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This paper presents a procedure for the application of a multifractal spectrum to analyse vibration signals obtained during static bending tests of selected fibre reinforced polymer matrix composite materials. The analyses were designed to determine the failure course of the composites tested under bending conditions. Non-stationary changes occurring in the signals include low- and high-energy symptoms of progressive damage in materials, which are difficult to identify and interpret, especially in the early stages. Determined using fractal leaders, the multifractal spectra of the vibration signals calculated for the different stages of the bending test allowed qualitative identification of the changes caused by progressive damage with different energy responses. In addition, the quantitative measures of change in the characteristics of the multifractal spectrum determined clearly indicated the changes occurring in the recorded signals. It can be concluded from the research that the proposed signal processing method based on a multifractal spectrum determined from non-stationary vibration signals is sensitive to changes occurring in these signals. [ABSTRACT FROM AUTHOR]

As a composite material, fibre reinforced polymer (FRP) has many uses. Incorporating FRP composite material enhances the reinforced concrete beams’ (RCB) performance, properties and behaviour as external reinforcement. A summary of how different FRP influences the RCB properties should be studied. This review paper discusses the use of FRP to reinforce RCB and briefly describes the topic. Previous experimental studies and finite element analysis (FEA) results showed that RCB constructed with FRP significantly improved the axial load, load-deflection, ultimate load, crack propagation, stress-strain distribution, and failure mode of RCB. Since this FRP composite material has superior strength, force, mounting and anchoring properties, it can be used as an alternate exterior reinforcement in RCB. The structural behaviour and performance of RCB can be enhanced by utilising FRP composite material in civil and structural engineering, especially in building construction projects.

Adopting novel sandwich structures with FRP (Fibre Reinforced Polymer) skins and a metallic lattice core, both of which have high specific strength and stiffness, is one way to achieve better mechanical performance while remaining lightweight. Flexural stress is a load pattern that frequently occurs in the structural frame components of automobiles; nonetheless, while the in-plane load scheme has scarcely been examined, the out-of-plane load one has. As a result, the former configuration received consideration in this work. Moreover, short beam specimens were taken into account. The mechanical response of specimens with three different kinds of composite materials as skin material was analysed. The skins were made of CFRP (Carbon Fiber Reinforced Polymer), with two different weaving styles, and AFRP (Aramid Fiber Reinforced Polymer). All-titanium specimens were studied, too. Similar maximum loads and maximum displacement at break were recorded for both CFRP and AFRP specimens, while the all-titanium one resulted stronger. In terms of the load-displacement curves, the first section featured an initial linear phase, followed by a minor load drop, likely attributed to the breakage of fibres. The CFRP specimens showed a sharp fracture of the skin fibres, while for the AFRP, a fraying was observed.

As a composite material, fibre reinforced polymer (FRP) has many uses. Incorporating FRP composite material enhances the reinforced concrete beams' (RCB) performance, properties and behaviour as external reinforcement. A summary of how different FRP influences the RCB properties should be studied. This review paper discusses the use of FRP to reinforce RCB and briefly describes the topic. Previous experimental studies and finite element analysis (FEA) results showed that RCB constructed with FRP significantly improved the axial load, load-deflection, ultimate load, crack propagation, stress-strain distribution, and failure mode of RCB. Since this FRP composite material has superior strength, force, mounting and anchoring properties, it can be used as an alternate exterior reinforcement in RCB. The structural behaviour and performance of RCB can be enhanced by utilising FRP composite material in civil and structural engineering, especially in building construction projects. [ABSTRACT FROM AUTHOR]

This article explores the behavior of short beam specimens made from a titanium/fiber-reinforced polymer (FRP) hybrid sandwich material. The study compares the flexural characteristics of specimens with FRP skins and titanium skins, which were manufactured using additive manufacturing processes. Three-point bending tests were conducted to evaluate the mechanical properties of the specimens. The results provide insights into the fracture mechanisms and performance of the hybrid sandwich material. The study found that titanium-skinned specimens had the highest strength, while aramid and carbon fiber skins had comparable mechanical characteristics. The article also includes micrographs of the fracture surfaces and compares the performance indexes of the different specimens. [Extracted from the article]

