Process-induced strain and distortion in curved composites. Part I: Development of fiber-optic strain monitoring technique and analytical methods

Takagaki, Kazunori; Minakuchi, Shu; Takeda, Nobuo

doi:10.1016/j.compositesa.2017.09.020

Cited by 43 publications

(11 citation statements)

References 30 publications

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“…The research in this field has been focused on studying cure behaviour and post-manufacturing process quality assessment, aiming to optimize its production and reduce costs. The main mechanisms causing shape distortions are thermal anisotropy, resin polymerization shrinkage, tool-part interaction, resin flow and compaction and temperature gradients [1] [2]. An effective way of understanding the magnitude of these effects on the manufacturing stages is monitoring key process parameters.…”

Section: Introductionmentioning

confidence: 99%

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ELADINE: sensor monitoring and numerical model approach for composite material wing box shape distortions prediction

Torre-Poza

Pinto

Grandal

et al. 2022

IOP Conf. Ser.: Mater. Sci. Eng.

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Out-of-Autoclave technologies are emerging as cost-effective alternatives to autoclave cure prepreg. However, their implementation in aerospace industry is still presenting many challenges. A common problem is the shape distortions that results in geometry mismatches with the tool. A way to avoid this and ensure a good final quality part is identifying the mechanisms that induce these deformations and optimize the manufacturing process of each component with the aim of reducing the production of faulty parts. The main objective of ELADINE project is to provide a method for shape distortions prediction on composite integral structures using an experimental-numerical approach. Different manufacturing parameters were monitored using Fiber Bragg Grating (FBG) sensors and DC-dielectric (DC) sensors and the resulting part geometry was examined by means of 3D coordinate analysis. The study performed for LRI (Liquid Resin Infusion) manufactured parts and the scenarios considered for the calibration of a Finite Element Method (FEM) based simulation tool are presented in the article. The resulting model will be implemented in a sub-scale demonstrator and, eventually, in a full 7-meter composite wing-box.

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Section: Introductionmentioning

confidence: 99%

“…In order to decouple these signals, the fiber can be encapsulated in a steel or silica capillary tube so that strain is not transmitted to the fiber and the wavelength shift is only due to temperature variations. T and ε signals can be decoupled using equation ( 2) [2] [3].…”

Section: Introductionmentioning

confidence: 99%

ELADINE: sensor monitoring and numerical model approach for composite material wing box shape distortions prediction

Torre-Poza

Pinto

Grandal

et al. 2022

IOP Conf. Ser.: Mater. Sci. Eng.

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“…Subsequently, Kravchenko et al [ 74 ] conducted the experimental and numerical study of deflection in bi-lamina strips caused by thermal and chemical shrinkage, occurring at various stages of the cure cycle. Takagaki et al [ 75 ] in 2017 used Fiber Bragg Grating (FBG) sensors to experimentally measure through-thickness normal and shear strains. The results obtained were used to analyze the curing process and the development of spring-in in the L-shaped carbon-fiber-reinforced polymer (CFRP) part at different stages of the cure process, which are associated with chemical and thermal shrinkage.…”

Section: Introductionmentioning

confidence: 99%

Modeling Spring-In of L-Shaped Structural Profiles Pultruded at Different Pulling Speeds

et al. 2021

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Cure-induced deformations are inevitable in pultruded composite profiles due to the peculiarities of the pultrusion process and usually require the use of costly shimming operations at the assembly stage for their compensation. Residual stresses formed at the production and assembly stages impair the mechanical performance of pultruded elements. A numerical technique that would allow the prediction and reduction of cure-induced deformations is essential for the optimization of the pultrusion process. This study is aimed at the development of a numerical model that is able to predict spring-in in pultruded L-shaped profiles. The model was developed in the ABAQUS software suite with user subroutines UMAT, FILM, USDFLD, HETVAL, and UEXPAN. The authors used the 2D approach to describe the thermochemical and mechanical behavior via the modified Cure Hardening Instantaneous Linear Elastic (CHILE) model. The developed model was validated in two experiments conducted with a 6-month interval using glass fiber/vinyl ester resin L-shaped profiles manufactured at pulling speeds of 200, 400, and 600 mm/min. Spring-in predictions obtained with the proposed numerical model fall within the experimental data range. The validated model has allowed authors to establish that the increase in spring-in values observed at higher pulling speeds can be attributed to a higher fraction of uncured material in the composite exiting the die block and the subsequent increase in chemical shrinkage that occurs under unconstrained conditions. This study is the first one to isolate and evaluate the contributions of thermal and chemical shrinkage into spring-in evolution in pultruded profiles. Based on this model, the authors demonstrate the possibility of achieving the same level of spring-in at increased pulling speeds from 200 to 900 mm/min, either by using a post-die cooling tool or by reducing the chemical shrinkage of the resin. The study provides insight into the factors significantly affecting the spring-in, and it analyzes the methods of spring-in reduction that can be used by scholars to minimize the spring-in in the pultrusion process.

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“…In situ monitoring technology has been used for a long time in composite material processing. Embedded sensors such as optical fibers, 25 piezoelectric sensors, 26,27 and nanomaterials sensors [28][29][30] are widely used in the in situ curing monitoring and structure health monitoring. For example, Moretti et al used fiber Bragg grating (FBG) sensors to monitor the preparation, reparation and inservice of composites.…”

Section: Introductionmentioning

confidence: 99%

Influence of resin curing cycle on the deformation of filament wound composites by in situ strain monitoring

Chen

Huan

et al. 2021

High Performance Polymers

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The residual stress of metal liners wrapped by composite materials has a significant influence on the service performance of rotating parts, such as flywheel rotors and motor jackets. However, the deformation of the liners, the flow of resins, and the temperature variation during the winding process make it difficult to predict and control this residual stress. In this paper, the process-induced strains were monitored online by a strain gauge with the help of a wireless strain meter. The evolution of this strain during the manufacturing process was fully discussed. A rapid curing resin system was used and its curing properties were tested by differential scanning calorimetry. The mechanical properties of the resin matrix and its composite were characterized. The effect of the curing cycle on the evolution of the residual strain was discussed in detail through comparative experiments. The experimental results show that the use of infrared radiation has a significant advantage regarding residual stress accumulation. This advantage is greater when carbon fiber is used than when glass fiber is used. The prestress in composites of glass fiber and carbon fiber increases by 5.9% and 41.7%, respectively, after cooling.

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Process-induced strain and distortion in curved composites. Part I: Development of fiber-optic strain monitoring technique and analytical methods

Cited by 43 publications

References 30 publications

ELADINE: sensor monitoring and numerical model approach for composite material wing box shape distortions prediction

ELADINE: sensor monitoring and numerical model approach for composite material wing box shape distortions prediction

Modeling Spring-In of L-Shaped Structural Profiles Pultruded at Different Pulling Speeds

Influence of resin curing cycle on the deformation of filament wound composites by in situ strain monitoring

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