Analysis and Evaluation of FiberglassReinforced Plastic Pipe Using CAESAR II
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Agenda
!
Fiberglass pipe
!
Design using ISO 14692
!
Using C2
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How do these materials together define the Mechanical properties?
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Glass appearance in many ways !
Continuous roving "
Direct
"
Assembled Plain weave
!
Chopped strand mats
!
Continuous strand mats
!
Woven fabrics
!
"
Unidirectional
"
Bi-directional
"
Multi-axial
twill weave
Knitted
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How do these materials together define the Mechanical properties?
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Glass appearance in many ways !
Continuous roving "
Direct
"
Assembled Plain weave
!
Chopped strand mats
!
Continuous strand mats
!
Woven fabrics
!
"
Unidirectional
"
Bi-directional
"
Multi-axial
twill weave
Knitted
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Micro level analysis !
!
Failure modes to be evaluated: "
Failure of the fiber
"
Failure of the coupling agent layer
"
Failure of the matrix
"
Failure of the fiber-coupling agent bond
"
Failure of the coupling agent matrix bond
Reduced failure mode evaluation (lack of detailed knowledge of 2, 4 and 5) "
Fiber failure
"
Matrix failure
"
Fiber-matrix interface failure
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Stress level dependent on glass resin ratio !
Maximizing glass- resin ratio is not favorable for loads perpendicular to the glass
!
For larger glass resin ratios resin bridges become the weak spot Transverse resin stress intensity 18
16
14
12 y t i s n e t n i
s s e r t S
10
8
6
4
2
0 0
0.1
0.2
0.3
0.4 Mass fr action glass glass Transverse resin stress intensity
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0.5
0.6
0.7
0.8
Macro level analysis instead of Micro level !
!
!
Micro level analysis "
Feasible in concept
"
Not feasible in practice since many fibers randomly distributed and oriented
Mini level analysis. "
Evaluation of individual laminate layers
"
Laminate layer is considered a continuum with material properties and failure modes
"
Assessment by averaging over cross-section.
Macro level analysis. (actual state of the art) "
Evaluation of components made from multiple laminate layers
"
Series of layers act as a homogeneous material with estimated properties based on layer properties and winding angle
"
Failure analysis based on equivalent stress
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Hand Lay-up processing technique
Impregnated Reinforcement
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Spray-up processing technique
RESIN + ACCELERATOR
CATALYST + RESIN GLASS FIBRE
ROLLER
MOULD
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Filament winding processing technique
Fillers
Resin
Glass fibres
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Filament winding in action
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Helical winding processing technique
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Continuous filament winding processing technique Sand
Continuous glass fiber strand Chopped roving
Infrared oven
L = 12 m Diameters from 100 through 4000mm
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Continuous filament winding in action
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Continuous filament winding in action
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Continuous filament winding in action
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Continuous filament winding in action
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Before looking at the various design aspects first a little Fiberglass Quiz
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How does typical specific thermal expansion coefficients compare?
[ m/m/ C]
Stainless Steel
16.5
Carbon Steel
11.0
PVC
72.0
Polyethelene
120.0
= 50.0 [ m/m/ C]
Fiberglass
= 20.0 [ m/m/ C]
?
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How does typical specific thermal expansion coefficients compare?
[ m/m/ C]
Stainless Steel
16.5
Carbon Steel
11.0
PVC
72.0
Polyethelene
120.0
= 50.0 [ m/m/ C]
Fiberglass
= 20.0 [ m/m/ C]
?
CORRECT
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How does the typical (volumetric) Elasticity of fiberglass compare?
E [MPa]
Ductile iron
180.000
Steel
200.000
PVC
3.000
E = 20.000 MPa
Fiberglass
? E = 2.000 MPa
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How does the typical (volumetric) Elasticity of fiberglass compare?
E [MPa]
Ductile iron
180.000
Steel
200.000
PVC
3.000
CORRECT
E = 20.000 MPa
Fiberglass
? E = 2.000 MPa
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What is the GRP required free bend leg length?
!"#$%&"' )&"" *"+' ,"- ,"+-./ )0& 1220330'1.%0+ 0) ./" "451+6%0+7 91&13"."&6: ! ;+."&+1, 5&"66$&": ?",.1 @"357: ! ! C451+'%+- ,"-:
DIAMETER
<= >1&-7 A= 0B D= 3
GRP
GRP: 5m and 5.5m
STEEL GRP: 7m and 8m
150mm
?
4m
200mm
?
4.6m
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What is the GRP required free bend leg length?
