 119 (1983), p.240.

http://dx.doi.org/10.1016/0022-3115(83)90200-3 [3] T. J. R. Nicholas and J. R. Zuiker: Int. J. Fract Vol. 80(1996), p.219.

http://dx.doi.org/10.1007/BF00012670 [4] K. U. Snowden, D. S Hughes, and P. A Stathers: Int. J. Fatigue Vol. 4 (1982), p.217.

http://dx.doi.org/10.1016/0142-1123(82)90004-4 [7] D.W. Kim, J.H. Chang and W.S. Ryu: Int. J. Press. Vess. Pip. Vol. 85(6) (2008), p.378.

http://dx.doi.org/10.1016/j.ijpvp.2007.11.013