Virtual autoclave implementation for improved composite part quality and productivity

Dumont, François; Fröhlingsdorf, Werner; Weimer, Christian

doi:10.1007/s13272-013-0072-1

Cited by 10 publications

(7 citation statements)

References 5 publications

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“…For more complex shapes, as they usually occur during the production of composite parts, numerical methods like CFD have to be applied, which simulate the complete fluid flow within the autoclave. While there are examples for simulation methods in literature, [1][2][3] only few approaches for the validation of the calculated flow field have been presented, yet. 3 The lack of validation can be attributed to the difficulty of using existing equipment for the measurement of flow fields within the autoclave.…”

Section: Theoretical Backgroundmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…In summary, the heat transfer into the CFRP parts is temperature and pressure dependent and is also highly dependent on the location of the CFRP part inside the autoclave which is characterized by a 3D air flow pattern depending on the construction of the autoclave itself. [1][2][3] A numerical process optimization by changing part positions or adaptation of the cure cycle for the set of CFRP parts loaded into the autoclave is a difficult task and requires complex numerical models combining fluid dynamics, heat transfer in solid materials and cure kinetics of the used resin system in general.…”

Section: Introductionmentioning

confidence: 99%

“…In literature, a broad set of models are presented starting from simple 1D representations of heat transfer into the part assuming a constant temperature distribution 3,4 and heat transfer inside the autoclave, analytical models derived by measuring the heat transfer inside the autoclave using calorimeters, 5 up to the use of fluid dynamics calculations to characterize the air flow pattern 1,3 to finally predict the degree of cure and optimize the cure cycle for any given loading. On the other hand, the knowledge of the degree of cure and the temperature distribution inside the CFRP part gives also the opportunity to predict the process-induced distortion of CFRP parts which is also shown to be dependent on the transient temperature distribution inside the part.…”

Section: Introductionmentioning

confidence: 99%

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Simulation and validation of air flow and heat transfer in an autoclave process for definition of thermal boundary conditions during curing of composite parts

Bohne

Frerich²,

Jendrny

et al. 2017

Journal of Composite Materials

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Aerospace carbon fibre-reinforced components are cured under high pressure (7 bar) and temperature in an autoclave. As in an industrial environment, the loading of an autoclave usually changes from cycle to cycle causing different thermal masses and airflow pattern which leads to an inhomogeneous temperature distribution inside the carbon fiber-reinforced plastic part. Finally, the overall process can be delayed and the part quality can be compromised. In this paper, the heat transfer in a small laboratory autoclave has been investigated using calorimeter measurements and a fluid dynamic model. A complex turbulent flow pattern with locally varying heat transfer coefficient has been observed. Especially, the pressure and the inlet fluid velocity have been identified as sensitive process parameters. Further finite element simulations with adjusted boundary conditions provide accurate results of the curing process inside of the components for selective process control. The heat transfer coefficient has been found to be almost stationary during the observed constant pressure autoclave process allowing a separated investigation of the heat transfer coefficient and the curing of the components. The presented method promises therefore a detailed observation of the autoclave process with reduced computational effort.

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Section: Theoretical Backgroundmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Simulation and validation of air flow and heat transfer in an autoclave process for definition of thermal boundary conditions during curing of composite parts

Bohne

Frerich²,

Jendrny

et al. 2017

Journal of Composite Materials

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show abstract

“…Specific mechanical properties of carbon fibre-reinforced polymer (CFRP) laminates are excellent [1,2]: these composite materials are therefore widely used in high-tech industries like the automobile and aerospace industries [3]. CFRP laminates can be ready-to-shape manufactured using numerous advanced and automated technologies like autoclave or closed mould vacuum bagging [4,5]. Nevertheless, after the curing processes, there are still many micro-and macro-geometrical features that have to be machined mechanically.…”

Section: Introductionmentioning

confidence: 99%

Comparative analysis of wobble milling, helical milling and conventional drilling of CFRPs

Pereszlai

Geier

2020

Int J Adv Manuf Technol

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Due to its excellent specific mechanical properties, carbon fibre-reinforced polymer (CFRP) composite is a widely used structural material in the aerospace industry. However, this material is difficult to cut, mainly due to its inhomogeneity and anisotropic features and because of the strong wear effects of its carbon fibres. In the scope of aerospace industrial uses of this material, thousands of holes have to be machined for purposes of assembly. Nevertheless, conventional drilling technologyeven if special drilling tools are usedis only moderately able to manufacture good quality holes. Wobble milling is a novel advanced hole-making technology, which has been developed to minimize machining-induced geometrical defects like delamination or uncut fibres. The main objective of the present paper is to compare wobble milling, helical milling and conventional drilling technologies concerning unidirectional CFRPs. In addition, the kinematics of wobble milling technology is discussed in detail. In the scope of this paper, numerous machining experiments were conducted in unidirectional CFRPs: herein the impact of the type of cutting tool and of process parameters on the quality of machined holes are analysed and discussed (diameter of holes, circularity error and characteristics of uncut fibres). During these investigations, experimental data were evaluated with the help of digital image processing (DIP) and with the help of analysis of variance (ANOVA) techniques. Experimental results show that the amount of uncut fibres can significantly be minimized through the application of wobble milling technology.

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An efficient thermal cure profile design method for autoclave curing of large size mold

Dolkun

Wang

2021

Int J Adv Manuf Technol

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Virtual autoclave implementation for improved composite part quality and productivity

Cited by 10 publications

References 5 publications

Simulation and validation of air flow and heat transfer in an autoclave process for definition of thermal boundary conditions during curing of composite parts

Simulation and validation of air flow and heat transfer in an autoclave process for definition of thermal boundary conditions during curing of composite parts

Comparative analysis of wobble milling, helical milling and conventional drilling of CFRPs

An efficient thermal cure profile design method for autoclave curing of large size mold

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