scholarly journals Characterization and Numerical Modelling of Through-Thickness Metallic-Pin-Reinforced Fibre/Thermoplastic Composites under Bending Loading

2020 ◽  
Vol 4 (4) ◽  
pp. 188
Author(s):  
Holger Böhm ◽  
Hailun Zhang ◽  
Benjamin Gröger ◽  
Andreas Hornig ◽  
Maik Gude
Keyword(s):  
Mechanical Properties ◽  
Numerical Modelling ◽  
Matrix Cracking ◽  
Thermoplastic Composites ◽  
Continuum Damage Mechanic ◽  
Damage Mechanic ◽  
Hybrid Yarn ◽  
Cohesive Zone Modelling ◽  
Delamination Resistance ◽  
Plane Direction

Through-Thickness Reinforcement (TTR) technologies are well suited to improving the mechanical properties in the out-of-plane direction of fibre-reinforced composites. However, besides the enhancement of delamination resistance and thus the prevention of overall catastrophic failure, the presence of additional reinforcement elements in the composite structure affects also the mechanical properties in in-plane direction. In this work, the flexural behaviour of a glass-polypropylene (GF/PP) hybrid yarn-based composite with TTR in form of metallic pins has been investigated experimentally and numerically. The insertion of the metallic pins is realized via thermoactivated pinning technology (TAP). In four-point-bending tests, it is shown that the flexural stiffness and strength decreases with an increase of the overall pin density. Hereby, it is observed that the pins act as crack initiators. For numerical modelling on specimen level, a continuum damage mechanic (CDM) model is used to predict the nonlinear deformation response of the composite, as well as fibre fracture and matrix cracking. A debonding and slipping phenomena of the pin in the composite is modelled by a cohesive zone modelling approach for the interface between pin and composite.

Impacts of thermoplastics content on mechanical properties of continuous fiber-reinforced thermoplastic composites

2021 ◽  
Vol 216 ◽  
pp. 108859
Author(s):  
Dong-Jun Kwon ◽  
Neul-Sae-Rom Kim ◽  
Yeong-Jin Jang ◽  
Hyun Ho Choi ◽  
Kihyun Kim ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermoplastic Composites ◽  
Fiber Reinforced ◽  
Continuous Fiber

Progressive Failure Analysis of Thermoplastic PE/PE Composites: Labeling of Clustered AE Signals

2013 ◽  
Vol 821-822 ◽  
pp. 1479-1483
Author(s):  
Bi Ling Yang ◽  
Sen Liu ◽  
Xiao Xia He ◽  
Shao Qiong Zheng
Keyword(s):  
Failure Analysis ◽  
Progressive Failure ◽  
Tensile Load ◽  
Matrix Cracking ◽  
Thermoplastic Composites ◽  
Damage Mechanisms ◽  
Progressive Failure Analysis ◽  
Fast Fourier Transform Analysis ◽  
Static Tensile ◽  
Ae Signals

Thermoplastic self-reinforced polyethylene (PE/PE) composites were tested under quasi-static tensile load and the failure processes weremonitored by Acoustic Emission (AE) technique. The AE signals were collected and clustered by Unsupervised Pattern Recognition (UPR) scheme. The initiation and progression of the damage mechanisms in the composites can then be reviewed by the cumulative AE hits of each cluster versus strain curves. But the labeling of each cluster is crucial to the failure analysis. The paper focuses on this correlating between the obtained clusters and their specific damage modes. This was carried out by waveform visualization and Fast Fourier Transform analysis. Pure resin and fiber bundles were tested to assist in the labeling of signal classes in the composites (90°, 0° and [±45°] specimens). Typical waveforms of matrix cracking, fiber-matrix debonding, fiber fracture and fiber pullout were indentified respectively. The evolution process of various damage mechanisms in the composites revealed that the correlating method was effective. An objective and repeatable analytical procedure is established for the investigation of progressive failure mechanisms in the thermoplastic composites.

