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The wear profile analysis, obtained by different tribometers, is essential to characterise the wear mechanisms. However, most of the available methods did not take the stress distribution over the wear profile in consideration, which causes inaccurate analysis. In this study, the wear profile of polymer–metal contact, obtained by block-on-ring configuration under dry sliding conditions, was analysed using finite element modelling (FEM) and experimental investigation. Archard's wear equation was integrated into a developed FORTRAN–UMESHMOTION code linked with Abaqus software. A varying wear coefficient (k) values covering both running-in and steady state regions, and a range of applied loads involving both mild and severe wear regions were measured and implemented in the FEM. The FEM was in good agreement with the experiments. The model reproduced the stress distribution profiles under variable testing conditions, while their values were affected by the sliding direction and maximum wear depth (hmax). The largest area of the wear profile, exposed to the average contact stresses, is defined as the normal zone. Whereas the critical zones were characterized by high stress concentrations reaching up to 10 times of that at the normal zone. The wear profile was mapped to identify the critical zone where the stress concentration is the key point in this definition. The surface features were examined in different regions using scanning electron microscope (SEM). Ultimately, SEM analysis showed severer damage features in the critical zone than that in the normal zone as proven by FEM. However, the literature data presented and considered the wear features the same at any point of the wear profile. In this study, the normal zone was determined at a stress value of about 0.5 MPa, whereas the critical zone was at about 5.5 MPa. The wear behaviour of these two zones showed totally different features from one another. [ABSTRACT FROM AUTHOR]

Hollow box pultruded fibre-reinforced polymers (PFRP) profiles are increasingly used as structural elements in many structural applications due to their cost-effective manufacturing process, excellent mechanical properties-to-weight ratios, and superior corrosion resistance. Despite the extensive usage of PFRP profiles, there is still a lack of knowledge in the design for manufacturing against local buckling on the structural level. In this review, the local buckling of open-section (I, C, Z, L, T shapes) and closed-section (box) FRP structural shapes was systematically compared. The local buckling is influenced by the unique stresses distribution of each section of the profile shapes. This article reviews the related design parameters to identify the research gaps in order to expand the current design standards and manuals of hollow box PFRP profiles and to broaden their applications in civil structures. Unlike open-section profiles, it was found that local buckling can be avoided for box profiles if the geometric parameters are optimised. The identified research gaps include the effect of the corner (flange-web junction) radius on the local buckling of hollow box PFRP profiles and the interactions between the layup properties, the flange-web slenderness, and the corner geometry (inner and outer corner radii). More research is still needed to address the critical design parameters of layup and geometry controlling the local buckling of pulwound box FRP profiles and quantify their relative contribution and interactions. Considering these interactions can facilitate economic structural designs and guidelines for these profiles, eliminate any conservative assumptions, and update the current design charts and standards. [ABSTRACT FROM AUTHOR]

[Display omitted] • Capture and quantify the waviness and fibre misalignment in reinforced composites including in-plane and out-of-plane waviness. • Improve the computational efficiency and increase the precision of fibre identification. • The image analysis result was used as input to Finite Element (FE) modelling to quantify the effect of fibre waviness on the compressive strength of the full-scale columns. Accurate and cost-effective full-scale measurement of fibre waviness and misalignment in continuous fibre-reinforced composite structures remains a challenge. This study proposes a novel approach of Filtered Canny Misalignment Analysis (FCMA) to capture and quantify in-plane and out-of-plane fibre waviness. The FCMA method measures fibre misalignment from the microscope and Charge Couple Device scan images by a Canny edge detector and a Canny edge filter to effectively identify the true fibre path. The method is systematically evaluated and benchmarked with the existing High Resolution Misalignment Analysis (HRMA) method. The results show that the FCMA method is more robust, efficient, and precise for fibre waviness measurements. The fibre misalignment in selected hollow composite columns is quantified by the FCMA method. The in-plane waviness distribution is used as a material orientation input to a verified finite element model. This simulation demonstrates the effect of fibre waviness on stress distribution for a hollow composite column under axial compression. The FCMA method code is supplied as supplementary material to this paper. [ABSTRACT FROM AUTHOR]

• Drilling holes showed slight decrease in the axial load capacity, stiffness and toughness. • Failure initiation and progression of FRP columns with winding fibre layers led by delamination. • Wound-fibres prevented the spread of the interlaminar crack and facilitated progressive failure. • Placing inserts in the PFRP columns contributed slightly to the axial load resistance and prevented local buckling failure. • DIC technique and FE modelling showed the stress distribution on the PFRP columns with and without holes. Pultruded Fibre Reinforced Polymer (PFRP) composite sections are being implemented extensively in many civil infrastructure applications due to their unique strength- and stiffness-to-weight ratio and non-corrosive nature. After production, PFRP sections are usually subjected to post-processing to enhance their versatility and structural integrity, including drilling holes and placing anti-crush inserts inside the hollow sections. This study investigates the influence of the drilled holes and the incorporated inserts on the compressive behaviour of PFRP sections. The effect of the quantity and diameter of the holes as well as the glued and unglued anti-crushed inserts inside the hollow part of the PFRP section was investigated experimentally. Finite element modelling was employed to simulate and validate the experimental behaviour of the PFRP columns under compressive loading. Digital Image Correlation (DIC) technique, using a high resolusion tracing camera, was utilised to capture the actual strain distribution at the outer surface of the PFRP sections to observe and correlate the impact of the holes and inserts with numerical solutions. Test results showed that the failure modes and load resistance capacity of PFRP columns were insensitive to the number of holes and the hole diameter due to the unique pull-winding manufacturing process, which results in continuous wound fibres around the perimeter. On the contrary, placing internal inserts prevented the occurrence of local buckling with slight enhancement in the axial load capacity. Moreover, delamination failure at the column corners was observed to occur prior to the local buckling and the final failure in the columns without and with inserts, respectively. [ABSTRACT FROM AUTHOR]