Tooling Development for Thermoplastic Composites Thermoforming Process Based on FEM Analysis – a Rib Case Study (original) (raw)
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Polymers
This research work investigated the influence of the press molding manufacturing process on the mechanical properties, both for thermoplastic and thermosetting fiber reinforced composite materials. The particular geometry of the case study, called Double Dome, was considered in order to verify the behavior of the Thermoplastic and Thermosetting prepreg in terms of shell thickness variation and fibers shear angle evolution during the thermoforming process. The thermoforming simulation was performed using LS-DYNA® Finite Element Analysis (FEA) code, and the results were transferred by Envyo®, a dedicated mapping tool, into a LS-DYNA® virtual model for the structural simulation. A series of Double Dome specimens was produced with industrial equipment, and a bending experimental test was been carried on. Finally, a numerical-experimental correlation was performed, highlighting a significant forecast of the mechanical properties for the considered component.
Processing of continuous fibre reinforced thermoplastics
2012
Towpregs based on different fibres and thermoplastic matrices were processed for highly demanding and more commercial applications by different composite processing technologies. In the technologies used, compression moulding and pultrusion, the final composite processing parameters were studied in order to obtain composites with adequate properties at industrial compatible production rates. The produced towpregs were tested to verify its polymer content and degree of impregnation. The obtained results have shown that the coating line enabled to produce, with efficiency and industrial scale speed rates, thermoplastic matrix towpregs that may be used to manufacture composites for advanced and larger volume commercial markets.
This study investigated the effects of different heat treatments on continuous fiberreinforced thermoplastic (CFRTP) 's. CFRTP composite is produced using fused deposition modeling (FDM), which is one of the additive manufacturing methods. Polylactic acid (PLA) was used as a matrix, and carbon fibers (3K) were utilized as reinforcement material. First, CFRTP filament was produced on a specially designed melt impregnation line. Afterward, test samples were manufactured via a conventional 3D printer. Then, heat treatments (re-melting in salt, microwave oven, oven) were applied to the produced samples, and the effects of these processes on mechanical properties were investigated. Three-point bending tests were used to investigate the mechanical properties of the test samples. As a result of the heat treatments applied to the CFRTP specimens, flexural stresses between 200 and 220 MPa was achieved. The highest bending stress was obtained by re-melting in salt. As a result of the heat treatments, the stress values are similar, but the re-melting in salt application exhibited a more rigid behavior.
Stamp forming of thermoplastic composites: effect of radius and thickness on part quality
2014
An experimental study on stamp forming of thermoplastic composites is presented. The stamp forming process is used to shape high performance thermoplastic composites made of carbon fibre-reinforced Polyphenylene Sulphide (CF/PPS). The target geometry in this study is a Sshape. The effects of various blank and tool parameters, e.g., blank stacking sequence, blank thickness and tool radius, on part quality are investigated. In addition, effects of processing parameters such as consolidating pressure, holding time and tool temperature on part quality are also investigated. Four tool radii are used in addition to a few stamping pressures and holding times. Part quality is evaluated through thickness variation measurements throughout a part and degree of crystallinity. Microscopy and Differential Scanning Calorimetry (DSC) are used to this end. Finally, the mechanical performance of the moulded parts is evaluated under four-point bending testing. Recommendations are made in order to achi...
The International Journal of Advanced Manufacturing Technology, 2021
Thermoplastic based composite materials are increasingly gaining the interest of many engineering sectors, among them the automotive. Their unique features, resulted by the thermoplastic matrix characteristics, such as their recyclability and their formability have given new perspectives in their use. Among the most promising fabrication methods of thermoplastic composite components is the thermoforming process, the press forming of a heated semi-nalized composite plate. This method, although requires a quite simple working station and can be implemented in mass production, demonstrates a series of disadvantages on the quality of the product. Among them, the variation of the thickness, formation of wrinkles and overall undesired deformations are considered as defects that decrease the quality not only from the esthetical but also from the structural point of view. In the present work, a numerical analysis of the thermoforming process is conducted when applied to a box-shaped geometry. As an input for the material behavior during the process, mechanical tests are conducted at elevated temperatures. The at and curved critical zones of the component are identi ed and an analysis of the effect of the temperature and the crosshead speed of the molds on the thickness distribution are examined as well as the overall residual stress eld. The results indicate a strong dependency of the quality of the product by these parameters of the process.
