JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 71

xxx

Composite materials:
unlocking mystery with invariants

By

A common, understandable invariant-based framework has been
discovered that can rate all CFRPs and their processes, simplify
design and testing, and lower the barrier of acceptance.

stePhen W. tsai, Professor researCh
eMeritus, dePartMent of aeronautiCs &
astronautiCs, stanford university
Jose daniel d. Melo, Phd Professor of Materials
engineering federal university of rio grande do norte

l

n a speech delivered at CompositesWorld's Carbon Fiber 2014
conference on December 10, 2014,
John Byrne, head of materials and
structures for Boeing Commercial
Airplanes, talked about the lessons
learned from their pioneering effort
in using CFRP for the 787 primary
structures, and cited explicitly, "Composites in general are poorly understood... therefore not employed
optimally." We hope that our effort in
the new book "Composite Materials
Design and Testing" can demystify
the often unnecessary complexity of
composite materials and offer more
orderly, practical solutions.
There are simpler and easier approaches that will lead to new opportunities in design and testing. In
traditional practice, ply properties are
the starting point. There are 4 elastic
constants (Ex, Ey, nx, and Es) and 5
anchors for strength (X, X', Y, Y' and
S). Ex and X and X' are the easiest to
measure; the others are more difficult. Shear modulus and strength can

hardly be measured directly. These
properties are treated like random
variables. What is worse, designers
demand their allowable values. It is
our plan to show that these properties are all related, and can be cast
into a general framework. With such a
framework, only the easiest test of [0]
be needed, from which all laminate
stiffness and strength can be inferred.
The unifying entity is the trace of a
material.

Trace is the one
Trace is the sum of the diagonal
components of the stiffness matrix of
metals and composites; i.e., Tr [A] =
A11 + A22 + 2A66. This is an exact
mathematical relation, not just a convenient collection of the elastic components. This invariant (that has no
directional preference or variation) is
the one and only number needed to
completely characterize the stiffness
of all composite laminates formed by
carbon fibre-reinforced plies. Instead
of the building block approach that
goes from the bottom of a pyramid
to the top, we see trace as the shining
light from the top of the pyramid that
unlocks the stiffness of all composite
materials. It is that simple and cor-

rect; not an empirical fit.
Testing of coupons in the bottom row
of the traditional strength pyramid
can be replaced by data from [0]
specimens; we can go directly to
as-built elements and components.
Trace defines the upper bound of
laminate performance and sets a
standard to rate the quality of design,
manufacturing and testing. It makes
composites as clear and straightforward as metals. Each material has a
value in trace, which is easy to estimate for unidirectional or fabric plies,
and their laminates.
In Table 1, the value of trace for 16
unidirectional CFRP are ranked
in descending order in the second
column from the left. With an order
of 1% accuracy, these 16 common
CFRP materials can be represented
by a master ply using their median
values. The trace-normalized effective
stiffnesses E1 and their coefficient
of variation for 7 laminates defined
based on the percentage of [0],
[±45] and [90] plies are shown in
the bottom 2 rows. For example, the
effective stiffness E1 of [π/4] is 0.34
x Trace. For IM7/9773 with a trace
value of 218 GPa, E1° = 0.34 x 218 =

