Introduction (791 words) CTOD (Crack Tip opening displacement) test can be defined as the measure of the resistance towards the propagation of the crack when a specimen is subjected to plastic loading. As the technology is growing day by day, the safety in the oil and gas industries is becoming essential and due to which the study of CTOD test plays a prominent role in considering the safety and the strength of the on shore, offshore and underwater pipelines through which oil and gas are carried to different places of the world. Ongoing technology involves the usage of C-Mn steel pipelines combined with an internal corrosion resistance alloy (CRA) layer. This is either bonded metallurgically to the clad pipe or arranged in place with the lined pipe(de Souza, Ruggieri et al. 2016).Currently, Engineering critical assessment (ECA) procedures such as API579 (American Petroleum Institute, 2007) and BS7910 (British Institution, 2013) are being used for the assessment of the specimens which are under low levels of plasticity and these are made up of homogenous materials. However these processes do not produce accurate results when large scale yielding conditions are applied with different type of welded joints. The single edge notched tension (SENT) specimen is used frequently In the case of the circumferential surface flaws in pipes and this is because it has a geometry constraint in front of the crack tip which is similar to the cracks in pipes(Xu, Zhuo et al. 2016). Upon the synthesis of the research, it was found out that Fatigue Crack Growth Rate (da/dN), heat treatment process, austempering, tempering, hardening, rolling etc are some of the factors which can be considered in the process of CTOD in order to determine the rate of cracking when a crack is developed initially under specific conditions and much recent research has focused on the development of standardized procedures for crack growth resistance testing using SE(T) fracture specimens(Sarzosa, Barbosa et al. 2017). Other important factors include EBSD, Fatigue Threshold and heat affected zones. The above themes were considered in order to determine the outcome of the CTOD test for different specimens including steels, nickel, aluminium under different loading conditions and various welded joints. There is an involvement of many factors and estimation methods along with correction factors for the investigation of J integral and the variations are recorded in picture or graphically. Other important analysis included analysis of micro structure of the composition of the steels in order to estimate the hardness of the material and its ability to withstand fatigue. Evaluation of fracture toughness for two nickel containing steels as an alternative in Carbon dioxide transporting pipelines for Enhanced Oil Recovery, Influence of crack parameters, nonlinear elastic-plastic fracture responses of a flawed pipeline and comparison with the BS7910:2013 code(Ariffin, Zhang et al. 2017), Investigation of crack growth behaviour for fatigue in a rolled AZ31 magnesium plate and modelling, determination of relationship between da/dN and plastic CTOD for the AA6082-T6 aluminum alloy, independent of stress ratio, showing that the plastic CTOD is an interesting alternative to DK in the analysis of fatigue crack propagation(Antunes, Rodrigues et al. 2016), finding out the permissible value and analysis of CTOD test(Yu and Sa 2013), evaluating the effect of hardening and tempering vs austempering on mechanical parameters such as J integral and CTOD(Pustaić and Cajner 2014), investigation of the reason behind the mismatch effects of strength on fracture and discussion of variation between CTOD and charpy impact tests, Investigation of characterization with the help of small punch(Martínez-Pañeda, García et al. 2016), Determination of strain based estimation formulae for CTOD and comparison for different crack sizes between BS7910 and finite element analysis(Ariffin, Zhang et al. 2017), analysing of composition of precipitates and fracture mechanism with the help of scanning electron microscope, energy dispersive spectroscopy and optical microscope(Chen, Lu et al. 2015) were among the important research questions which were analysed in the research. Most of the above mentioned research areas support each other however there are cases where the results found out contradict each other where correction factors and standard conditions and dimensions of specimens are not applied. However all the current work was performed under fixed temperatures and standard working conditions due to which there might be inaccuracy of the results derived in the real