Investigation on Shear Strength of Steel-Polymer Interface in Plastic Pipe Reinforced by Cross Helically Wound Steel Wires

Shear strength of fibre-matrix adhesive interface is crucial important to the mechanical performance of fibre-reinforced plastic pipes and fittings, due to its function for load transfer between the fibre and the matrix. In this study, pull-out tests of steel-polymer specimens were carried out with different embedded lengths. Ultrasonic scanning was adopted to monitor the failure procedure of the interface. From the analysis of UT scanning graphs, it could be determined that the studied steel-polymer interface failed rapidly on the whole embedded length under the maximal pull-out force, but not in the manner that crack initiated from a stress concentration point under a relatively small pull-out force and then propagated gradually. Different kinds of pull-out analytical models were discussed. Finally the analytical model of yielding interface was applied to characterize the steel-polymer interfacial adhesive property. Combing with experimental results of pull-out tests of different embedded lengths, the nominal bond shear strength was calculated out.

Thermo-Mechanical Properties of PLA/Short Flax Fiber Biocomposites

Applied Sciences ◽

10.3390/app9183797 ◽

2019 ◽

Vol 9 (18) ◽

pp. 3797 ◽

Cited By ~ 10

Author(s):

Laura Aliotta ◽

Vito Gigante ◽

Maria-Beatrice Coltelli ◽

Patrizia Cinelli ◽

Andrea Lazzeri ◽

...

Keyword(s):

Mechanical Properties ◽

Elastic Modulus ◽

Load Transfer ◽

Mechanical Performance ◽

Nucleating Agent ◽

Flax Fiber ◽

Analytical Models ◽

Poly Lactic Acid ◽

Flax Fibers ◽

In this work, biocomposites based on poly(lactic acid) (PLA) and short flax fibers (10–40 wt.%) were produced by extrusion and characterized in terms of thermal, mechanical, morphological, and thermo-mechanical properties. Analytical models were adopted to predict the tensile properties (stress at break and elastic modulus) of the composites, and to assess the matrix/fiber interface adhesion. The resulting composites were easily processable by extrusion and injection molding up to 40 wt.% of flax fibers. It was observed that despite any superficial treatment of fibers, the matrix/fiber adhesion was found to be sufficiently strong to ensure an efficient load transfer between the two components obtaining composites with good mechanical properties. The best mechanical performance, in terms of break stress (66 MPa), was obtained with 20 wt.% of flax fibers. The flax fiber acted also as nucleating agent for PLA, leading to an increment of the composite stiffness and, at 40 wt.% of flax fibers, improving the elastic modulus decay near the PLA glass transition temperature.

Design of composite lattice materials combined with fabrication approaches

Journal of Composite Materials ◽

10.1177/0021998318785710 ◽

2018 ◽

Vol 53 (3) ◽

pp. 393-404 ◽

Cited By ~ 9

Author(s):

Jun Xu ◽

Yaobo Wu ◽

Xiang Gao ◽

Huaping Wu ◽

Steven Nutt ◽

...

Keyword(s):

Shear Strength ◽

Mechanical Performance ◽

Analytical Models ◽

Core Material ◽

Foam Core ◽

Hierarchical Lattice ◽

Bottom Up ◽

Lattice Materials ◽

Assembly Technique ◽

Composite Lattice

Lattice materials can be designed through their microstructure while concurrently considering fabrication feasibility. Here, we propose two types of composite lattice materials with enhanced resistance to buckling: (a) hollow lattice materials fabricated by a newly developed bottom-up assembly technique and the previously developed thermal expansion molding technique and (b) hierarchical lattice materials with foam core sandwich trusses fabricated by interlocking assembly process. The mechanical performance of sandwich structures featuring the two types of lattice cores was tested and analyzed theoretically. For hollow lattice core material, samples from two different fabrication processes were compared and both failed by nodal rupture or debonding. In contrast, hierarchical lattice structures failed by shear buckling without interfacial failure in the sandwich struts. Calculations using established analytical models indicated that the shear strength of hollow lattice cores could be optimized by judicious selection of the thickness of patterned plates. Likewise, the shear strength of hierarchical foam core truss cores could be maximized (with minimal weight) through design of truss geometry. The bottom-up assembly technique could provide a feasible way for mass production of lattice cores, but the design about how to assembly is critical. Hierarchical lattice cores with foam sandwich trusses should be a suitable choice for future lightweight material application.