No95 March 2015 / jec

composites magazine 71



JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015

Cover
Edito
Point of view: Raw materials - Quality, innovation, reliability and safety are exactly what we deliver
Contents
Companies & Business
Carbon fibre - “I am confident in the future of Zhongfu Shenying”
Automotive - “Composites are going to be more important again with the batteries...”
Agenda of Events
Applications
Thermoplastics - Evaluating the viability of thermoplastic composite pressure vessel
Motorcycle - Epoxy adhesive for a Harley-Davidson motorbike
Thermoplastics - New GRP enclosure for extreme environments
Market
Europe - The European upturn continues
Reinforcement - Glass fabrics demand will grow
Natural fibre - Securing the supply of technical flax for the composite industry
SPECIAL JEC EUROPE 2015
12th International JEC Conferences: Knowledge and networking
The know-how to develop tomorrow’s lightweight production technology
JEC Innovation Awards Program 2015
Innovations report 2015: France, country guest of honor
Design
Automation
Insert
CNC router
Tooling
Design and testing
Research & Development
Short natural fibres - Study on short natural fibres for composites
Biocomposites - Adhesion between flax fibre and a biobased thermoset matrix
Technology & Innovations
Lightweighting - Meeting the challenges for lighter cars with innovative products
CFRP - Carbon composites: Material systems with improved mechanical behaviour for various industries
Epoxy - DFCM: a new step forward in composite mass production
Graphene - Graphene-based high-performance composites via plasma functionalisation
Thermoset - Reformable epoxy adhesive film
Sizing - «We are constantly developing new products»
Index
In the world
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - Cover
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 2
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - Edito
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - Point of view: Raw materials - Quality, innovation, reliability and safety are exactly what we deliver
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 5
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - Contents
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 7
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 8
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - Carbon fibre - “I am confident in the future of Zhongfu Shenying”
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 10
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 11
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 12
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - Automotive - “Composites are going to be more important again with the batteries...”
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 14
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 15
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - Agenda of Events
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 17
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 18
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - Thermoplastics - Evaluating the viability of thermoplastic composite pressure vessel
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 20
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 21
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - Motorcycle - Epoxy adhesive for a Harley-Davidson motorbike
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 23
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 24
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - Thermoplastics - New GRP enclosure for extreme environments
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 26
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - Europe - The European upturn continues
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 28
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 29
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - Reinforcement - Glass fabrics demand will grow
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 31
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - Natural fibre - Securing the supply of technical flax for the composite industry
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 33
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - SPECIAL JEC EUROPE 2015
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 12th International JEC Conferences: Knowledge and networking
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 36
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 37
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - The know-how to develop tomorrow’s lightweight production technology
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 39
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 40
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 41
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - JEC Innovation Awards Program 2015
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 43
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 44
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 45
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 46
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 47
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 48
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 49
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 50
