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2.6.3 Optical Fibre Sensor (OFS) ...................................................................... 37 2.6.4 SHM using Electrical Strain Gauges ........................................................ 40 2.7 Introduction to Finite Element Analysis (FEA) ............................................... 42 2.7.1 Stress Concentration Factor (SCF) and Stress Intensity Factor (SIF) Measurement in Pipeline .......................................................................... 45 2.8 Experimental Approach ................................................................................... 49 2.9 Why is SHM important in the composite repair? ............................................ 51 2.10 Summary and Conclusions .............................................................................. 53 3 FINITE ELEMENT ANALYSIS (FEA) IN THE COMPOSITE BASED PIPELINE REPAIR ................................................................................................................... 55 3.1 Introduction ...................................................................................................... 55 3.2 Objectives ........................................................................................................ 55 3.3 Model and Other Parameters Selection............................................................ 56 3.4 Fundamentals of Modelling in Finite Element Analysis ................................. 57 3.4.1 Element type selection .............................................................................. 57 3.4.2 Mesh refinement ....................................................................................... 60 3.4.3 Types of Algorithms ................................................................................. 63 3.4.4 Artificial constraints ................................................................................. 66 3.5 The influence of pressure on the FEA pipe model .......................................... 71 3.5.1 Pressure test on the converged model....................................................... 71 3.6 To determine other factors‘ influences on the Numerical Model .................... 74 3.6.1 Introduction .............................................................................................. 74 3.6.2 Comparison of Results ............................................................................. 74 3.6.3 Concluding Remarks ................................................................................ 79 3.7 The simulation of blunt defect behaviour in a thin walled cylinder (FE Pipe Model) .............................................................................................................. 79 viii
3.7.1 Introduction .............................................................................................. 79 3.7.2 Geometry of Notches in FE Pipe Model .................................................. 80 3.7.3 Internal Pressure ....................................................................................... 82 3.7.4 Concluding Remarks ................................................................................ 89 3.8 The development of the composite repair modelling ...................................... 89 3.8.1 Introduction .............................................................................................. 89 3.8.2 The theory of Homogenisation in the Triaxial Woven Fabric (TWF) composite .................................................................................................. 89 3.8.3 The study of predicted elastic constant in the TWF composite repair modelling .................................................................................................. 90 3.8.3.1 Constitutive Lamination Theory ....................................................... 96 3.9 Numerical Stress Analysis of Composite Repair ............................................. 99 3.9.1 Stress concentration comparison of the pipe with and without the repair ................................................................................................................ 100 3.9.1.1 Numerical Stress Results ................................................................. 108 3.9.1.2 Concluding Remarks ....................................................................... 120 3.10 Numerical Strain Analysis of Composite Repair ........................................... 121 3.10.1 Strain study on the chosen models prior to composite repair ................. 121 3.10.2 Strain study on the composite repair ...................................................... 122 3.11 Summary and Conclusions ............................................................................ 125 4 STRUCTURAL HEALTH MONITORING APPROACH IN STRESS STRAIN ANALYSIS OF COMPOSITE BASED PIPELINE REPAIR .............................. 128 4.1 Introduction .................................................................................................... 128 4.2 Data acquisition of Composite-based Pipeline Repair ................................... 129 4.2.1 Introduction ............................................................................................ 129 4.2.2 Strain Gauge Selection and Criteria ....................................................... 131 4.2.3 Calculation of Principal Strains using a Rectangular Strain Gauge Rosette ................................................................................................................ 132 ix
Page 1: CRANFIELD UNIVERSITY MAHADI ABD MUR
Page 4 and 5: ABSTRACT One of the most common pro
Page 7: TABLE OF CONTENTS ABSTRACT ........
Page 11: 5.6 Summary and Conclusions .......
