Stacking sequence optimization in composite tubes under ...
Transcript of Stacking sequence optimization in composite tubes under ...
Stacking sequence optimization in composite tubes under internalpressure based on genetic algorithm accounting for progressivedamageAlmeida Jr, J. H. S., Ribeiro, M. L., Tita, V., & Amico, S. C. (2017). Stacking sequence optimization in compositetubes under internal pressure based on genetic algorithm accounting for progressive damage. CompositeStructures, 178, 20-26. https://doi.org/10.1016/j.compstruct.2017.07.054
Published in:Composite Structures
Document Version:Peer reviewed version
Queen's University Belfast - Research Portal:Link to publication record in Queen's University Belfast Research Portal
Publisher rightsCopyright 2017 Elsevier.This manuscript is distributed under a Creative Commons Attribution-NonCommercial-NoDerivs License(https://creativecommons.org/licenses/by-nc-nd/4.0/), which permits distribution and reproduction for non-commercial purposes, provided theauthor and source are cited.
General rightsCopyright for the publications made accessible via the Queen's University Belfast Research Portal is retained by the author(s) and / or othercopyright owners and it is a condition of accessing these publications that users recognise and abide by the legal requirements associatedwith these rights.
Take down policyThe Research Portal is Queen's institutional repository that provides access to Queen's research output. Every effort has been made toensure that content in the Research Portal does not infringe any person's rights, or applicable UK laws. If you discover content in theResearch Portal that you believe breaches copyright or violates any law, please contact [email protected].
Download date:01. Oct. 2021
1
STACKING SEQUENCE OPTIMIZATION IN COMPOSITE TUBES UNDER INTERNAL
PRESSURE BASED ON GENETIC ALGORITHM ACCOUNTING FOR PROGRESSIVE
DAMAGE
José Humberto S. Almeida Jr.a*, Marcelo L. Ribeirob, Volnei Titab, Sandro C. Amicoc
aLeibniz-Institut für Polymerforschung Dresden e.V., Department of Composite Materials,
Hohestraße 6, 01067 Dresden, Germany
bDepartment of Aeronautical Engineering, São Carlos School of Engineering, University of
São Paulo, São Carlos/SP, Brazil
cPPGE3M, Federal University of Rio Grande do Sul, Av. Bento Gonçalves, 9500. 91501-970
Porto Alegre/RS, Brazil
___________________________________________________________________________
Abstract
Due to the large number of design variables for laminate composite structures, the use of an
optimum stacking sequence is a key step in the design of a structure with the most suitable
mechanical properties. This work presents a genetic algorithm (GA) for the optimization of
the stacking sequence to improve strength of a cylindrical shell under internal pressure. The
GA, which is associated to a meso-scale damage model, was written in Fortran and later
linked to a Finite Element (FE) package to simulate composite damage and failure. Two
scenarios were considered: i) without restriction, where an ideal situation is simulated; and ii)
with manufacturing restrictions, accounting for limitations on feasible winding angles. The
results show that progressive failure analysis generates asymmetric and unbalanced laminates
*Corresponding author: [email protected]; [email protected].
Phone: +49 351 4658 1423; Fax: +49 351 4658 362
2
in both cases. Furthermore, the simulations with manufacturing restrictions present internal
pressure strengths lower than the idealized case, providing more realistic results.
Keywords: optimization; genetic algorithm; composite shell; progressive failure; finite
element method; filament winding.
___________________________________________________________________________
1. Introduction
The advent of high-performance carbon fibers has enabled the evolution of composite
tubes for structural applications. These structures are typically manufactured by filament
winding (FW) and have advantages compared to metallic-based conventional materials, such
as high stiffness- and strength-to-weight ratios, allied to high corrosion strength [1]. For an
efficient design of composite tubes for a particular application, avoiding extra costs with re-
manufacturing and testing, appropriate knowledge of the effect of laminate layup on the
required mechanical properties is essential.