Research related to stab-resistant armour is focused on developing a low-weight flexible stab-resistant armour. Various materials and methods have been used to reduce the overall bulk but managing the flexibility and bulk with improved stab resistance is still a challenge for the researchers. In this study, flexible stab-resistant material for stab-resistant personal protective equipments (PPEs) has been developed by using shear thickening fluid (STF) treated fabric made of multicomponent yarns and ultra high molecular weight polyethylene (UHMWPE) laminate composite. The stab resistance and comfort behaviour like flexural rigidity and areal density were investigated with respect to number of layers and different STF concentrations according to VPAM KDIW-2004 and respective standards for flexural rigidity. Laminate-Woven hybrid composite was developed to reduce the bulk of the panel while maintaining the required protection level. [ABSTRACT FROM AUTHOR]

Despite recent advancements in using machine learning (ML) techniques to establish the microstructure-property linkage for composites’ representative volume elements (RVEs), challenges persist in effectively characterising the effect of microstructural randomness on material properties. This complexity arises from the difficulty of expressing randomness as definitive variables and its intertwined relations with other factors, such as material constituents. Such complexities result in limitations in generalising ML models across different material constituents. Conventional solutions to these challenges usually necessitate large datasets, which require considerable computational resources, for an accurate and generalisable ML models to be trained. This paper presents an innovative approach to tackling these challenges by integrating a high-accuracy convolutional neural network (CNN) with a novel microstructure-factored constitutive model (MCM). The MCM, rooted from classic empirical constitutive modelling, effectively segregates the microstructural and constituting material effects, extending the generalisability and thus significantly enhancing the efficacy of the CNN. This new approach enabled a CNN trained on the transverse stress-strain curves of one set of material constituents (CF/PEEK at 270 °C) to be generalised for the rapid prediction of various sets of material constituents at different temperatures, unseen by the CNN during training, with an average mean absolute percentage error around 3 %.

Adopting novel sandwich structures with FRP (Fibre Reinforced Polymer) skins and a metallic lattice core, both of which have high specific strength and stiffness, is one way to achieve better mechanical performance while remaining lightweight. Flexural stress is a load pattern that frequently occurs in the structural frame components of automobiles; nonetheless, while the in-plane load scheme has scarcely been examined, the out-of-plane load one has. As a result, the former configuration received consideration in this work. Moreover, short beam specimens were taken into account. The mechanical response of specimens with three different kinds of composite materials as skin material was analysed. The skins were made of CFRP (Carbon Fiber Reinforced Polymer), with two different weaving styles, and AFRP (Aramid Fiber Reinforced Polymer). All-titanium specimens were studied, too. Similar maximum loads and maximum displacement at break were recorded for both CFRP and AFRP specimens, while the all-titanium one resulted stronger. In terms of the load-displacement curves, the first section featured an initial linear phase, followed by a minor load drop, likely attributed to the breakage of fibres. The CFRP specimens showed a sharp fracture of the skin fibres, while for the AFRP, a fraying was observed.

Precision machining of Fibre Reinforced Polymer (FRP) Composites needs to be explored further while addressing advanced engineering applications. However, force and temperature-driven damages while machining FRP composites, due to the non-homogenous and low thermal conducting behaviour of fibre-matrix interfaces, place the barrier in this direction. Surface machining using abrasive wheels has been projected as a promising option for fine removal of material in FRPs. However, conventional dry grinding strategy exhibited high grinding force due to continuous interaction of abrasive cutting edges, leading to accumulation of heat at the grinding interface. As the cutting action is continuous, heat dissipation also becomes difficult in this situation. Temperature-driven damages on composite matrix and subsequent failure of reinforced fibres were serious concerns in this case. Although attempted in some situations, usage of cutting fluids was not recommended fully due to wetting effects and agglomeration of swarf that hinder the grinding efficiency. Eccentric Sleeve Grinding (ESG), using an intermittent-progressive cuttings scheme, is proposed in this work as a potential dry grinding strategy for FRPs. Control of heat accumulation through progressive cutting strategy and enhancement of heat dissipation through intermittency in cutting cycle appears to be the unique characteristics of ESG. Experimentation of ESG on carbon fibre reinforced composite samples showed promising grinding temperature reduction, which was justified through a significant reduction in grinding forces, surface defects and roughness. [ABSTRACT FROM AUTHOR]