Interfaces in Fibre Reinforced Cements

MRS Proceedings ◽

10.1557/proc-114-133 ◽

1987 ◽

Vol 114 ◽

Cited By ~ 3

Author(s):

A. Bentur

Keyword(s):

Mechanical Performance ◽

Fibre Surface ◽

Special Structure ◽

Analytical Models ◽

ABSTRACTThe microstructure of the matrix in the vicinity of the fibre surface is quite different from the microstructure of the bulk paste matrix. This can have an important effect on the processes that take place at the interface, such as crack-fibre interaction and debonding. The present paper describes the special structure of this zone, in monofilament and bundled fibre reinforced cements, and discusses its effects on some characteristics of the mechanical performance of the composites, which cannot be predicted by analytical models assuming a uniform matrix up to the fibre surface. The modification of the microstructure at the interface as a means for improving properties in some composites is described.

Pull-out method for direct measuring the interfacial shear strength between short plant fibers and thermoplastic polymer composites (TPC)

Holzforschung ◽

10.1515/hf-2013-0052 ◽

2014 ◽

Vol 68 (1) ◽

pp. 17-21 ◽

Cited By ~ 2

Author(s):

Hao Wang ◽

Genlin Tian ◽

Hankun Wang ◽

Wanju Li ◽

Yan Yu

Keyword(s):

Shear Strength ◽

Polymer Composites ◽

Interfacial Shear Strength ◽

Interfacial Shear ◽

Thermoplastic Polymer ◽

Plant Fibers ◽

Important Indicator ◽

Pull Out ◽

Research Activities ◽

Abstract Thermoplastic polymer composites reinforced with short plant fiber are worldwide in focus of research activities. Interfacial shear strength (IFSS) is an important indicator for evaluating the bonding quality between the fiber and the matrix polymer. However, the direct measurement of IFSS is especially difficult in the case of short fibers. In the present article, a method is proposed to this purpose, which is related to the known “fiber pulling out” methodology. In the case of single bamboo fibers, the IFSS in a polypropylene (PP) matrix was on, an average, of 5 MPa, which can be considered as weak. Scanning electron microscopy images revealed a rough inner surface in PP cavities left after fiber pulling out. This is direct evidence that a mechanical interlocking mechanism is active in the interphase between the hydrophilic fibers and the hydrophobic matrix.

Volume 1: Development and Characterization of Multifunctional Materials; Modeling, Simulation, and Control of Adaptive Systems; Integrated System Design and Implementation ◽

Magnetic-Assisted Alignment of Reinforcing Functionalized-Fibers in a Composite for Lightweight Structures

10.1115/smasis2018-7911 ◽

2018 ◽

Author(s):

C. Torres-Sánchez ◽

M. Haghihi-Abayneh ◽

P. P. Conway

Keyword(s):