Even though numerical analyses are a useful tool in the design of filament wound
structures, most decisions are based on processing experience and experiments. That is, most
parts are not optimized for optimum ply-orientation considering progressive damage/failure
phenomenon [2]. Indeed, efficient stacking sequence optimization algorithm associated with
progressive failure of the laminas is not yet well established and most contributions in the
literature have used first ply failure criterion to optimize filament wound structures.
Optimization of the winding sequence for a composite tube is a challenge because the
optimal composite structure depends on the physical and mechanical performance of the
materials, shape, and manufacturing constraints, therefore generally requires computer-
assisted design tools [3]. The possibility of easily winding the continuous fibers to match the
particular stress needs and boundary conditions in a composite structure for optimized
3
performance gives an extra advantage in the use of composite materials compared to
traditional ones, such as steel or aluminum [4].
Popular algorithms for the optimization of filament wound composite tubes and
pressure vessels include genetic algorithm (GA) [5], simulated annealing [6] and artificial
immune system [7]. Optimization usually focuses on the improvement of strength/weight
ratio, reliability and lifetime of a composite shell by designing optimum winding angles and
thicknesses, as in the case of the current study. A GA is a search algorithm based on
mechanics of natural selection and genetics which simulates natural evolution so that multiple
design points evolve to converge to a global optimum solution [8]. In every new generation, a
new set of artificial strings is created using pieces from the fittest of the old generation, based
on a non-deterministic scheme. A key advantage of this method is that it uses discrete design
variables by nature [9].
Several studies have dealt with optimization in composite laminates. For instance,
Rahul et al. [10] used GA to optimize the weight of graphite/aramid/epoxy laminates. Jing et
al. [11] optimized the stacking sequence for composite laminates using a multicriteria
objective function with respect to the critical buckling. Irisarri et al. [12] applied a
multiobjective stacking sequence optimization for composite plates and concluded that non-
conventional ply orientations may lead to improved optimal designs compared to classical
angles (0°, ±45° and 90°). Zu et al. [13] applied GA to find the best non-geodesic trajectory
for filament wound toroidal pressure vessels. Francescato et al. [14] used GA to study
composite pressure vessels overwrapping a metallic liner (type III COPV) under internal
pressure and concluded that optimal design is mainly dependent on the calculation strategy,
particularly considering first-ply or last-ply failure design objective. However, these authors
did not focus on optimum stacking sequence, which is the main motivation and contribution
of the current study.
4
Studies dealing with optimization procedures for filament wound structures evaluating
fiber path predictions, structural analyses, weight reduction and design procedures are not
easily found, especially accounting for progressive damage/failure evolution. Thus, the scope
of this study is to optimize the stacking sequence of filament wound composite cylindrical
shell under internal pressure using a genetic algorithm connected to a mesoscale damage
finite element model accounting for progressive failure. Simulations with and without
manufacturing restrictions of feasible winding angles were also carried out.
2. Finite element model
Structural modeling was performed based on finite element (FE), using Abaqus™ 6.14
commercial software platform. Non-linear geometry was considered in all cases since large
displacements and strains can take place during the simulations. The composite tubes/
cylinders (381 mm length and 136 mm diameter) were modeled using an equivalent single
layer (ESL) four node reduced integration shell element (S4R) with hourglass control (Figure
1). This element was chosen in order to reduce simulation time and avoid numerical issues.
The composite layers were modeled as conventional shell with Simpson’s thickness
integration rule and three integrations points in each of the ten layers.
Internal pressure was applied on the inner surface of the shell and on the inner surface
of the flanges located at the ends of the structure (Figure 1) and axial displacements of both
flanges were restricted. As the damage model applied is very step-size-dependent, a
convergence study was performed and, after mesh sensibility study, a typical mesh with 1,672
elements and 1,716 nodes was selected. A maximum increment size of 5% for applied internal
pressure was used throughout the simulation.