world practice. This research question can be answered by using the research preformed by (Pustaić and Cajner 2014) regarding the J integral and its relativeness to the CTOD test high strength steels and hence this can be used as the primary source of research in order to answer the research question stipulated above. Consideration of mechanical parameters and correction needs to be used and the experimental analysis is to be performed using different tests such as charpy test in order to get accurate results. REFERENCES: Antunes, F. V., et al. (2016). "A numerical analysis of CTOD in constant amplitude fatigue crack growth." Theoretical and Applied Fracture Mechanics 85, Part A: 45-55. Ariffin, M. Z., et al. (2017). "Elastic-plastic fracture response of multiple 3-D interacting cracks in offshore pipelines subjected to large plastic strains." Engineering Failure Analysis. Minami, F. (2012). Equivalent CTOD concept for correction of CTOD toughness for constraint loss in steel weld components. Materials Science Forum. 706-709: 97-104. Pustaić, D. and F. Cajner (2014). Influence of heat treatment on crack tip opening displacement and on resistance of crack propagation of alloyed steel. Key Engineering Materials. 592-593: 660-663. Sarzosa, D. F. B., et al. (2017). "Fracture resistance testing of dissimilar nickel–chromium girth welds for clad line pipes." International Journal of Fracture 205(2): 169-188. de Souza, R. F., et al. (2016). "CTOD estimation procedure for clad pipe girth welds subjected to bending load." Procedia Structural Integrity 2: 2068-2075. Xu, J., et al. (2016). Constraint effect on the ductile fracture behavior of high-strength pipeline steels. Materials Science Forum. 850: 899-904. Yu, Q. M. and H. L. Sa (2013). The study of CTOD test and allowable value. Advanced Materials Research. 739: 275-277. Martínez-Pañeda, E., et al. (2016). "Fracture toughness characterization through notched small punch test specimens." Materials Science and Engineering A 657: 422-430. Chen, X., et al. (2015). "A comparison between fracture toughness at different locations of longitudinal submerged arc welded and spiral submerged arc welded joints of API X80 pipeline steels." Engineering Fracture Mechanics 148: 110-121. Literature Planner Student Name: Merajuddin Mohammed Student Number: 5483712 Topic: CTOD (crack tip opening displacement) test of high strength steels. Reference Number: 1 Authors: Y. M. ZHANG et. al. Title of Article: Engineering critical assessment for offshore pipelines with 3-d elliptical embedded cracks. Type: Conference paper Publication: Elsevier BV Year Published: 2015 Number of citations: 1364 (Scopus) Primary or Secondary: Primary Publication Rating: CiteScore:1.84 Rank: 38 Percentile: 85th In-Category: Engineering CiteScore Year: 2015 What themes were discussed in the Literature Review? Elliptical embedded crack, CTOD, pipeline girth weld, large plastic strain. What was the research question? Determination of strain based estimation formulae for CTOD and comparison for different crack sizes between BS7910 and finite element analysis. Design: Graphical representation by numerical and experimental analysis What was the finding? Analysis of pipeline girth weld along with an elliptical embedded crack under large plastic bending with thr help of 3-d elastic plastic finite element models. What were the gaps? The experimental analysis was performed only under two loading conditions with an elliptical embedded crack which was subjected to large plastic bending. Reference Number: 2 Authors: XU CHEN et. al. Title of Article: A comparison between fracture toughness at different locations of longitudinal submerged arc welded and spiral submerged arc welded joints of API X80 pipeline steels. Type: conference paper Publication: Elsevier BV Year Published: 2015 Number of citations: 1922 (Scopus) Primary or Secondary: primary Publication Rating: CiteScore: 2.44 Rank: 62 Percentile: 87th In-Category: Mechanical engineering CiteScore Year: 2015 What themes were discussed in the Literature Review? X80 pipeline steel, single edge notched bending specimen precipitate, welded joints. What was the research question? Analysing of composition of precipitates and fracture mechanism with the help of scanning electron microscope, energy dispersive spectroscopy and optical microscope. Design: Pictorial and graphical representation and experimental analysis. What was the finding? Comparison of critical fracture toughness between different locations of SSAW and LSAW joints and fractography of specimens was determined with the help of SEM and EDS. What were the gaps? The analysis was limited to