Load Transfer ◽

Mechanical Performance ◽

Active Form ◽

Lightweight Structures ◽

Physico Chemical ◽

The Matrix ◽

After Effect ◽

Reduction Of Co2 ◽

Magnetically Aligned

Localized reinforcement of composites employed to manufacture parts for the transport industries is making possible the lightweighting of components that have a much sought-after effect in the reduction of CO2 and NOx emissions. However, its realization, through the removing of mass where it is not required and reinforcement added to areas more prone to stress from working loads, relies on the development of novel manufacturing processes that can create structures whose performance is on a par with their solid counterparts, but at a fraction of the weight and at an affordable production cost. In this work we exploit the use of a very weak and safe magnetic field to control the location and orientation of functionalized discontinuous carbon fibers within a polymeric structural (polyurethane) foam to create performance-optimized composites. Two wet-chemistry methods (i.e. in-situ precipitation-deposition and amine-co-adjuvated electrodeposition of magnetite) to transform commercial carbon fiber into a magnetically active form were explored. The resulting fibers were analyzed and characterized through a set of physico-chemical tests. The functionalized fibers were then embedded at 3 different %vol contents in the polymeric matrix at given locations and with a desired alignment. Their mechanical performance (incl. compression, tension) was assessed and benchmarked against both a similar %volumetric content but non-functionalized-reinforcement (i.e. randomly distributed) composites and to non-reinforced matrices. In the two sets of reinforced composites (random and aligned) there is a positive correlation between stiffness, yield strength and strain with increasing %vol content. Both sets outperformed the non-reinforced matrix, demonstrating good fiber adhesion within the matrix and successful load transfer from matrix to fiber. The magnetically aligned composites generally outperformed the non-functionalized ones in terms of stiffness and strength at yield.

Influence of Unsizing and Carbon Nanotube Grafting of Carbon Fibre on Fibre Matrix Interfacial Shear Strength of Carbon Fibre and Polyamide 6

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.827.178 ◽

2019 ◽

Vol 827 ◽

pp. 178-183

Author(s):

Kazuto Tanaka ◽

Kanako Yamada ◽

Yoshitake Hinoue ◽

Tsutao Katayama

Keyword(s):

Shear Strength ◽

Carbon Fibre ◽

Interfacial Shear Strength ◽

Chemical Vapour ◽

Polyamide 6 ◽

Interfacial Shear ◽

Morphological Observation ◽

Production Cycle ◽

Pull Out ◽

Carbon Fibre Reinforced Thermoplastics (CFRTP) are expected to be applied to the automotive industry instead of CFRP which require curing time, due to the expected short production cycle time of CFRTP, which is using thermoplastic as a matrix. We reported that the grafting of carbon nanotubes (CNTs) on the carbon fibre improves the fibre matrix interfacial shear strength. In our process to graft CNTs on carbon fibre, chemical vapour deposition (CVD) method was used and Ni, which was used as the catalyst, was electrically plated onto carbon fibres. Since commercially available carbon fibre was sized, which may affect the plating behaviour of Ni, the effects of sizing agents on CNT deposition have to be clarified. In this study, Ni for catalytic metal was plated by electrolytic plating using a watt bath on spread PAN-based carbon fibre and unsized carbon fibre, and the influence of the sizing agent to the distribution of Ni was evaluated. The morphological observation of carbon fibre and single fibre pull-out test were conducted to clarify the influence of sizing agent on the CNT deposition and the interfacial shear strength between the CNT grafted carbon fibre and Polyamide 6 (PA6). Uniform distribution of small sized Ni particles can be obtained on unsized carbon fibre and uniform Ni particles results in uniform CNT distribution. The CNT grafted unsized carbon fibre showed higher interfacial shear strength with PA6 than that of sized carbon fibre.

Interfacial phenomena in the fracture resistance of interfaces

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100105667 ◽

1988 ◽

Vol 46 ◽

pp. 720-721

Author(s):

A. G. Evans

Keyword(s):

Fracture Resistance ◽

Mechanical Response ◽

Mechanical Performance ◽

Friction Stress ◽

Matrix Composites ◽

Low Friction ◽

Fiber Failure ◽

Pull Out ◽

Brittle Matrix Composites ◽

In composite systems, the mechanical response of interfaces to the approach of cracks that initially form either in the matrix or in the fiber dominates the mechanical performance. In particular, in brittle matrix composites, the interface must have a sufficiently low fracture resistance compared with that of both the fiber and matrix that the crack diverts into the interface and debonds the fiber, Thereafter, the debonded fiber must be able to slide against the matrix with a low friction stress in order to inhibit fiber failure and thus enhance pull-out. These processes are schematically illustrated in Fig. 1. Mechanics investigations have established requirements concerning debonding and sliding that must be satisfied in order to achieve good composite properties. At the simplest level, these studies reveal that the fracture energy of the interface should be less than about one-third that of either the fiber or the matrix.