!"#$%&"' )&"" *"+' ,"- ,"+-./ )0& 1220330'1.%0+ 0) ./" "451+6%0+7 91&13"."&6: ;+."&+1, 5&"66$&": ! ! ?",.1 @"357: C451+'%+- ,"-: !
DIAMETER
<= >1&-7 A= 0B D= 3
GRP
GRP: 5m and 5.5m
STEEL GRP: 7m and 8m
150mm
?
4m
200mm
?
4.6m CORRECT
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What is the typical wave speed in a Fiberglass pipe? K a
!
=
1+
Steel: 1000 - 1400m/s
D K t E GRP: 300 – 500m/s
K = fluid modulus of elasticity [Pa] = fluid density [kg/m 3] D = pipe diameter [mm] t = pipe wall thickness [mm]
GRP: 1300 – 1500m/s
E = pipe modulus of elasticity [Pa]
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What is the typical wave speed in a Fiberglass pipe? K a
!
=
1+
Steel: 1000 - 1400m/s
D K
CORRECT
t E GRP: 300 – 500m/s
K = fluid modulus of elasticity [Pa] = fluid density [kg/m 3] D = pipe diameter [mm] t = pipe wall thickness [mm]
GRP: 1300 – 1500m/s
E = pipe modulus of elasticity [Pa]
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Surge/Pressure Effects in GRP pipe in general are less than in metal pipe FIBERGLASS
STEEL
Pressure time history at valve (valve closure time: 2 secs)
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How does the effective material wall roughness of fiberglass compare?
[mm]
!
Ductile iron
0.03-0.1
Steel
0.1-0.3
PVC
0.05
= 0.05 mm
!
Fiberglass
?
= 0.001 mm
!
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How does the effective material wall roughness of fiberglass compare?
[mm]
!
Ductile iron
0.03-0.1
Steel
0.1-0.3
PVC
0.05
CORRECT
= 0.05 mm
!
?
Fiberglass
= 0.001 mm
!
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How large is the effective material axial strain due to internal pressure ?
[mm]
!
Ductile iron
0.005-0.01
Steel
0.005-0.01
= 0.15 %
!
Fiberglass
?
= 0.015 %
!
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How large is the typical material axial strain due to internal pressure ?
[mm]
!
Ductile iron
0.005-0.01
Steel
0.005-0.01
CORRECT
= 0.15 %
!
Fiberglass
?
= 0.015 %
!
For "a= 18 MPa !"# %&'%())) # )*%+, For T = 75 C= !T = 20 * 75 * 10 -6 = 0.15 %
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Agenda
!
Fiberglass pipe
!
Design using ISO 14692
!
Using C2
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ISO 14692 part 2 requires qualification of pipe and components Small bore products (typically pipe): !
Long term regression test (ASTM D 2992)
!
Delivers long-term strength
!
Takes approximately two years
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Example of a burst test
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Qualification of GRP – ASTM D 2992
) e r u s s e r p ( g o l
101
102
103
104 Time (hours)
105
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Qualification of GRP – ASTM D 2992
Failure ) e r u s s e r p ( g o l
101
102
103
104 Time (hours)
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105
Qualification of GRP – ASTM D 2992
Failure ) e r u s s e r p ( g o l
Failure
101
102
103
104 Time (hours)
105
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Qualification of GRP – ASTM D 2992
) e r u s s e r p ( g o l
101
102
103
104 Time (hours)
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105
Qualification of GRP – ASTM D 2992
) e r u s s e r p ( g o l
LTHP LCL
101
102
103
104 Time (hours)
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Qualification of GRP – ASTM D 2992
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105
Relation between long-term strength of piping and piping loads LONG-TERM STRENGTH
PIPING LOADS
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GRP-pipe systems often fail due to poor or no engineering !
./012 34 533" " 633" 7+,8 790": ;<;=:> ?:3>:=4< 0; ;0>"2: 0@ A04AB>C:4:@=012 D04:A=03@8 " ./012 7E+,8 790": ;<;=:> ?:3>:=4< 0; A3>"2:/ 0@ 1/012 D04:A=03@8
!
F5:@ " G>122 "14= 7H+,8 3C =5: C102B4:; 3AAB4; DB40@? 0@;=1221=03@ 34 3":41=03@ " I3;= 3C =5: C102B4:; 3AAB4 DB40@? 5
!
F5:4: " K30@=; 7&E,8 " L0M0@?; 7%),8 " 921@: "0": 7%,8
!