Mechanical Properties of Thermoplastic Composites via In Situ Polymerization from Cyclic Oligomers

2013 ◽  
Vol 750-752 ◽  
pp. 7-10
Author(s):  
Kou An Hao ◽  
Zhen Qing Wang ◽  
Li Min Zhou
Keyword(s):  
Mechanical Properties ◽  
In Situ Polymerization ◽  
High Viscosity ◽  
Thermoplastic Composites ◽  
Thermoplastic Matrix ◽  
Polymerization Catalyst ◽  
Short Beam ◽  
Beam Shear ◽  
Cyclic Oligomers

Fiber impregnation has been the main obstacle for thermoplastic matrix with high viscosity. This problem could be surmounted by adapting low viscous polymeric precursors Woven basalt fabric reinforced poly (butylenes terephthalate) composites were produced via in-situ polymerization at T=210°C. Before polymerization, catalyst was introduced to the reinforcement surface with different concentration. DSC is used to determine the polymerization and crystallization. SEM is used to detect whether the catalyst existed on surface. Both flexural and short-beam shear test are employed to study the corresponding mechanical properties.

scholarly journals Moisture Absorption Effects on the Mechanical Properties of Sandwich Biocomposites with Cork Core and Flax/PLA Face Sheets

Molecules ◽  
2021 ◽  
Vol 26 (23) ◽  
pp. 7295
Author(s):  
Hom Nath Dhakal ◽  
Chulin Jiang ◽  
Moumita Sit ◽  
Zhongyi Zhang ◽  
Moussa Khalfallah ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Failure Modes ◽  
Moisture Absorption ◽  
Mechanical Performance ◽  
Core Sample ◽  
Environmental Benefits ◽  
Matrix Cracking ◽  
Core Material ◽  
Poly Lactic Acid ◽  
The Core

The aim of this study was to evaluate the moisture absorption behaviour and its influence on the mechanical properties of newly developed sandwich biocomposites with flax fibre-reinforced poly-lactic acid (PLA) face sheets and soft cork as the core material. Three different types of sandwich biocomposite laminates comprised of different layup configurations, namely, non-woven flax/PLA (Sample A), non-woven flax/PLA and cork as core (Sample B) and non-woven flax/paper backing/PLA, cork as core (Sample C), were fabricated. In order to evaluate the influence of moisture ingress on the mechanical properties, the biocomposites were immersed in seawater for a period of 1200 h. The biocomposites (both dry and water immersed) were then subjected to tensile, flexural and low-velocity falling weight impact tests. It was observed from the experimental results that the moisture uptake significantly influenced the mechanical properties of the biocomposites. The presence of the cork and paper in sample C made it more susceptible to water absorption, reaching a value of 34.33%. The presence of cork in the core also has a considerable effect on the mechanical, as well as energy dissipation, behaviours. The results of sample A exhibited improved mechanical performance in both dry and wet conditions compared to samples B and C. Sample A exhibits 32.6% more tensile strength and 81.4% more flexural strength in dry conditions than that in sample C. The scanning electron microscopy (SEM) and X-ray micro-CT images revealed that the failure modes observed are a combination of matrix cracking, core crushing and face core debonding. The results from this study suggest that flax/PLA sandwich biocomposites can be used in various lightweight applications with improved environmental benefits.

scholarly journals Mechanical Properties of Compression Moulded Aggregate-Reinforced Thermoplastic Composite Scrap

2021 ◽  
Vol 5 (11) ◽  
pp. 299
Author(s):  
Julien Moothoo ◽  
Mahadev Bar ◽  
Pierre Ouagne
Keyword(s):  
Mechanical Properties ◽  
Tensile Properties ◽  
Test Method ◽  
Thermoplastic Composite ◽  
Recycled Aggregate ◽  
Thermoplastic Composites ◽  
Mechanical Recycling ◽  
Compression Moulding ◽  
Grain Sizes ◽  
Recycled Composites

Recycling of thermoplastic composites has drawn a considerable attention in the recent years. However, the main issue with recycled composites is their inferior mechanical properties compared to the virgin ones. In this present study, an alternative route to the traditional mechanical recycling technique of thermoplastic composites has been investigated with the view to increase mechanical properties of the recycled parts. In this regard, the glass/polypropylene laminate offcuts are cut in different grain sizes and processed in bulk form, using compression moulding. Further, the effect of different grain sizes (i.e., different lengths, widths and thicknesses) and other process-related parameters (such as mould coverage) on the tensile properties of recycled aggregate-reinforced composites have been investigated. The tensile properties of all composite samples are tested according to ISO 527-4 test method and the significance of test results is evaluated according to Student’s t-test and Fisher’s F-test respectively. It is observed that the tensile moduli of the recycled panels are close to the equivalent quasi-isotropic continuous fibre-reinforced reference laminate while there is a noteworthy difference in the strengths of the recycled composites. At this stage, the manufactured recycled composites show potential for stiffness-driven application.

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