To recycle the coal gangue more economically and effectively, the basalt fiber reinforced polymer (BFRP) and coal gangue concrete (CGC) are combined to form a novel supporting structure in the underground mines, BFRP-confined CGC (FCGC). However, the underground mine environment is rich in sulfate corrosive ions, and meanwhile, the structure is subjected to a high sustained load. Thus, this paper presents an experimental and theoretical investigation on the long-term deformation properties of FCGC under sulfate and high stress conditions. The effects of inner concrete, FRP layer, stress-to-strength ratio, sulfate concentration and load duration time on the shrinkage and creep behavior were clarified in detail. The findings indicate that the shrinkage of FCGC is relatively lower as the BFRP confinement weakens the moisture exchange between inner CGC and external environment. In addition, under sulfate and high stress conditions, the creep strain and specific creep increase continuously in the early stage, while the growth rate gradually slows down in the later stage, where the high stress-to-strength ratio is the key factor. Moreover, when compared with a single high stress condition, the creep strain of FCGC is relatively larger under sulfate and high stress coupling conditions, attributed to the sulfate corrosion on the BFRP wraps. Theoretically, the ACI 209 was modified to predict the nonlinear creep of CGC, by introducing the coal gangue influence coefficient and the increasing coefficient of nonlinear creep. Furthermore, based on the creep model of CGC and BFRP, the nonlinear calculation model of FCGC was developed considering the creep of CGC under a triaxial-stress state and the interaction between inner CGC and BFRP confinement. Validations against the experimental results show that the nonlinear creep model of FCGC works well. • FRP-confined coal gangue concrete (FCGC) was used as a structural filling member. • Creep test of FCGC under sulfate and high stress conditions was systematically conducted. • Stress-to-strength ratio is the key factor affecting the creep deformation of FCGC. • Sulfate corrosion weakens the confinement of BFRP and increases the creep strain of FCGC. • Nonlinear creep calculation model of FCGC was developed considering a triaxial-stress state. [ABSTRACT FROM AUTHOR]

Fibre reinforced polymer (FRP) composite is a useful material. It has been utilised to enhance the structural behaviour of reinforced concrete beams (RCB). It is also crucial to summarise the impact of FRP on various types of RCB properties. This study summarises the FRP usage's impact on the RCB's structural behaviour based on previous research by reviewing and discussing the experimental study and finite element analysis (FEA) results. Based on previous relevant literature reviews, the experimental investigation and FEA showed significant improvements in flexure, stiffness, young modulus, load-deflection, ultimate load capacity, fracture pattern, and failure mode when FRP was used in RCB production. This FRP composite material can be used as the external reinforcement for RCB due to its high strength capability, force, load, and corrosion resistance with adhesive and anchorage properties. Using FRP in RCB can benefit civil engineering by increasing its structural behaviour and performance, especially in construction industry.

Synthetic fibre reinforced polymer (FRP) composite materials have been widely used in engineering fields, e.g., civil, automotive, and aerospace industry, due to their high specific modulus and strength, corrosion resistance, and relatively high durability. The interface between fibre and polymer matrix is critical for the short-term and long-term performance of the FRP composite materials due to the shear lag stress transfer from the matrix to the fibre via their interface. This paper presents an overview of the fibre–matrix interface and interfacial properties. First, the interface mechanisms (i.e., interdiffusion, chemical bonding and mechanical interlocking) of FRP composites are discussed. Next, the methodology for measuring interfacial properties, characterizing interface morphology and chemical composition, and numerical simulations on FRP interface are introduced. Lastly, the challenges for the characterization of interfacial properties are highlighted.

Many researchers worldwide have extensively used fibre-reinforced polymer (FRP) strengthening materials to enhance the shear and flexural strengths of reinforced concrete (RC) beams. However, Studies on strengthening of RC beam subjected to combined torsion and bending moment using both spiral and vertical strip configuration of CFRP that explored in this study is rare. This study aims to demonstrate the behaviour of RC beams strengthened with FRP sheets (strips) with different configurations and subjected to combined actions of torsion and bending moment. Eight beams with a dimension of 15 × 25 × 200 cm were cast. One of the beams was not strengthened, but the others were strengthened with carbon FRP. The angle of twist at torque intervals, first cracking torque, ultimate torque and ultimate twist angle of the conventional and strengthened beams during the testing process were compared. Results showed a significant improvement in the torsional performance of RC beams using carbon FRP. The fully wrapped beams performed better than the beams with strip wrapping due to the influence of various wrapping configurations. Amongst the wrapping configurations of FRP fabrics, the 45° spiral strip wrapping configuration was the most effective for RC beam strengthening in terms of torsion resistance. Reinforced concrete (RC) beams strengthened with fiber reinforced polymer composite were tested under combined bending and torsional moment; The effect of composite orientation, spacing and number of plies on the torsional response; Ultimate torsional moments of RC beams; Twist angle of rotation of control and strengthened beams; Analytical prediction for CFRP material contributions to the ultimate torsional moment of strengthened RC beam. [ABSTRACT FROM AUTHOR]