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 51
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 52
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - Innovations report 2015: France, country guest of honor
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 54
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 55
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 56
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 57
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 58
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 59
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - Design
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 61
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - Automation
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 63
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - Insert
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 65
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - CNC router
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 67
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - Tooling
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 69
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 70
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - Design and testing
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 72
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 73
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 74
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 75
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 76
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 77
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - Short natural fibres - Study on short natural fibres for composites
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 79
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 80
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 81
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - Biocomposites - Adhesion between flax fibre and a biobased thermoset matrix
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 83
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 84
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - Lightweighting - Meeting the challenges for lighter cars with innovative products
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 86
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 87
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - CFRP - Carbon composites: Material systems with improved mechanical behaviour for various industries
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 89
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 90
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 91
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - Epoxy - DFCM: a new step forward in composite mass production
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 93
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 94
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - Graphene - Graphene-based high-performance composites via plasma functionalisation
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 96
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 97
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - Thermoset - Reformable epoxy adhesive film
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 99
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 100
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 101
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - Sizing - «We are constantly developing new products»
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 103
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 104
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 105
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - Index
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - In the world
JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 108
https://www.nxtbook.fr/newpress/jeccomposites/jcm2107_141
https://www.nxtbook.fr/newpress/jeccomposites/jcm2105_140
https://www.nxtbook.fr/newpress/jeccomposites/jcm2103_139
https://www.nxtbook.fr/newpress/jeccomposites/jcm-experts-digest-additive-manufacturing-2020
https://www.nxtbook.fr/newpress/jeccomposites/jcm2101_138
https://www.nxtbook.fr/newpress/jeccomposites/jcm2011_Special_Issue4
https://www.nxtbook.fr/newpress/jeccomposites/jcm2011_137
https://www.nxtbook.fr/newpress/jeccomposites/jcm2009_136
https://www.nxtbook.fr/newpress/jeccomposites/jcm2007_135
https://www.nxtbook.fr/newpress/jeccomposites/jcm_2020_Q1_Innovation_Report
https://www.nxtbook.fr/newpress/jeccomposites/jcm2005_Special_Issue3
https://www.nxtbook.fr/newpress/jeccomposites/jcm2005_134
https://www.nxtbook.fr/newpress/jeccomposites/jcm2003_133
https://www.nxtbook.fr/newpress/jeccomposites/jcm2001_132
https://www.nxtbook.fr/newpress/jeccomposites/jcm1911_Special_Issue2
https://www.nxtbook.fr/newpress/jeccomposites/jcm1911_131
https://www.nxtbook.fr/newpress/jeccomposites/jcm1909_130
https://www.nxtbook.fr/newpress/jeccomposites/jcm1907_129
https://www.nxtbook.fr/newpress/jeccomposites/jcm1905_128
https://www.nxtbook.fr/newpress/jeccomposites/jcm1903_Special_Issue1
https://www.nxtbook.fr/newpress/jeccomposites/jcm1903_127
https://www.nxtbook.fr/newpress/jeccomposites/jcm1901_126
https://www.nxtbook.fr/newpress/jeccomposites/jcm1811_125