2021
Üretim parametreleri, özellikle havacılık sınıfı polieter keton keton (PEKK)/karbon fiber (CF) kompozitlerde termoplastik kompozitlerin mekanik özelliklerinde önemli bir rol oynamaktadır. Sunulan bu çalışmada, farklı sıcaklık değerlerinde konsolide edilen PEKK/CF kompozitlerinin mekanik özellikleri değerlendirilmiştir. Benzer bir basınç profiliyle, kür sıcaklığının PEKK/CF kompozit laminatın gerilme, laminalar arası kesme dayanımı (ILSS) ve düzlem içi kesme dayanımı (IPSS) üzerindeki etkisini belirlemek için çeşitli kür sıcaklıkları uygulandı. Kompozit laminatlardaki gözeneklilik, delaminasyon ve boşluk içeriği, Ultrasonik Test yoluyla NDT yöntemi kullanılarak karakterize edildi. Bu makale, bir polieter keton keton (PEKK)/karbon fiber (CF) kompozitleri kullanılarak otoklav işlemiyle farklı kürleme sıcaklığı numunelerinin karşılaştırılması için üretim kupon test numunelerinin bazı güncel sonuçlarını sunmaktadır. PEKK/CF'nin gerilme ve laminalar arası kayma mukavemeti özellikleri, sırasıyla 350°C, 375°C ve 400°C'de farklı kürleme sıcaklık geçmişleri ile hazırlanacak şekilde çalışılmıştır. Yapılan testler ideal kürleme sıcaklığını 400°C derece olarak belirlemiştir.
2021
Forming simulations are a cost-effective solution to mitigate process-induced defects. The models developed to simulate the forming process require material property data for the dominant deformation mechanisms: intra-ply shear, bending, and inter-ply friction. These mechanisms are considered independent, and material property data has to be derived from experimental data for each mechanism separately. However, it is known that the material response to the deformation mechanisms is correlated, as the choice of matrix, fibre, and reinforcement influences the response to all mechanisms. Over the past years a large variety of thermoplastic composites have been characterised, covering a broad field of applications in automotive and aerospace industry. This makes it possible to start correlating the forming behaviour of thermoplastic composites. In this study, the effect of the constituents of a composite on the forming behaviour is analysed. To this end, a Bayesian cross-classified mult...
Effect of carbon fibre on reinforcement of thermoplastics using FDM and RSM
Journal of Thermoplastic Composite Materials, 2019
Continuous fibre-reinforced composites have significant industrial importance and usage. However, they are limited by design considerations and high-cost manufacturing operations. This article presents a way forward to utilize Fused Deposition Modelling – a 3D printing technique – to manufacture continuous carbon fibre-reinforced thermoplastics. Several parameters including number of reinforced layers, material impact and interlayer gap have been investigated and optimized using response surface method. Successful incorporation of modified novel nozzle design in a dual nozzle setup resulted in the realization of controlled manufacturing of continuously reinforced composites leading to reinforced yet smooth surface finished samples. Several samples were made, and mechanical testing, parameter optimization, strength calculations and fracture analysis were carried out. For polylactic acid (PLA), tensile strength of 112 MPa and flexural strength of 164 MPA were achieved – an almost 3 ti...
Polymers
An improved simulation-based thermoforming design process based on the integration of material characterization and as-formed structural analysis is proposed. The tendency of thermoplastic composites to wrinkle during forming has made simulation critical to optimized manufacturing, but the material models required are complex and time consuming to create. A suite of experimental methods has been developed for measurement of several required properties of the molten thermoplastic composite. These methods have the potential to enhance thermoplastic composites manufacturing by simplifying and expediting the process. These material properties have been verified by application to thermomechanical forming predictions using commercial simulation software. The forming predictions showed improved agreement with experimental results compared to those using representative material properties. A tool for using thermoforming simulations to inform more accurate structural models has been tested o...
Since the first FRP material applications emerged in the fifties, various industrial markets (from aerospace to consumer goods) have adopted FRP composites due to their attractive inherent mix of properties: FRP composites represent low density with elevated mechanical performance and display better environmental resistance than traditional materials such as steel and aluminium. As FRP composites gradually became more used in structural design, early manufacturing processes changed, were optimized and became partly automated. The evolution in manufacturing processes was indeed necessary to keep pace with the increasing complexity of geometrical designs, more demanding mechanical requirements, more stringent environmental regulations and ever stronger market pressures concerning cost and production volume. This paper aims to present a review of manufacturing processes for fibre reinforced thermoset polymer (FRP) applications through one of the most common products for the industrial environment: storage pressure tanks, vessels and silos.