Ductile woven silk fibre thermoplastic composites with quasi-isotropic strength

Thermoplastic composites (TPCs) are promising materials for aerospace, transportation, shipbuilding, and civil use owing to their lightweight, rapid prototyping, reprocessing, and environmental recycling advantages. The connection assemblies of TPCs components are crucial to their application; compared with traditional mechanical joints and adhesive connections, fusion connections are more promising, particularly resistance welding. This study aims to investigate the effects of process control parameters, including welding current, time, and pressure, for optimization of resistance welding based on glass fiber-reinforced polypropylene (GF/PP) TPCs and a stainless-steel mesh heating element. A self-designed resistance-welding equipment suitable for the resistance welding process of GF/PP TPCs was manufactured. GF/PP laminates are fabricated using a hot press, and their mechanical properties were evaluated. The resistance distribution of the heating elements was assessed to conform with a normal distribution. Tensile shear experiments were designed and conducted using the Taguchi method to evaluate and predict process factor effects on the lap shear strength (LSS) of GF/PP based on signal-to-noise ratio (S/N) and analysis of variance. The results show that current is the main factor affecting resistance welding quality. The optimal process parameters are a current of 12.5 A, pressure of 2.5 MPa, and time of 540 s. The experimental LSS under the optimized parameters is 12.186 MPa, which has a 6.76% error compared with the result predicted based on the S/N.

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Additive Manufacturing-Based In Situ Consolidation of Continuous Carbon Fibre-Reinforced Polycarbonate

Materials ◽

10.3390/ma14092450 ◽

2021 ◽

Vol 14 (9) ◽

pp. 2450

Author(s):

Andreas Borowski ◽

Christian Vogel ◽

Thomas Behnisch ◽

Vinzenz Geske ◽

Maik Gude ◽

...

Keyword(s):

Additive Manufacturing ◽

Carbon Fibre ◽

Bending Test ◽

Thermoplastic Composites ◽

Experimental Investigations ◽

Material Structure ◽

Three Point Bending ◽

Continuous Fibre ◽

Local Material

Continuous carbon fibre-reinforced thermoplastic composites have convincing anisotropic properties, which can be used to strengthen structural components in a local, variable and efficient way. In this study, an additive manufacturing (AM) process is introduced to fabricate in situ consolidated continuous fibre-reinforced polycarbonate. Specimens with three different nozzle temperatures were in situ consolidated and tested in a three-point bending test. Computed tomography (CT) is used for a detailed analysis of the local material structure and resulting material porosity, thus the results can be put into context with process parameters. In addition, a highly curved test structure was fabricated that demonstrates the limits of the process and dependent fibre strand folding behaviours. These experimental investigations present the potential and the challenges of additive manufacturing-based in situ consolidated continuous fibre-reinforced polycarbonate.

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Abrasion wear behavior of glass–basalt hybrid thermoplastic composites under the influence of abrading load and velocity: Multipass effect

10.1063/5.0022603 ◽

2020 ◽

Author(s):

B. M. Rudresh ◽

B. N. Ravikumar ◽

D. Madhu

Keyword(s):

Wear Behavior ◽

Thermoplastic Composites ◽

Abrasion Wear

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Adhesion Studies during Generative Hybridization of Textile-Reinforced Thermoplastic Composites via Additive Manufacturing

Materials ◽

10.3390/ma14143888 ◽

2021 ◽

Vol 14 (14) ◽

pp. 3888

Author(s):

Johanna Maier ◽

Christian Vogel ◽

Tobias Lebelt ◽

Vinzenz Geske ◽

Thomas Behnisch ◽

...