In order to predict material failure, the proposed damage model was compiled as a
UMAT (User Material Subroutine) and linked to Abaqus™. The material properties of the
5
carbon/epoxy laminates were experimentally measured and reported in a previous study [15]
(Table 1). The damage model parameters used may be found in [16,17].
Figure 1. Applied loading and boundary conditions, typical mesh and FE element used.
Table 1. Representative material properties used as input in the numerical models [15].
Symbol Description Value
Ela
stic
pro
per
ties
E1 (GPa) Longitudinal elastic modulus 129.3
E2 = E3 (GPa) Transversal elastic modulus 9.11
= Poisson’s ratio in plane 1-2 0.32
Poisson’s ratio in plane 2-3 0.35
G12 = G13 (GPa) In-plane shear modulus 5.44
G23 (GPa) Transverse shear modulus in plane 2-3 2.10
Str
ength
s
Xt (MPa) Longitudinal tensile strength 1409.9
Yt (MPa) Transverse tensile strength 42.5
Xc (MPa) Longitudinal compressive strength −740.0
Yc (MPa) Transverse compressive strength −140.3
Spl (MPa) In-plane shear strength 68.9
2.1 Damage model
6
In order to evaluate progressive failure of the tubes, a damage model based on the
work of Ribeiro et al. [18] was applied. The model regards the composite lamina as under
plane stress state and damage is considered uniform throughout the laminate thickness [19].
Regarding fiber failure modeling, a unidirectional carbon/epoxy laminate under tensile
loading in the fiber direction (𝜎11) is considered linear elastic with brittle fracture. The model
assumes that fiber behavior is not influenced by the damage state of the matrix and, for tensile
loading in the fiber direction, the maximum stress criterion is used to identify fiber failure. On
the other hand, under compressive longitudinal loading, fiber behavior is considered linear
elastic until a specified value is reached (𝑋𝐶0), and non-linear elastic after that. To model the
damage process in the fiber, an internal damage variable 𝑑1 is used.
Concerning matrix modeling, the damage process in the matrix of a unidirectional
quasi-flat filament wound laminate is essentially dominated by transverse loading (𝜎22) and
shear loading (𝜏12), and non-linear behavior is reported due to inelastic strains and damage
[20]. Thus, two internal matrix damage variables were used, 𝑑2 (related to 𝜎22) and 𝑑6
(related to 𝜏12). Based on Continuous Damage Mechanics (CDM), the hypothesis of effective
stress links the damage variables to the stresses [19]. Table 2 summarizes the constitutive law
for each type of failure in the damage model herein presented.
A full description of this model can be found in [18], where the authors used
traditional flat composite coupons to identify the required damage parameters through well-
known mechanical tests. This model has also been successfully applied to flat filament wound
laminates under 3-point bending [17] and to carbon/epoxy filament wound composite tubes
under hydrostatic external pressure [21] or radial compression [22].
The damage model is very effective in predicting progressive failure when loading
involves essentially in-plane stresses, since it intrinsically considers these stresses. Also, it
requires low computational cost and simple tests to identify the parameters, making the model
7
very attractive. As a drawback, if out-of-plane shear stresses are significant and the dominant
failure is driven by delaminations, the model might not predict failure well.
Table 2. Summary of the constitutive laws for each type of failure in the damage model used.
Failure type Failure criteria Degradation law
Fiber tension 𝜎11𝑋𝑡
≤ 1 𝐸11 = 0
Fiber compression |𝜎11|
𝑋𝐶0≤ 1 𝐸11 =
𝑋𝐶0|𝜀11|
(1 − ℎ(𝜀11)) + ℎ(𝜀11)𝐸110
Matrix tension 𝑓 > 0 𝑑2 = 𝐴(𝜃)𝑌2 + 𝐵(𝜃)
Matrix compression 𝑓 > 0 𝐸22 =𝜎22𝑦|𝜀22|
(1 − 𝑓(𝜀22)) + 𝑓(𝜀22)𝐸220
Shear 𝑓 > 0 𝑑6 = 𝐶(𝜃)𝑌6 + 𝐷(𝜃)
In Table 2, ℎ(𝜀11) is obtained from the fitting of stress-strain plots for 0° specimens
under compressive loading, and 𝑓 is defined as shown in Eq. (1).