F5< " NB: =3 >1=:4012 D:C:A=; 7H(,8 " N:C:A=0O: 0@;=1221=03@ 7PE,8 " QO:4231D0@? 3C >1=:4012 DB: =3 ;534=A3>0@?; 0@ D:;0?@ 7PE,8
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Axially Overloaded pipe failure
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Axial tensile failure at reducer
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Typical failures adjacent to bend
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Failure in Pipe Adjacent to bend not in bend
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Large tee failure during pressure testing
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Axially Overloaded joint failure With large consequential damage due to waterhammer
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Construct a design envelope to assess pipe stresses against
2:1 load condition
s s e r t S l a i x A
Hoop Stress
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Effect of winding angle (netting theory
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! =
55 :
hoop : axial =
2:1
! =
63 :
hoop : axial =
4:1
! =
73 :
hoop : axial =
10:1
°
°
°
Construct a design envelope to assess pipe stresses against
2:1 load condition
s s e r t S l a i x A
Hoop Stress
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Construct a design envelope to assess pipe stresses against
Long-term envelope
s s e r t s l a i x A
Hoop stress
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Construct a design envelope to assess pipe stresses against
2:1 load condition
"qs
Long-term envelope ASTM D 2992-96 FPIAD,Wavistrongserie EST,ID 150mmpipe PL/PL,65°C,pressure, TUV
1000,0
M ea n
L CL
L PL
D at a
) g r a b ( e r u s s e r
100,0
p
10,0 1 0, 0E + 0 0
10 , 0 E + 0 1
1 0, 0E + 0 2
1 0, 0E + 0 3
1 0, 0E + 0 4
10 , 0 E + 0 5
1 0, 0E + 0 6
time (hrs)
s s e r t s l a i x A
Hoop stress
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Construct a design envelope to assess pipe stresses against
2:1 load condition
"qs
Long-term envelope Design envelope
ASTM D 2992-96 FPIAD,Wavistrongserie EST,ID 150mmpipe PL/PL,65°C,pressure, TUV
1000,0
M ea n
L CL
L PL
D at a
) g r a b ( e r u s s e r p
100,0
10,0 1 0, 0E + 0 0
10 , 0 E + 0 1
1 0, 0E + 0 2
1 0, 0E + 0 3
time (hrs)
s s e r t s l a i x A
Hoop stress f 2= 0.67
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1 0, 0E + 0 4
10 , 0 E + 0 5
1 0, 0E + 0 6
Several f2 safety factor values to create different design envelopes
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Construct a design envelope to assess pipe stresses against
2:1 load condition
Design envelope
s s e r t s l a i x A
Hoop stress f 2= 0.67
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Construct a design envelope to assess pipe stresses against
2:1 load condition
Design envelope
e r u s s e r p , l a i x a
s s e r t s l a i x A
Internal Pressure "
"
Hoop stress
" hoop, pressure
f 2= 0.67
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Construct a design envelope to assess pipe stresses against
2:1 load condition
" axial, bending
Design envelope
e r u s s e r p , l a i x a
s s e r t s l a i x A
"
Hoop stress
" hoop, pressure
f 2= 0.67
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Internal Pressure "
X Bending
Construct a design envelope to assess pipe stresses against
2:1 load condition
" axial, bending
Increase wall thickness!
Design envelope
e r u s s e r p , l a i x a
s s e r t s l a i x A
"
Hoop stress
" hoop, pressure
Internal Pressure "
X Bending
f 2= 0.67
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Construct a design envelope to assess pipe stresses against
2:1 load condition
Design envelope Internal Pressure "
e r u s s e r p , l a i x a
s s e r t s l a i x A
" Hoop stress
" hoop, pressure
f 3 © Intergraph 2014
f 2= 0.67
Construct a design envelope to assess pipe stresses against
2:1 load condition " axial, bending
Internal Pressure "
e r u s s e r p , l a i x a
s s e r t s l a i x A
"Bending
" Hoop stress
" hoop, pressure
f 3
f 2= 0.67
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Result: ISO 14692 design envelop that is producer and pipe specific
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Agenda
!
Fiberglass pipe
!
Design using ISO 14692
!
Using C2
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Configuration Options C2 for FRP !"#$%&' )&'*+, -./0 & ,*##'$+.1 3&45678889:& 3;4687<88 9:& 3;3&45=> 3;3& ?;&48=@A B:/$,,/C D&E$/F G+C,$E"45A
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Select FRP material while building your model Activates Orthotropic material model of C2 Requires several parameters for axial and hoop direction ! Elastic Modulus ! Poisson Ratio ! Shear modulus Be careful with diameters and wallthicknesses Use Fitting data from supplier to ensure the right laminate thickness is entered everywhere
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Check the special execution parameters
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