specimens subjected to only longitudinal submerged arc welding (LSAW) and spiral submerged arc welding (SSAW) and no other welding inspection was employed. Reference Number: 3 Authors: EMILIO MARTINEZ-PANEDA et. al. Title of Article: Fracture toughness characterization through notched small punch test specimens. Type: Journal. Publication: Elsevier BV Year Published: 2016 Number of citations: 1922 (Scopus) Primary or Secondary: Primary Publication Rating: CiteScore: 3.01 Rank: 33 Percentile: 93rd In-Category: Mechanical Engineering CiteScore Year: 2015 What themes were discussed in the Literature Review? Finite Elements, small punch test, CTOD, fracture toughness, damage. What was the research question? Investigation of characterization with the help of small punch test is determined. The outcome is checked with two dissimilar grade of Cr MoV steel and variations in toughness of the material is captured. Design: analysis by experiment and graphical representation. What was the finding? A combination of numerical and experimental framework in notched small punch test for the assessment of fracture toughness is determined. What were the gaps? The numerical and experimental analysis applied and was limited to only two grades of CrMoV steel. Reference Number: 4 Authors: TOMOYA KAWABATA et. al. Title of Article: Comparative study of CTOD-resistance curve test methods for SENT specimens. Type: Conference paper Publication: Elsevier BV Year Published: 2016 Number of citations: 1922 (Scopus) Primary or Secondary: Primary Publication Rating: CiteScore: 2.44 Rank: 62 Percentile: 87th In-Category: Mechanical Enginerring CiteScore Year: 2015 What themes were discussed in the Literature Review? Rotational factor, testing of toughness, crack tip opening displacement strain hardening, plastic hinge model. What was the research question? Determination of new method of CTOD calculation and verification of the method numerically and experimentally. Design: Numerical analysis. What was the finding? Implementation of new method of CTOD calculation by introducing correction factors into the plastic and elastic terms independently. What were the gaps? The proposed calculation for new CTOD formula is only valid when new factor f is used in order to correct the elastic and plastic terms. Reference Number: 5 Authors: RODOLFO F DE SOUZA et. al. Title of Article: CTOD estimation procedure for clad pipe girth welds subjected to bending load. Type: Conference paper Publication: Elsevier BV Year Published: 2016 Number of citations: 1922 (Scopus) Primary or Secondary: Primary. Publication Rating: CiteScore: 2.44 Rank: 62 Percentile: 87th In-Category: Mechanical Enginerring CiteScore Year: 2015 What themes were discussed in the Literature Review? ETA procedure, CTOD, weld strength mismatch, pipeline girth welds. What was the research question? Determination of CTOD for defects in order to find out the application of the equivalent stress strain relationship approach. Design: Analysis by estimation scheme numerical methods and material models. What was the finding? Demonstration of CTOD evolution along with bending moment is fairly forecasted with the help of new method instead of using finite element simulations. What were the gaps? Involvement of complex numerical methods and procedures and there is no experimental support to prove that the methods mentioned by the authors are more dependable. Reference Number: 6 Authors: FUMIYOSHI MINAMI Title of Article: Equivalent CTOD concept for correction of CTOD toughness for constraint loss in steel weld components. Type: Conference paper. Publication: Trans Tech publications. Year Published: 2012. Number of citations: 2106 (Scopus) Primary or Secondary: Primary Publication Rating: CiteScore: 0.29 Rank: 377 Percentile: 27th In-Category: Mechanical Enginerring CiteScore Year: 2015 What themes were discussed in the Literature Review? Failure assessment diagram, Weibull criterion for stress, CTOD fracture toughness. What was the research question? Investigation of failure assessment diagram in order to compare the results between conventional and unconventional procedure. Design: Numerical problem solving and pictorial representation. What was the finding? Numerical analysis helps in finding out precise fracture assessment of welded joints when compared to the conventional procedure. What were the gaps? Involvement of complex numerical problem solving and lack of experimental support.  