𝑓 = √𝜎222 + 𝜏12
2 − (−𝑆12𝑦 +2𝑆12𝑦
1+(|𝜎22|
𝜎220⁄ )
3) (1)
3. Optimization process via genetic algorithm
Genetic algorithms use the evolution theory concept to search the global optimal [9].
Each possible solution of a problem is considered an “individual” with an encoded
“chromosome”. This codification is obtained by a “genes” group that keeps individual’s
characteristic and there is a particular value for each “Individual” associated with its problem
solution potentiality, which is usually known as “fitness”. A method based on binary numbers
allows crossing individuals represented by a number that saves its genes characteristics.
8
To start the optimization process, an initial “Population” of individuals is randomly
generated. This generation can decode its chromosome and apply its fitness function after new
individuals are generated by combining individuals of the previous population. This process
can be divided into “Individual” selection, “Crossover” and “Mutation”. The first one is
related with method and criteria, which are used to choose individuals. The crossover creates
new individuals by changing genes with selected individuals, whereas mutation ensures that,
with low probability, a few genes are modified and a new search space can be explored,
thereby increasing the chance of achieving a global optimum. The process is repeated until a
new complete population is established, finishing a generation. The algorithm is further
iterated if a termination criterion is not satisfied. The identification process is based on the
conventional GA as described by Goldberg [9] and implemented in MatLab software®. The
population is randomly generated and, at each generation, reproduction continues until the
size of this population is doubled. By sorting the new doubled population, the scheme
discards the half with the worst fitness values.
3.1 Angle layer optimization
The GA works creating one angle population at random, based on the angle range of
interest. These angles need to be qualified according to how it may be more able than others,
to achieve the project objective. When this is carried out by the FE model, population
crossing can produce a new generation, which would be again qualified by the FE model, and
this process repeats until the best generation is found, as shows the flowchart in Figure 2.
After each crossing, the algorithm makes elitism pre-definition, comparing the new
generation with the previous one, and selecting the best members to compose the next
generation to be crossed. For the genetic algorithm, mutation probability is 1% and the
crossover probability is 100%.
9
Regarding the optimization scheme presented in Figure 2, two routines were
developed separately: (i) the FE routine is represented by the steps described within the green
dashed square box; and ii) the optimization Routine, represented by the steps within the blue
dashed square box. Regarding FE Routine (i), the first step is to develop a .CAE FE model,
which is generated by a Python script. After that, processing of the FE model is carried out
by solver of Abaqus, exporting an initial stacking sequence as a .TXT file. Then, the
optimization process (ii) begins with the definition of the fitness function, which establishes
the basis for selection of pairs of individuals that will be mated during reproduction. GA
optimization is then defined by maximizing the fitness function defined, where a new set of
approximation by selecting individuals respecting the level of the fitness at each new
generation. This process leads to the evolution of population of individuals, and then the
results exported as a .CSV file.
Figure 2. Flowchart of the optimization process.
Optimization has been performed with and without manufacturing restrictions. In the
FW process, the machine needs a minimum length to contour the turnaround zones, in which
10
both winding angle and thickness vary to allow the pay-out eye to turn to the opposite
longitudinal direction in the programmed symmetric angle (+φ or −φ). In the current study,
the mandrel is 420 mm long and, for the friction factors used, the equipment is not able to
wind within −20° and +20° due to the limited turnaround length available.