Effects of Temperature on the Fibre Matrix Interfacial Shear Strength of Carbon Nanotube Grafted Carbon Fibre Reinforced Heat Resistant Resin

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.827.488 ◽

2019 ◽

Vol 827 ◽

pp. 488-492

Author(s):

Kazuto Tanaka ◽

Daiki Kugimoto ◽

Tsutao Katayama

Keyword(s):

Mechanical Properties ◽

Shear Strength ◽

Carbon Fibre ◽

Interfacial Shear Strength ◽

Interfacial Shear ◽

Pull Out ◽

Significant Difference ◽

Effects Of Temperature ◽

Structural Parts ◽

Transportation sector is required to reduce CO2 emissions as environmental problems are becoming more serious. Carbon fibre reinforced thermoplastic (CFRTP) are expected to be applied to the structural parts of automobiles and aircrafts because of their superior mechanical properties such as high specific strength, high specific stiffness and high recyclability. One of the problems in using CFRTP for the structural parts is heat resistance, and it is necessary to clarify the mechanical properties under their service environmental temperature. The tensile strength of CFRTP at high temperatures decreases with temperature rise. The fibre matrix interfacial shear strength is reported to be improved by grafting of carbon nanotubes (CNTs) on the surface of carbon fibre. In this study, in order to clarify the effects of temperature on the fibre matrix interfacial shear strength of CNTs grafted carbon fibre reinforced PPS resin, single fibre pull-out test was conducted. While the interfacial shear strength of CNT grafted-CF/PPS is higher than that of As-received-CF/PPS at 25 °C, no significant difference was found in the interfacial shear strength of As-received-CF/PPS and CNT grafted-CF/PPS at 80 °C.

Development of Bio-Inspired Hierarchical Fibres to Tailor the Fibre/Matrix Interphase in (Bio)Composites

Polymers ◽

10.3390/polym13050804 ◽

2021 ◽

Vol 13 (5) ◽

pp. 804

Author(s):

Estelle Doineau ◽

Bernard Cathala ◽

Jean-Charles Benezet ◽

Julien Bras ◽

Nicolas Le Le Moigne

Keyword(s):

High Performance ◽

Load Transfer ◽

Hierarchical Structures ◽

High Strength ◽

The Matrix ◽

High Performance Composite ◽

Hierarchical Architectures ◽

Mechanical Performances ◽

Several naturally occurring biological systems, such as bones, nacre or wood, display hierarchical architectures with a central role of the nanostructuration that allows reaching amazing properties such as high strength and toughness. Developing such architectures in man-made materials is highly challenging, and recent research relies on this concept of hierarchical structures to design high-performance composite materials. This review deals more specifically with the development of hierarchical fibres by the deposition of nano-objects at their surface to tailor the fibre/matrix interphase in (bio)composites. Fully synthetic hierarchical fibre reinforced composites are described, and the potential of hierarchical fibres is discussed for the development of sustainable biocomposite materials with enhanced structural performance. Based on various surface, microstructural and mechanical characterizations, this review highlights that nano-objects coated on natural fibres (carbon nanotubes, ZnO nanowires, nanocelluloses) can improve the load transfer and interfacial adhesion between the matrix and the fibres, and the resulting mechanical performances of biocomposites. Indeed, the surface topography of the fibres is modified with higher roughness and specific surface area, implying increased mechanical interlocking with the matrix. As a result, the interfacial shear strength (IFSS) between fibres and polymer matrices is enhanced, and failure mechanisms can be modified with a crack propagation occurring through a zig-zag path along interphases.