https://www.nxtbook.fr/newpress/jeccomposites/jcm1810_124
https://www.nxtbook.fr/newpress/jeccomposites/jcm1808_123
https://www.nxtbook.fr/newpress/jeccomposites/jcm1807_122
https://www.nxtbook.fr/newpress/jeccomposites/jcm1805_121
https://www.nxtbook.fr/newpress/jeccomposites/jcm1804_120
https://www.nxtbook.fr/newpress/jeccomposites/jcm1803_119
https://www.nxtbook.fr/newpress/jeccomposites/jcm1802_119-Supplement_Innovation_Report
https://www.nxtbook.fr/newpress/jeccomposites/jcm1801_118
https://www.nxtbook.fr/newpress/jeccomposites/jcm1711_117
https://www.nxtbook.fr/newpress/jeccomposites/jcm1710_116
https://www.nxtbook.fr/newpress/jeccomposites/jcm1708_115
https://www.nxtbook.fr/newpress/jeccomposites/jcm1707_114
https://www.nxtbook.fr/newpress/jeccomposites/jcm1706_113
https://www.nxtbook.fr/newpress/jeccomposites/jcm1704_112
https://www.nxtbook.fr/newpress/jeccomposites/jcm1703_111
https://www.nxtbook.fr/newpress/jeccomposites/jcm1701_110
https://www.nxtbook.fr/newpress/jeccomposites/jcm1611_109
https://www.nxtbook.fr/newpress/jeccomposites/jcm1610_108
https://www.nxtbook.fr/newpress/jeccomposites/jcm1608_107
https://www.nxtbook.fr/newpress/jeccomposites/jcm1607_106
https://www.nxtbook.fr/newpress/jeccomposites/jcm1605_105
https://www.nxtbook.fr/newpress/jeccomposites/jcm1604_104
https://www.nxtbook.fr/newpress/jeccomposites/jcm1603_103
https://www.nxtbook.fr/newpress/jeccomposites/jcm1601_102
https://www.nxtbook.fr/newpress/jeccomposites/jcm1511_101
https://www.nxtbook.fr/newpress/jeccomposites/jcm1510_100
https://www.nxtbook.fr/newpress/jeccomposites/jcm1509_99
https://www.nxtbook.fr/newpress/jeccomposites/jcm1507_98
https://www.nxtbook.fr/newpress/jeccomposites/jcm1505_97
https://www.nxtbook.fr/newpress/jeccomposites/jcm1504_96
https://www.nxtbook.com/newpress/jeccomposites/jcm1503_95
https://www.nxtbook.com/newpress/jeccomposites/jcm1501_94
https://www.nxtbook.com/newpress/jeccomposites/jcm1412_93
https://www.nxtbook.com/newpress/jeccomposites/jcm1410_92
https://www.nxtbook.com/newpress/jeccomposites/jcm1409_91
https://www.nxtbook.com/newpress/jeccomposites/jcm1406_90
https://www.nxtbook.com/newpress/jeccomposites/jcm1405_89
https://www.nxtbook.com/newpress/jeccomposites/jcm1404_88
https://www.nxtbook.com/newpress/jeccomposites/jcm1403_87
https://www.nxtbook.com/newpress/jeccomposites/jcm1401_86
https://www.nxtbook.com/newpress/jeccomposites/jcm1311_85
https://www.nxtbook.com/newpress/jeccomposites/jcm1310_84
https://www.nxtbook.com/newpress/jeccomposites/jcm1308_83
https://www.nxtbook.com/newpress/jeccomposites/jcm1307_82
https://www.nxtbook.com/newpress/jeccomposites/jcm1305_81
https://www.nxtbook.com/newpress/jeccomposites/jcm1304_80
https://www.nxtbook.com/newpress/jeccomposites/jcm1303_79
https://www.nxtbook.com/newpress/jeccomposites/jcm1301_78
https://www.nxtbook.com/newpress/jeccomposites/jcm1212_77
https://www.nxtbook.com/newpress/jeccomposites/jcm1210_76
https://www.nxtbook.com/newpress/jeccomposites/jcm1208_75
https://www.nxtbook.com/newpress/jeccomposites/jcm1207_74
https://www.nxtbook.com/newpress/jeccomposites/jcm1206_73
https://www.nxtbook.com/newpress/jeccomposites/jcm1204_72
https://www.nxtbook.com/newpress/jeccomposites/jcm1203_71
https://www.nxtbook.com/newpress/jeccomposites/jcm1201_70
https://www.nxtbook.com/newpress/jeccomposites/jcm1111_69
https://www.nxtbook.com/newpress/jeccomposites/jcm1110_68
https://www.nxtbook.com/newpress/jeccomposites/jcm1108_67
https://www.nxtbook.com/newpress/jeccomposites/jcm1107_66
https://www.nxtbook.com/newpress/jeccomposites/jcm1105_65
https://www.nxtbook.com/newpress/jeccomposites/jcm1104_64
https://www.nxtbook.com/newpress/jeccomposites/jcm1103_63
https://www.nxtbook.com/newpress/jeccomposites/jcm1101_62
https://www.nxtbook.com/newpress/jeccomposites/jcm1011_61
https://www.nxtbook.com/newpress/jeccomposites/jcm1010_60
https://www.nxtbook.com/newpress/jeccomposites/jcm1009_59
https://www.nxtbook.com/newpress/jeccomposites/jcm1006_58
https://www.nxtbook.com/newpress/jeccomposites/jcm1005_57
https://www.nxtbook.com/newpress/jeccomposites/jcm1004_56
https://www.nxtbook.com/newpress/jeccomposites/jcm1003_55
https://www.nxtbook.com/newpress/jeccomposites/jcm1001_54
https://www.nxtbook.com/newpress/jeccomposites/jcm0911_53
https://www.nxtbook.com/newpress/jeccomposites/jcm0910_52
https://www.nxtbook.com/newpress/jeccomposites/jcm0909_51
https://www.nxtbook.com/newpress/jeccomposites/jcm0907-08_50
https://www.nxtbook.com/newpress/jeccomposites/jcm0906_49
https://www.nxtbook.com/newpress/jeccomposites/jcm0904_48
https://www.nxtbook.com/newpress/jeccomposites/jcm0903_47
https://www.nxtbook.com/newpress/jeccomposites/jcm0901_46
https://www.nxtbook.com/newpress/jeccomposites/jcm0811_45
https://www.nxtbook.com/newpress/jeccomposites/jcm0810_44
https://www.nxtbook.com/newpress/jeccomposites/jcm0809_43
https://www.nxtbook.com/newpress/jeccomposites/jcm0807_42
https://www.nxtbook.com/newpress/jeccomposites/jcm0806_41
https://www.nxtbook.com/newpress/jeccomposites/jcm0805_40
https://www.nxtbook.com/newpress/jeccomposites/jcm0803_39
https://www.nxtbook.com/newpress/jeccomposites/jcm0801_38
https://www.nxtbook.com/newpress/jeccomposites/jcm0712_37
https://www.nxtbook.com/newpress/jeccomposites/jcm0710_36
https://www.nxtbook.com/newpress/jeccomposites/jcm0709_35
https://www.nxtbook.com/newpress/jeccomposites/jcm0707_34
https://www.nxtbook.com/newpress/jeccomposites/jcm0706_33
https://www.nxtbookmedia.com