Page 14 and 15: Figure 3.1: Schematic diagram of th
Page 16 and 17: Figure 5.4: The average temperature
Page 18 and 19: NOMENCLATURES ACFM Alternating Curr
Page 21 and 22: 1 INTRODUCTION One of the most comm
Page 23 and 24: 1.1 Objectives Knowing this backgro
Page 25 and 26: The methodology of this integrated
Page 27 and 28: Chapter 6 contains the summary and
Page 29 and 30: period of the major part of the exi
Page 31 and 32: Figure 2.2: Reported interest in de
Page 33 and 34: Figure 2.4: Dent damage caused by v
Page 35 and 36: presented current practices, recent
Page 37 and 38: Energy Workforce Sdn Bhd (2011) cla
Page 39 and 40: available provides real time detect
Page 41 and 42: 2.3.3 Reliability Analysis of Infor
Page 43 and 44: Figure 2.9: Pipeline failure probab
Page 45 and 46: 2.3.3.1 NDT Reliability and POD cur
Page 47 and 48: increase in the yield limit of stee
Page 49 and 50: the SCC assessment in their integri
Page 51 and 52: Manufacturers such as Walkers Techn
Page 53 and 54: Company L.P, 2005); Aquawrap ® pro
Page 55 and 56: monitoring, inspection, and damage
Page 57 and 58: 2.6.2 Aims of Structural Health Mon
Page 59 and 60:
Figure 2.16: Application fields and
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egistered by the piezoelectric sens
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discretization error. Round-off err
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notches and Neuber‘s is better fo
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maximum local stress at discontinui
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De Carvalho (2005) concludes that t
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accurate simulation of loading espe
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Based on the above facts, the opera
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3 FINITE ELEMENT ANALYSIS (FEA) IN
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Figure 3.2: Schematic diagram of th
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In this modelling work (i.e. compos
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This partition toolset also helps u
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Figure 3.6: Mesh control using Swee
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Figure 3.7: Schematic representatio
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discretization. Therefore, in this
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According to Staten et al. (2010b),
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3.5 The influence of pressure on th
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each pressure value remains constan
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Axial Stress, σa (S22) was referre
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Figure 3.14 shows a graph of analyt
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the notch defect is found to be in
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One of the contributions of this st
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Table 3.4: Convergence tests on var
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Figures 3.16 and 3.17 show that the
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Figure 3.20 shows that as the relat
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3.7.4 Concluding Remarks A biaxial
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yarns change and lateral contact be
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For predicting E2 and Gl2, a number
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Where: Ar = weight of one sheet of
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Where; The Stiffness matrix is trad
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simulations for the hoop strain at
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Figure 3.24: Finding the hoop stres
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Table 3.8: The effect of repair len
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four up to 18 layers. In this study
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hoop and axial stress concentration
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Table 3.11: Predicted Elastic Const
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Table 3.13: Axial Stress v/s L/W ra
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Hoop Stress (MPa) Figure 3.3: Hoop
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However, Frost (2008) and Alexander
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Table 3.17: Ratio of Axial Stress N
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axial load (e.g. buried pipelines t
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3.10 Numerical Strain Analysis of C
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Figure 3.36 shows the contours befo
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Stress Concentration Factor 2 1.8 1
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In fact, for Notch 40 with 18 plies
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this second approach (i.e. the expe
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4.2.2 Strain Gauge Selection and Cr
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Finally, a method used to calculate
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Where, and are the maximum and mini
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should be between 20 and 28 bar and
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welded weld neck flange at both end
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Figure 4.7: Sensor and heating elem
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Figure 4.9: A summary of data acqui
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One of the objectives of doing this
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Figure 4.14: A schematic diagram of
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Table 4.1: Strain gauge readings at
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microstrain 3.00E-04 2.50E-04 2.00E
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However, the axial load transfer is
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Mircostrain 500 450 400 350 300 250
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Since the defect is not a flat notc
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Again, the epoxy resin plays a sign
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Table 4.4: Study at the defect area
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Mircostrain 300 250 200 150 100 50
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Mircostrain 600 500 400 300 200 100
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14.25% in hoop strain and 23.5% in
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consideration for the selection of
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5.4 Methodology of Thermal Expansio
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Figure 5.1: Some preventive measure
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5.4.1 The Fundamentals of the Therm
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5.5 Analysis of Results 5.5.1 The t
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Thermal Output (strain ) 0.0002 0.0
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(Strain ,ε) Figure 5.12: Coefficie
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(Strain ,ε) 0.0002 0.00018 0.00016
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Table 5.1: The strain readings afte
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maximum shear strain increase as th
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The above results show that shear s
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shear strains becomes more stable a
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for future safe design and operatio
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has been fully cured. Poor surface
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6.3 Primary PhD Achievements The ea
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In Chapter 5, the CTE was determine
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ASM International (2002), "Thermal
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Bucinell, R. B. (2001), Calculating
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Proceedings of OMAE'01 20th Interna
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Greenwood, R. (2002), UKOPA Pipelin
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Kotrechko, S. A., Krasovskii, A. Y.
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Mousavi, S. E., Xiao, H. and Sukuma
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Raju, I. S. and Newman, J. C. (1986
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Tennyson, R. C. and Mufti, A. A. (2
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Xue, L., Widera, G. E. O. and Sang,
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General Technical Specifications: T
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Photos of the Design and Build of t
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Composite Installation Process usin
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APPENDIX 3 - STRAIN GAUGE INSTALLAT
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Figure 7: Mylar tape was stuck onto
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Figure 19: Repeating the above proc
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2) Electrical Insulation Test Resul
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