This paper presents the geometry and material distribution influence on energy absorption systems and failure mode of glass epoxy tubes and carbon epoxy tubes in order to improve the structural performances. Experiments were carried out on different types of composite tubes subjected to axial compression load. After collecting the results of the crushing and drawing the load–displacement curve, the initial failure load, maximum crushing load and average load were found. From these parameters, the crashworthiness parameters were calculated. The comparison results between the parameters showed that the best structure of the glass epoxy tubes was the circular tube with eight layers, where produced the highest specific energy absorption at a value of 21.23 kJ/kg. [ABSTRACT FROM AUTHOR]

Integrating foil sensors into fibre-reinforced plastics offers the advantage of making manufacturing measurable with spatial resolution and thus simplifies quality control. One challenge here is the possible negative influence of the integrated sensors on the mechanical behaviour of the structure. This article shows how the different parts of a film sensor influence important mechanical strength parameters of fibre composites. A comparison of two thermoplastic carrier films shows that by choosing polyetherimide (PEI) instead of polyimide (PI), a considerably more advantageous failure behaviour of the composite is achieved. While integrated PI films reduce the interlaminar shear strength by 68%, no impairment is noticeable due to PEI films. For the critical energy release rate, PEI-based film sensors even lead to a significant increase, while a significant deterioration of 85% can be observed for PI-based sensors. However, not only the film substrate plays a decisive role for the interlaminar shear strength, but also the sensor structures themselves. In this article, sensor structures made of gold were investigated. The decisive parameter for the impairment seems to be the area share of gold structures in the sensor. For a sensor pattern made of gold lines with an area filling of 50%, a reduction of the interlaminar shear strength of up to 25% was observed depending on the angle between the shear stress and the gold lines. No impairment was observed for sensor structures with less gold area. The results show that PEI substrates can be a superior alternative for sensor integration into fibre composites and suggest that there is a trade-off between sensitivity and degradation of mechanical properties when designing interdigital sensors. [ABSTRACT FROM AUTHOR]

Strengthening of masonry walls using Fibre Reinforced Polymers (FRP) sheets have shown to improve the lateral (in-plane and out-of-plane) resistance and deformation characteristics. While the improvements in shear and flexural resistances of FRP strengthened masonry are well understood, their simultaneous influence on the compression resistance of the masonry is not well explored. Therefore, this study aimed to understand the contribution of Carbon Fibre Reinforced Polymer (CFRP) strengthening on the concentric and eccentric compression strength and deformation characteristics of masonry wallettes. Two types of clay bricks were used to construct the masonry wallettes with a commonly used cement-sand mortar. In total, 36 masonry wallettes were experimentally tested under concentric and eccentric compression. The tests results are presented and discussed in terms of observed failure modes, compressive strengths and axial deformation characteristics derived. The failure of the CFRP strengthened wallettes were mainly attributed by crushing failure of masonry. The transverse stain readings of CFRP sheets on the wallettes confirm that the composite action exists in the CFRP strengthened masonry wallettes. Further, CFRP strengthened wallettes tested under concentric compression have shown to improve the compression resistance only about 10–20 %. The stiffness and ductility of the wallettes strengthened with CFRP has improved (20–30 %) compared to the un-strengthened wallettes. Therefore it can be said that, although the CFRP application can improve the shear and flexural resistances, it does not significantly enhance the compressive strength and ductility, as the compression failure was governed by masonry crushing.