Reference Number: 7 Authors: JIE XU et. al. Title of Article: Constraint effect on the ductile fracture behaviour of high strength pipeline steels. Type: Journal. Publication: Trans Tech publications. Year Published: 2016 Number of citations: 2106 (Scopus) Primary or Secondary: Primary. Publication Rating: CiteScore: 0.29 Rank: 377 Percentile: 27th In-Category: Mechanical Enginerring CiteScore Year:2015 What themes were discussed in the Literature Review? Finite element analysis, Large scale yielding, crack tip constraint. What was the research question? Determination of ductile properties of tearing with the help of axis symmetric models and 2-d plane strain for internal and external circumferential cracks of a pipe. Design: Simulation by finite element models. What was the finding? Results obtained from SENB specimens are highly unchanging when compared to SENT with respect to the pipes. What were the gaps? No variation in the dimensions of specimen and the result was completely based upon the particular methods of simulation and no physical experiment was performed. Reference Number: 8 Authors: DRAGAN PUSTAIC AND FRANJO CAJNER. Title of Article: Influence of heat treatment on CTOD and on resistance of crack propagation of alloyed steel. Type: Conference paper. Publication: Trans Tech publications. Year Published: 2014 Number of citations: 2059 (Scopus) Primary or Secondary: Primary Publication Rating: CiteScore: 0.21 Rank: 401 Percentile: 22nd In-Category: Mechanical Engineering CiteScore Year: 2015 What themes were discussed in the Literature Review? J-integral, procedures of heat treatment, parameters of fracture mechanics, austempering, hardening and tempering, CTOD. What was the research question? Evaluating the effect of hardening and tempering vs austempering on mechanical parameters such as J integral and CTOD. Design: Experimental analysis and observation. What was the finding? Specimens which are subjected to austempering and tempering reflect greater resistance towards stable crack growth. What were the gaps? The procedures adopted in the experiment were limited and no variation in the atmospheric conditions and dimensions of the component. Reference Number: 9 Authors: GIMING YU QAND HAOLIANG SA Title of Article: Study of CTOD test and allowable value. Type: Conference paper. Publication: Trans Tech publications. Year Published: 2013 Number of citations: 7285 (Scopus) Primary or Secondary: Primary Publication Rating: CiteScore: 0.08 Rank: 234 Percentile: 10th In-Category: Enginerring CiteScore Year: 2015 What themes were discussed in the Literature Review? Fracture toughness, base metal, CTOD and allowable value. What was the research question? Finding out the permissible value and analysis of CTOD test Design: Analysis by experiment. What was the finding? Determination of toughness of the fracture for the structure meets the standards. What were the gaps? Experiment was performed under controlled temperature and atmosphere and with fixed specimen sixe and shape. Reference Number: 10 Authors: Y CHIBER et. al. Title of Article: Strength-mismatch effect on steel weld ATAZ toughness in CTOD and charpy tests. Type: Journal. Publication: Institut International de la Soudure. Year Published: 2010 Number of citations: 273 (Scopus) Primary or Secondary: Primary. Publication Rating: CiteScore: 0.93 Rank: 43 Percentile:68th In-Category: Metals and alloys. CiteScore Year: 2015 What themes were discussed in the Literature Review? COD, mismatch, dynamic tests for fractures, toughness by impact, heat affected zone. What was the research question? Investigation of the reason behind the mismatch effects of strength on fracture and discussion of variation between CTOD and charpy impact tests. Design: Analysis by experiment and observation. What was the finding? More attention is required in order to apply charpy test of impact and evaluation of results for CTOD fracture toughness gaps when there is a mismatch of strength in welded joints. What were the gaps? Two methods were involved in the experiment under standard conditions and the standard dimensions of the work pieces. Reference Number: 11 Authors: FUMIYOSHI MINAMI et. al. Title of Article: Revision of ISO 27306 for CTOD Toughness Correction for Constraint Loss. Type: Conference paper. Publication: Trans Tech publications. Year Published: 2017 Number of citations: 2106 Primary or Secondary: Primary Publication Rating: CiteScore: 0.29 Rank: 377 Percentile: 27th In-Category: Mechanical Enginerring CiteScore Year: 2015 What themes were discussed in the Literature Review? Weibull stress, CTOD toughness, fracture assessment, FAD, constraint effect. What was the research question? Implication of case study for a wide plate specimen with the help of FAD (failure assessment diagram) approach. Design: Problem solving and case