In an idealized scenario, if the FW machine was capable of winding any angle, the
simulation may run without restriction. Although this scenario is not possible for the actual
mandrel, it was also studied since alternative strategies, such as extended mandrel and/or
insert pins at its extremities, might make lower angles possible. The first scenario is expected
to produce structures with higher internal pressure strength, as an upper bound, whereas the
second scenario should produce more realistic results in terms of internal pressure strengths.
The first 20 layups were randomly chosen for both scenarios. After several
simulations, the results for 30 generations with 20 individuals each converged, with no further
increase in maximum internal pressure with the increase in generation number. In all, 600
finite element simulations were carried out in each case.
4. Results and discussion
Figure 3(a) shows the results of the optimization process without manufacturing
restrictions. After 30 generations with 20 individuals each, the improvement in maximum
internal pressure strength is of 14.4 MPa (from 31.46 MPa to 45.85 MPa). In fact, this value
was reached after 8 generations only. Also, average and minimum fitness display a significant
improvement, converging to the maximum pressure at higher number of generations.
Moreover, even though strength does not increase further, there are many layups able to
withstand that maximum applied internal pressure.
11
Figure 3. Fitness evolution for simulations without layup restriction with a randomly chosen
initial angle (a), and with a pre-defined initial angle of 0° (b) or 45° (c).
Table 3 shows the first generation layup (randomly chosen) and the 30th generation.
The optimization process yields an asymmetric layup, and several of the winding angles
shown are not feasible due to the mandrel restrictions. Furthermore, if a particular layer is
forced into the initial population, the generation procedure takes less time to reach the
maximum internal pressure supported by the laminate, as shown in Figure 3(b) for an initial
angle of 0o. Nevertheless, similar pressure levels were reached compared to the previous
random simulation (Figure 3(a)). In Figure 3(c), the maximum internal pressure is achieved in
the 16th generation, later than the other two cases (as shown in figures 3(a) and (b)), but the
pressure level achieved is similar to the other cases.
Table 3. Optimum stacking sequence for the 1st and 30th generations for the simulations
without layup restriction and randomly chosen initial angle.
12
Simulations with a higher number of generations with the initial angle randomly
chosen have also been performed for comparison (Figure 4). Although the obtained stacking
sequence is quite similar to the one shown in Table 3, the results from the simulations with
more generations provided better results, with higher pressure levels. This optimum stacking
sequence is shown in Table 3.
It is clear that an asymmetric winding sequence yielded the best results considering
progressive failure analyses, that is, a symmetric laminate is not the best option for composite
tubes under internal pressure based on last ply failure approach. Nevertheless, most
publications report that the optimum winding angle for composite shells under hydrostatic
internal pressure is symmetric ±55° (considering first ply failure approach). In such case, the
current results are quite relevant, and aid in a paradigm break for the design of composite
tubes under internal pressure, where unusual angles and non-symmetric laminates are found.
Figure 4. Fitness evolution for simulations without layup restriction with a randomly chosen
initial angle (50 generations, 20 individuals each).
Layer 1 Layer 2 Layer 3 Layer 4 Layer 5 Layer 6 Layer 7 Layer 8 Layer 9 Layer 10
Gen. 1 −36.8º −76.5º 9.9º −86.5º −5.7º −14.2º 41.1º −17.0º 60.9º −19.8º
Gen. 30 −86.5º 14.2º 34.0º −72.3º −68.0º −7.1º 65.2º −19.8º 65.2º 35.4º
13
Indeed, in a last-ply failure approach, after the first ply fails, unbalancing of the
laminate appears, and a symmetric laminate loses its symmetry. Hence, even though the
laminate is originally symmetric, it becomes asymmetric as the failure process initiates. These
results can be related to those of Irisarri et al [12], who found that non-conventional ply
angles for composite plates under compression and shear loadings behave better than
laminates using 0°, ±45° and 90° angles. Another consequence of the unbalancing of the
laminate is that the coupling stiffness [𝑩] matrix begins to have nonzero elements. Likewise,
the 𝐴16 and 𝐴26 elements from the [𝑨] matrix are not null anymore.