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This paper describe, how multiple CAE Analysis Simulations were evaluated to verify the influence of the filler in polymer matrix, by checking the differences in weight, density and maximum limit on tensile analysis(MPa) for each polymer composite (PA-MWCNT & PA-CF). Fibre reinforced polymer (FRP) composites were incorporated at different loadings of 10 wt. %., 20 wt. %., and 30 wt. %. Statistical Analysis results, reveals that high tensile limit has been achieved, when the addition of 30 wt. % of CF filler in the PA66 polymer matrix has been added. This paper explore the potential for a novel type of composite material incorporating carbon fibre (CF) and multi walled carbon nanotube (MWCNT). Recent work has shown that notable improvements in mechanical performance are achievable in reinforced polymers [1]. [ABSTRACT FROM AUTHOR]

Near-surface mounted reinforcement system using fibre reinforced polymer bars has been widely considered as an accepted system for strengthening of reinforced concrete columns, particularly with respect to increasing the flexural resistance. It involves cutting grooves into the concrete cover and bonding laminates inside the grooves with fillers (either epoxy resin or cement mortar) ensuring proper bond between fibre reinforced polymer laminate and concrete to prevent premature failure (debonding of laminate). Near-surface mounting does not require extensive surface preparation and takes minimum installation time than externally bonded fibre reinforced polymer. Unlike conventional fibre reinforced polymer jacketing technology, the efficiency of near-surface mounted bars does not depend on the geometry of the column cross-section as well. Previous experimental studies indicate that strengthening using near-surface mounting increases the lateral strength capacity and energy dissipation capacity of reinforced concrete columns. However, the scope of employing a strengthening system for structural retrofits is constrained by the limitations of the material used for strengthening. The lack of adequate confinement results in reduced ductility and energy dissipation capacity for columns strengthened using near-surface mounted technique, particularly under increased loading eccentricities. Jacketing of columns using fibre reinforced polymer increases confinement; however, the efficiency was observed to be reduced at increased loading eccentricities. Similarly, the flexural capacity and drift capacity under low levels of axial load were not observed to be significantly enhanced by the use of fibre reinforced polymer jacketing. Previous studies have indicated that a combination of these two systems could provide effective behaviour for reinforced concrete columns under eccentric loading. Therefore, this research focuses on utilizing a combination of these two methods in the form of a hybrid fibre reinforced polymer reinforcing system consisting of near-surface mounted bars and fibre reinforced polymer confinement to study the structural response of strengthened reinforced concrete columns under eccentric axial compression. [ABSTRACT FROM AUTHOR]

Fibre reinforced polymer (FRP) is extensively applied in the field of maintenance and reinforcement. In the actual reinforcement of concrete structures, most reinforced concrete (RC) members are in a cracked state and the existing calculation methods seldom consider the initial damage of concrete, especially the effect of severe damage on the crack of RC members. Therefore, it is necessary to propose a model for accurately evaluating the crack width of the repaired different damage state concrete members with carbon fiber reinforced plastic (CFRP) sheet. This study presents an experimental investigation on the crack behaviors of the CFRP sheet flexural-strengthened pre-damaged RC beams based on the results of an experimental program involving ten specimens. The influence of the pre-damaged level, reinforcement ratio and CFRP sheet strengthening layer on the crack development, failure characteristics, crack spacing and crack width is analyzed and discussed. Taking into account the influence of the CFRP sheet strengthening layer and pre-damaged level, a formula for predicting the average crack spacing is proposed, and then an analytical model for the crack width prediction of the flexural-strengthened high pre-damaged beams is established based on the calculation model of the crack width of the ordinary RC beams. The predicted results agree well with test values including data of this study and experimental data of 64 sets of references. [ABSTRACT FROM AUTHOR]

Lack of post-yield stiffness and corrosion resistance could inevitably result in a considerable loss of seismic performance for steel reinforced concrete (RC) piers. Fibre reinforced polymer (FRP) reinforcement can provide high tensile strength and protection from corrosion. To achieve a better post-yield stiffness and durability for piers, FRP/steel double-reinforced configurations were designed by the proposed flexural-capacity design method. A seismic fragility assessment was also conducted to investigate the effectiveness of design parameters, namely the ultimate tensile strength of FRP reinforcement, elastic modulus of FRP reinforcement, and ratio of steel reinforcement for a double-reinforced configuration to that for a steel RC configuration ( ρ steel / ρ prototype ). The results demonstrated that the FRP/steel double-reinforced piers satisfied the mentioned objectives, while the fragility of these piers was a 30.2% less than that of conventional steel RC piers. A 79.9% higher median PGA at the collapse damage state was achieved, when the elastic modulus of FRP reinforcement changed from 164 to 80.7 GPa. An increase in the median PGA of 34.8% can be achieved along with the increase of the ultimate tensile strength of FRP reinforcement. When ρ steel / ρ prototype was approximately 66%, FRP reinforcement exhibited the highest effectiveness on the seismic performance of piers. [ABSTRACT FROM AUTHOR]