Keyword(s):

Additive Manufacturing ◽

Polyamide 6 ◽

Thermoplastic Composites ◽

Efficient Production ◽

Angle Measurements ◽

Small Series ◽

Contact Angle Measurements ◽

Static Tensile ◽

Pre Treatment ◽

Manufacturing Technologies

Generative hybridization enables the efficient production of lightweight structures by combining classic manufacturing processes with additive manufacturing technologies. This type of functionalization process allows components with high geometric complexity and high mechanical properties to be produced efficiently in small series without the need for additional molds. In this study, hybrid specimens were generated by additively depositing PA6 (polyamide 6) via fused layer modeling (FLM) onto continuous woven fiber GF/PA6 (glass fiber/polyamide 6) flat preforms. Specifically, the effects of surface pre-treatment and process-induced surface interactions were investigated using optical microscopy for contact angle measurements as well as laser profilometry and thermal analytics. The bonding characteristic at the interface was evaluated via quasi-static tensile pull-off tests. Results indicate that both the bond strength and corresponding failure type vary with pre-treatment settings and process parameters during generative hybridization. It is shown that both the base substrate temperature and the FLM nozzle distance have a significant influence on the adhesive tensile strength. In particular, it can be seen that surface activation by plasma can significantly improve the specific adhesion in generative hybridization.

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Thermoplastic Pultrusion: A Review

Polymers ◽

10.3390/polym13020180 ◽

2021 ◽

Vol 13 (2) ◽

pp. 180

Author(s):

Kirill Minchenkov ◽

Alexander Vedernikov ◽

Alexander Safonov ◽

Iskander Akhatov

Keyword(s):

Composite Structures ◽

Raw Materials ◽

Thermoplastic Composites ◽

Future Research ◽

Transportation Industry ◽

Architectural Engineering ◽

Simulation Techniques ◽

New Perspective ◽

The Many ◽

Lower Production

Pultrusion is one of the most efficient methods of producing polymer composite structures with a constant cross-section. Pultruded profiles are widely used in bridge construction, transportation industry, energy sector, and civil and architectural engineering. However, in spite of the many advantages thermoplastic composites have over the thermoset ones, the thermoplastic pultrusion market demonstrates significantly lower production volumes as compared to those of the thermoset one. Examining the thermoplastic pultrusion processes, raw materials, mechanical properties of thermoplastic composites, process simulation techniques, patents, and applications of thermoplastic pultrusion, this overview aims to analyze the existing gap between thermoset and thermoplastic pultrusions in order to promote the development of the latter one. Therefore, observing thermoplastic pultrusion from a new perspective, we intend to identify current shortcomings and issues, and to propose future research and application directions.

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Effects of Water and Chemical Solutions Ageing on the Physical, Mechanical, Thermal and Flammability Properties of Natural Fibre-Reinforced Thermoplastic Composites

Molecules ◽

10.3390/molecules26154581 ◽

2021 ◽

Vol 26 (15) ◽

pp. 4581

Author(s):

Baljinder K. Kandola ◽

S. Ilker Mistik ◽

Wiwat Pornwannachai ◽

A. Richard Horrocks

Keyword(s):

Salt Water ◽

Flexural Modulus ◽

Moisture Sorption ◽

Natural Fibre ◽

Thermoplastic Composites ◽

Wool Fibre ◽

Poly Lactic Acid ◽

Natural Polymers ◽

Chemical Solutions ◽

Pp Composites

Biocomposites comprising a combination of natural fibres and bio-based polymers are good alternatives to those produced from synthetic components in terms of sustainability and environmental issues. However, it is well known that water or aqueous chemical solutions affect natural polymers/fibres more than the respective synthetic components. In this study the effects of water, salt water, acidic and alkali solutions ageing on water uptake, mechanical properties and flammability of natural fibre-reinforced polypropylene (PP) and poly(lactic acid) (PLA) composites were compared. Jute, sisal and wool fibre- reinforced PP and PLA composites were prepared using a novel, patented nonwoven technology followed by the hot press method. The prepared composites were aged in water and chemical solutions for up to 3 week periods. Water absorption, flexural properties and the thermal and flammability performances of the composites were investigated before and after ageing each process. The effect of post-ageing drying on the retention of mechanical and flammability properties has also been studied. A linear relationship between irreversible flexural modulus reduction and water adsorption/desorption was observed. The aqueous chemical solutions caused further but minor effects in terms of moisture sorption and flexural modulus changes. PLA composites were affected more than the respective PP composites, because of their hydrolytic sensitivity. From thermal analytical results, these changes in PP composites could be attributed to ageing effects on fibres, whereas in PLA composite changes related to both those of fibres present and of the polymer. Ageing however, had no adverse effect on the flammability of the composites.

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