study. What was the finding? A higher accuracy assessment for fracture was implemented compared to standard assessment for fracture mechanics. What were the gaps? A complex problem solving involvement and lot of factors to be considered in order to prove the result to be practicable and viable. Reference Number: 12 Authors: M Z Arrifin Title of Article: Elastic-plastic fracture response of multiple 3-D interacting cracks in offshore pipelines subjected to large plastic strains Type: Journal Publication: Elsevier BV Year Published: 2017 Number of citations: 1364 Primary or Secondary: Primary Publication Rating: CiteScore: 1.84 Rank:38 Percentile: 85th In-Category: Engineering CiteScore Year: 2015 What themes were discussed in the Literature Review? Offshore pipeline, Non liner fracture assessment, multiple interacting cracks, CTOD What was the research question? Influence of crack parameters, nonlinear elastic-plastic fracture responses of a flawed pipeline and comparison with the BS7910:2013 code. Design: Simulation and comparison What was the finding? At high global strain, as a result of high biaxial loading; higher CTOD values are obtained when compared to tension loading. What were the gaps? CTOD is considered as a function of global strain and the simulation performed is based upon the parameters considered for the process and evaluation. Reference Number: 13 Authors: F V Antunes et al Title of Article: A numerical analysis of CTOD in constant amplitude fatigue crack growth Type: Journal Publication: Elsevier Year Published: 2016 Number of citations: 360 Primary or Secondary: Secondary Publication Rating: CiteScore:2.05 Rank:59 Percentile:85th In-Category: Applied Mathematics CiteScore Year:2015 What themes were discussed in the Literature Review? Fatigue Threshold, CTOD, Aluminium alloy, Crack closure What was the research question? Determination of relationship between da/dN and plastic CTOD for the AA6082-T6 aluminum alloy, independent of stress ratio, showing that the plastic CTOD is an interesting alternative to DK in the analysis of fatigue crack propagation Design: Problem solving and graphical representation What was the finding? Relationship between da/dN and plastic CTOD for the AA6082-T6 aluminum alloy, independent of stress ratio was found in a very well defined way. What were the gaps? Paris law was used as a basis for the research and further analysis is required in order to determine the accurate relationship between da /dN and plastic CTOD for the AA6082-T6 aluminum alloy. Reference Number: 14 Authors: Cole Cauthen et al Title of Article: Modelling fatigue crack growth behaviour in rolled AZ31 magnesium alloy using CTOD based strip yield modelling Type: Journal Publication: Elsevier limited Year Published: 2016 Number of citations: 2051 Primary or Secondary: Primary Publication Rating: CiteScore:2.79 Rank:37 Percentile:92nd In-Category: Mechanical Engineering CiteScore Year:2015 What themes were discussed in the Literature Review? CTOD, Magnesium alloys, Strip-yield, Micro structurally small crack growth What was the research question? Investigation of crack growth behaviour for fatigue in a rolled AZ31 magnesium plate and modelling Design: Experimental analysis and modelling What was the finding? For a rolled AZ31 magnesium plate, the amount of time for the values taken micro structurally are not practicable and the reason found out was the sequence of the cracks grown was plane. What were the gaps? The analysis was performed only for the rolled AZ31 magnesium plate and the result obtained clearly determines that the method employed is not practical. Reference Number: 15 Authors: Adriano Scheid et al Title of Article: The microstructure effect on the fracture toughness of ferritic Ni-alloyed steels Type: Article Publication: Elsevier BV Year Published: 2016 Number of citations: 11279 Primary or secondary: secondary Publication Rating: CiteScore:3.01 Rank:33 Percentile:93rd In-Category:Mechanical Engineering CiteScore Year:2015 What themes were discussed in the Literature Review? CTOD, M/A hard particles, Fracture toughness, EBSD What was the research question? Evaluation of fracture toughness for two nickel containing steels as an alternative in Carbon dioxide transporting pipelines for Enhanced Oil Recovery Design: Experimental analysis of microstructures What was the finding? Use if nickel is one of the reliable solutions to improve toughness in lower temperature and effectiveness of quenching and tempering What were the gaps? The result obtained is only viable when the microstructure for the specimen is properly optimized through heat treatment and rolling.