Abstract This paper considers the use of Nonlinear Finite Element Analysis (NLFEA) to predict the load capacity of a range of experimentally tested in-plane restrained reinforced concrete slabs which experienced internal arching effects under loading. The slabs were constructed at one third scale and strengthened with basalt fibre reinforced polymer (BFRP) or carbon fibre reinforced polymer (CFRP) bonded in place using the near surface mounted (NSM) technique. As the research was representative of existing floor slabs within reinforced concrete building frames, all test specimens were constructed with normal strength concrete (∼40 N/mm2) and 0.15% steel reinforcement. One tenth of one percent fibre reinforced polymer (FRP) was used to strengthen samples which were compared with unstrengthened control specimens. The London University Structural Analysis System (LUSAS) finite element analysis software package was used to model all test samples using experimentally derived material test values. Experiments and NLFEA models were compared with the Queen's University Belfast (QUB) arching theory which showed that LUSAS was slightly more accurate than the QUB arching theory in predicting slab capacity. However, the QUB arching theory was found to be slightly more consistent in estimating slab capacities compared with LUSAS. Yet, both of these methods were significantly better at predicting slab capacities than existing Eurocode and American Concrete Institute codes. [ABSTRACT FROM AUTHOR]

Abstract This paper outlines basalt fibre reinforced polymer (BFRP) and carbon fibre reinforced polymer (CFRP) strengthening of laterally restrained concrete floor slabs. In-plane restraint has previously been shown to enhance slab capacity due to the development of internal compressive membrane action (CMA), which is not generally included in codified strength assessments. By installing fibre reinforced polymers (FRPs) using the near surface mounted (NSM) technique, disturbance to the existing structure can be minimised. The span-to-depth ratios of test slabs were 20 and 15 and these were constructed with normal strength concrete (∼40 N/mm2) with 0.15% steel reinforcement. 0.10% FRP (either BFRP or CFRP), was used to strengthen samples which were then compared with control samples. Investigations showed that FRP strengthening and CMA are generally separate, with limited overlap in terms of their contribution to capacity increase. Recommendations are then made for designers to better determine the capacity of FRP strengthened restrained slabs. [ABSTRACT FROM AUTHOR]

Increasing importance is being attached to materials in the life-cycle of a building. In the Netherlands, material life-cycle assessments (LCA) are now mandatory for almost all new buildings, on which basis the building is then awarded a building environmental performance or MPG [Milieuprestatie Gebouwen] score. The objective of this study is to reduce the environmental–economic (shadow) costs of precast reinforced concrete (RC) beams in a conventional Dutch office building, thereby improving its MPG score. Two main optimizations are introduced: first, the amount of concrete is reduced, designing a cavity in the cross-section of the beam; second, part of the reinforcement is replaced with a fibre reinforced polymer (FRP) tube. The structural calculations draw from a combination of several codes and FRP recommendations. Hollow FRP-RC beams (with an elongated oval cavity), and flax, glass, and kenaf fibre tubes yielded the lowest shadow costs. In particular, the flax tube obtained shadow costs that were 39% lower than those of the hollow RC beam (with an elongated oval cavity); which also contributed to decreasing the shadow costs of other building components (e.g., facade), thereby reducing the MPG score of the building. However, this study also shows that it is important to select the right type of FRP as hemp fibre tubes resulted in a 98% increase in shadow costs. [ABSTRACT FROM AUTHOR]

Highlights • A life time assessment is shown, to consider anisotropic material behaviour. • Essential material-models are described based on test results. • Simulation results are validated by test results on a real part. Abstract Lifetime assessment at an early stage of a development process is essential to ensure an optimal solution. Classical approaches are often limited to isotropic materials like metals. This paper presents an approach to deal with anisotropic materials using the example of short fibre reinforced plastics (sfr). Therefore, a given work flow, consisting the manufacturing process and the micro structure, is extended by the direction-depended non-linear material behaviour. Furthermore the crucial points of lifetime assessment are pointed out. Starting from a process simulation the influence of a manufacturing process on the local material properties is captured for an finite element analysis. In interaction with micro mechanical models an anisotropic stress field can be calculated which then can be used in the lifetime calculation. To characterize the material and adapt required material-models quasi static as well as cyclic tests were performed. Finally the lifetime can be calculated based on the concept of local S/N-curves. Following this enhanced method, a part equitable life time assessment can be performed independent of geometry. Compared to other methods the local material behaviour and local loads are captured over the whole structure. This provides a time and cost efficient life time prediction even on large structures. Since software tools are available for all simulation steps the presented method provides a time and cost efficient life time prediction even on big structures. [ABSTRACT FROM AUTHOR]

