Journal of Reinforced Plastics and Composites

The sizes effects on the strengths of open-hole fibre-reinforced composite laminates subjected to tensile loading (OHT) have been investigated widely. However, little attention has been paid to the influence of material orthotropy. This paper presents a progressive damage model for the model failure of notched laminates under tensile loading based on continuum damage mechanics and cohesive elements. The effects of orthotropy on the failure of notched laminates with seven different ply sequences are investigated by our proposed model. The prediction results adopting the Hoffman and Pinho failure criterions to determine matrix damage initiation are compared with the results of experiments. Our proposed models are able to predict the strong influence of orthotropy on strengths of open-hole laminate under tension, and model using Pinho criterion can predict the open-hole tension strength most accurately.

Polymer matrix composite tanks offer major advantages to the transport industry in terms of increased payload and corrosion resistance compared to conventional steel tanks. Chemical resistance and versatility can be enhanced through the addition of a thermoplastic liner. This paper presents the results of chemical conditioning, testing and analysis of a linear low-density polyethylene liner, on its own and supported by carbon fiber reinforced polymer. Results are compared to ADR (European Agreement Concerning the International Carriage of Dangerous Goods by Road) requirements. The linear low-density polyethylene liner was tested in combination with 12–15% sodium hypochlorite and 98% sulphuric acid. The results indicate that the liner is suitable for service in tanks transporting these two chemicals. Liners were conditioned at 50℃ for periods of 1000 or 2000 h. Shore D hardness tests and three-point bend tests were performed, compared to unconditioned benchmarks, and found to pass ADR requirements. Finite element models were validated and used to facilitate understanding of the failure of the laminates. Predictions indicate that failure load increases with increased liner modulus, yield stress, and thickness. The models also indicate that the laminate strength and modulus is not significantly changed during chemical conditioning for the stated chemicals.

Nesting and compression processes of plain woven fabrics are the most important features in the composites manufacture of fiber-reinforced composite components, while their relationships are still not reported. Here, in this work, we clearly reveal nesting and compression characteristics of typical fabrics through systematical compression experiments. We present the theoretical expression of the nesting effects on the initial thickness h and experimentally demonstrate its effectiveness. We find that nesting decreases the h and the minimum h appears in the maximum nesting condition. Meanwhile, we experimentally demonstrate that for plain woven fabrics, nesting has relationships with the thickness in compression t, while it has no effects on the thickness deformation Δ in the whole compression processes. Thus, we reveal the relationships between the nesting and h, t, Δ in the compression processes. Moreover, the applicability of these results for other types of fiber is also illustrated by comprehensive analysis. These obtained results provide the references for thickness evolution rules, volume fraction, and molding process of the fiber-reinforced composite components.

The development and recent applications of reinforced thermoplastic pipes for offshore oil and gas applications are reviewed. The design and materials of reinforced thermoplastic pipes are presented. Reinforced thermoplastic pipes have been increasingly accepted as an important alternative to traditional metallic offshore pipes due to their distinct advantages such as a higher stiffness to weight ratio, improved fatigue resistance and better corrosion resistance. Their potential applications can be extended to deep-water risers. Loading conditions which could be experienced by them for offshore applications are described. Existent studies and analyses of offshore pipes under these loading conditions are discussed. Based on this discussion, this article outlines the limitations of the current studies of reinforced thermoplastic pipes and future work to improve the analysis and design of reinforced thermoplastic pipes is recommended.

A series of experiments on 3D angle-interlock carbon/epoxy woven composites were carried out using the split Hopkinson pressure bar and split Hopkinson tension bar. These tests were accomplished to investigate the strain rate effect of the dynamic compressive and tensile properties. The strain rate range is about 500/s to 1500/s for through-thickness compressive tests, 150/s to 600/s for in-plane compressive tests, and 600/s to 1000/s for in-plane tensile tests. The corresponding quasi-static properties are given for reference. The tested specimens were observed using optical microscope and scanning electron microscope. The main failure modes of the specimens include fiber breakage, fiber pull out and matrix crack. The compressive modulus of through-thickness direction is positively related to the strain rate. The compressive strength and modulus of in-plane direction shows a light fluctuation within the studied strain rate. It is found that the tensile strength and modulus of in-plane direction are negatively related to the strain rate.