Regarding the results for simulations performed with mandrel restrictions, i.e. for a
more realistic scenario, the optimization process yields the results presented in Figure 5 for a
fitness evolution over 30 generations. This optimization uses the same conditions applied for
the first case (30 generations with 20 individuals each, and first 20 individuals randomly
chosen).
The resulting optimum layup is quite different from the previous ones. Nevertheless,
asymmetric laminates are also found, corroborating the previous results. In such asymmetric
and unbalanced laminates, even more unique couplings may arise and even result in fully
anisotropic behavior in that bending, stretching, shearing and twisting responses are fully
coupled. In the laminates herein studied, they exhibit coupling between mechanical
deformations generated by in-plane shear loads and moments, along with in-plane shear
strains and curvatures inherent to cylindrical structures [23].
As the initial layup was randomly chosen, maximum pressure (38.35 MPa) is already
achieved at the first generation (Figure 5). On the other hand, average and minimum fitness
increase over the generations.
14
Figure 5. Fitness evolution for simulations with layup restriction and randomly chosen initial
angle (30 generations, 20 individuals each).
Table 4 presents then the layup for first and last generation. As well as for the case
without restrictions, there is no single layup for the cylinder that would lead to maximum
internal pressure. Indeed, the layup may differ significantly from one generation to the next
and the cylinder would still support that pressure level. Here again, optimization lead to an
asymmetric laminate. Finally, without manufacturing limitations, the maximum internal
pressure is around 7.5 MPa higher than those with manufacturing restrictions limitations
(45.85 MPa and 38.35 MPa, respectively), which means that processing parameters (in this
case, mandrel length, can have a significant effect on the predictions.
Table 4. Optimum stacking sequence for the 1st and 30th generations for the simulations with
layup restriction and randomly chosen initial angle.
Layer 1 Layer 2 Layer 3 Layer 4 Layer 5 Layer 6 Layer 7 Layer 8 Layer 9 Layer 10
Gen. 1 −48.7º −79.5º 28.3º −87.2º −24.4º −31.0º 52.5º −33.2º 68.0º −35.4º
Gen. 30 −87.2º 35.9º 47.0º 69.1º 32.7º −57.5º −36.5º −54.2º −49.8º −44.2º
15
5. Conclusions
An optimization process using a genetic algorithm was employed to find the optimum
winding angle for filament wound composite cylinders under internal pressure. The FE model
accounted for progressive failure considering, or not, manufacturing angle restrictions
(between −20° and +20°) due to the limited mandrel length. For the first scenario, without
manufacturing restrictions, the composite cylinders reached an internal pressure of up to
45.85 MPa. The simulations taking into account angle limitations and allowing the first 20
individuals to be randomly chosen quickly converged, and one of them reached the maximum
pressure in the first generation. In addition, the progressive failure analysis allowed the
optimization process to yield asymmetric and unbalanced laminates in both scenarios.
Therefore, strain-curvature coupling between layers is verified, and bending load acts on the
structure once the cylinder is pressurized.
Finally, based on the last ply failure approach adopted, this research aids in a paradigm
break considering that it suggests asymmetric and non-conventional angles as the best
solution for internally pressurized composite tubes, contrasting to the well-known ±55°
winding angle recommendation (for first ply failure approach).
Acknowledgements
The authors are grateful to CNPq and AEB for the financial support. Marcelo L.
Ribeiro would like to thank FAPESP (project 2015/13844-8) and Volnei Tita acknowledges
the financial support from CNPq (projects 401170/2014-4 and 310094/2015-1).
References
16
[1] Almeida Jr. JHS, Faria H, Marques AT, Amico SC. Load sharing ability of the liner in
type III composite pressure vessels under internal pressure. J Reinf Plast Compos
2014;33(24):2274-2286.
[2] Kim CU, Kang J-H, Hong CS, Kim CG. Optimal design of filament wound structures
under internal pressure based on the semi-geodesic path algorithm. Compos Struct
2005;67(4):443–452.