This paper presents experimental and numerical assessments into the compressive stress-strain behaviour of circular FRP-confined rubberised alkali-activated concrete with unidirectional sheets incorporating fibres in the hoop direction. The parameters investigated in the experimental programme include three different rubber contents of 0%, 30% and 60% volumetric replacement of the total natural aggregates and three confinement levels of 1–3 aramid FRP layers. The numerical assessment is performed in ABAQUS/CAE and a new strain hardening-softening function is developed for the compressive behaviour in the Concrete Damaged Plasticity material model, which captures the passive confinement imparted by the FRP jacket on the rubberised concrete. The numerical results are validated against the experimental results and a parametric study involving 240 models covering a wide range of parameters, including varying FRP materials (basalt, glass, aramid, and carbon), reference concrete grades, rubber replacement ratios, and confinement levels, is performed. The experimental results show an increase in the confinement effectiveness, i.e., confined-to-unconfined strength, by 66.7% and 103.4% for specimens with 0% and 60% crumb rubber replacement ratio, respectively, as the number of FRP layers increase from 1 to 3. Test specimens with 0% and 60% crumb rubber replacement ratio indicate an increase in the ultimate axial strain by 228.2% and 76.2%, respectively, as the number of FRP layers increase from 1 to 3. The observed hoop rupture strain reduces by 32.8% and 21.3% for specimens with 0% and 60% crumb rubber replacement ratio as the number of FRP layers increase from 1 to 3, showing a trend of reduction in the hoop rupture strain with higher FRP confinement layers and rubber content. The numerical results show that the enhancement in compressive strength is linearly proportional to the confinement ratio and is only marginally influenced by the FRP jacket stiffness at a given confinement ratio. The ultimate axial strain enhancement is also linearly proportional to the confinement ratio but is dependent on the FRP jacket stiffness. The compressive stress-strain curve for sufficiently confined specimens is also shown to be well represented by a bi-linear curve with hardening. Based on the findings, a design-oriented model is introduced for sufficiently confined specimens and is shown to be in close agreement with the experimental results. • Experimental and numerical assessments of axial compressive behaviour are presented. • Specimens with up to 60% volumetric rubber replacement of mineral aggregates are considered. • Different FRP jacket material properties and thicknesses are investigated. • A design-oriented constitutive model for adequately confined specimens is proposed. [ABSTRACT FROM AUTHOR]

• Research advancement in web crippling of pultruded GFRP profiles is reviewed. • A complete database of experimental results in the literature is documented. • Factors influencing web crippling of pultruded GFRP profiles are analysed. • Numerical modelling is reviewed and paths for improvement are proposed. • Analytical models are summarized and their accuracy is assessed. • Key research gaps are identified and future research directions are recommended. Web crippling involves the failure of pultruded glass fibre reinforced polymer (GFRP) profiles under transverse concentrated loading. The possible failure modes include web buckling, web crushing and web-flange junction failure, which are very different from those of metallic sections, which are isotropic and yield. This paper provides a comprehensive review of the up-to-date research advancement in web crippling of pultruded GFRP profiles from four perspectives. Firstly, the experimental results available in the literature are summarized and a database is tabulated. Secondly, the factors influencing failure modes and web crippling resistance are analysed, including loading conditions, section geometries, and material properties. Thirdly, recent advancement in numerical modelling is reviewed and paths for improvement are identified. Lastly, analytical models for predicting web crippling resistance are reviewed and their accuracy is assessed by comparing predictions with experimental results from the database. It is concluded that this research area is still in its early stages and more experiments need to be conducted, in a standardized and systematic manner; in addition, more detailed material properties should be characterized for a better interpretation of the failure mechanisms. Accurate and reliable analytical models covering all design cases are not yet available, and most existing analytical models still need to be validated with independent experimental data. Finally, the paper identifies key research gaps and proposes future research directions. This paper also provides a benchmark for the future development of design provisions regarding the web crippling of pultruded GFRP profiles. [ABSTRACT FROM AUTHOR]