Viscoelastic response of unidirectionally reinforced thermoplastic composites to off axis deformation

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.

Download Full-text

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.

Download Full-text

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

Download Full-text

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.

Download Full-text