[3] Cagdas IU. Optimal design of filament wound truncated cones under axial compression.
Compos Struct 2017;170:250-260.
[4] Hernández-Moreno H, Douchin B, Collombet F, Choquese D, Davies P. Influence of
winding pattern on the mechanical behavior of filament wound composite cylinders under
external pressure. Compos Sci Technol 2008;68 (3–4):1015–1024.
[5] Wang L, Kolios A, Nishino T, Delafin P-L, Bird T. Structural optimisation of vertical-axis
wind turbine composite blades based on finite element analysis and genetic algorithm.
Compos Struct 2016;153:123-138.
[6] Kirkpatrick S, Gelatt CD, Vecchi MP. Optimization by simulated annealing. Science
1983;220(4598):671–680.
[7] Medzhitov R. Recognition of microorganisms and activation of the immune response.
Nature 2007;449:819–826.
[8] Fu X, Ricci S, Bisagni C. Minimum-weight design for three dimensional woven
composite stiffened panels using neural networks and genetic algorithms. Compos Struct
2015;134:708-715.
[9] Goldberg DE. Genetic algorithm in search, optimization, and machine learning. Addison-
Wesley Publishing Company; 1989.
[10] Rahul, Chakraborty D, Dutta A. Optimization of FRP composites against impact induced
failure using island model parallel genetic algorithm. Compos Sci Technol 2005;65(13):2003-
2013.
[11] Jing Z, Sun Q, Silberschmidt VV. Sequential permutation table method for optimization
of stacking sequence in composite laminates. Compos Struct 2016;141:240-252.
[12] Irisarri F-X, Bassir DH, Carrere N, Maire J-F. Multiobjective stacking sequence
optimization for laminated composite structures. Compos Sci Technol 2009;69(7-8):983-990.
17
[13] Zu L, Koussios S, Beukers A. Design of filament-wound circular toroidal hydrogen
storage vessels based on non-geodesic fiber trajectories. Int J Hydrogen Energ
2010;35(2):660-670.
[14] Francescato P, Gillet A, Leh D, Saffré P. Comparison of optimal design methods for type
3 high-pressure storage tanks. Compos Struct 2012;94(6):2087-2096.
[15] Almeida Jr. JHS, Souza SDB, Botelho EC, Amico SC. Carbon fiber-reinforced epoxy
filament-wound composite laminates exposed to hygrothermal conditioning. J Mater Sci
2016;51(9):4697-4708.
[16] Tita V, Carvalho J, Vandepitte D. Failure analysis of low velocity impact on thin
composite laminates: experimental and numerical approaches. Compos Struct
2008;83(4):413–428.
[17] Ribeiro ML, Tita V, Vandepitte D. Damage model and progressive failure analyses for
filament wound composite laminates. Appl Compos Mater 2013;20(5):975–992.
[18] Ribeiro ML, Tita V, Vandepitte D. A new damage model for composite laminates.
Compos Struct 2012;94(2):635–642.
[19] Herakovich C. Mechanics of Fibrous Composites, Wiley Publisher, Vol. 1, 1998.
[20] Puck A and Schürmann H. Failure analysis of FRP laminates by means of physically
based phenomenological models. Compos Sci Technol 1998;58(7):1045-1067.
[21] Almeida Jr. JHS, Ribeiro ML, Tita V, Amico SC. Damage and failure in carbon/epoxy
filament wound composite tubes under external pressure: Experimental and numerical
approaches. Mater Des 2016;96:431–438.
[22] Almeida Jr. JHS, Ribeiro ML, Tita V, Amico SC. Damage modeling for carbon fiber
reinforced epoxy filament wound composite tubes under radial compression. Compos Struct
2017;160:204–210.
[23] Lagace PA, Jensen DW, Finch DC. Buckling of unsymmetric composite laminates.
Compos Struct 1986;5(2):101-123.