Fibre Reinforced Plastic Tubes Research Articles

Axial compressive behavior of self-compacting micro-expansive high-strength concrete confined by glass fiber reinforced plastic tube

To solve the instability of the compression bars in the space truss composed of GFRP tubes, a composite column with high-strength concrete (HSC) confined by glass fiber-reinforced plastic (GFRP) tube was proposed. High-strength self-compacting micro-expansive concrete with a slump greater than 255 mm was produced under normal-temperature curing conditions and confined by GFRP tubes. A mechanical performance test of the GFRP-confined HSC short column under axial compression was performed. The effects of GFRP tube types, concrete expansion agent, constraint effect, ultimate load capacity, and failure mode of the composite structure were discussed and analyzed through the test. A model of the stress-strain response of the GFRP confined HSC column was proposed. The results show that the 45° fiber-wound GFRP tube has a significant restraining effect on the HSC. The stress-strain relationship increases quadratically in a linear fashion. When the composite column was damaged, the GFRP fiber was broken and the concrete was crushed. The ultimate strength was about 1.5 times that of unconstrained HSC columns, and the loading method has less influence on the results. The expansion agent has a significant effect on the deformation performance of the composite column, and its ultimate strain was about 1.4 times that of the composite column without expansion agent.

Compressive Strength Testing of Hybrid Concrete-Filled Fiber-Reinforced Plastic Tubes Confined by Filament Winding

In this study, an experiment on compressive strength of the hybrid concrete-filled fiber-reinforced polymer (FRP) tube (CFFT) confined by filament winding was conducted to improve the longitudinal strength while considering the thickness of filament winding as a variable. A maximum error of 17% was observed when the results of performing the finite element analysis (FEA) by applying the mechanical properties of the fiber-reinforced polymer (FRP) materials suggested in previous studies were compared to those of the compressive strength experiment on the hybrid-CFFT. Moreover, a maximum error of 15% was exhibited when the results derived from the strength equation proposed by analyzing the compressive strength experiment were compared. Furthermore, the compressive strength of the hybrid-CFFT increased by up to 14% when the longitudinal compressive strength of the pre-tensioned spun high strength concrete (PHC) pile and concrete-filled tube (CFT) were compared.

Overall buckling characteristics of slender FRP-foam sandwich tube under axial compression

Compared with laminated FRP (Fiber Reinforced Plastic) tube, FRP-foam sandwich tube can improve the stability of the member and better exert the high strength of FRP. It can be used in civil engineering as compression member with lightweight, high bearing capacity and corrosion resistance. In order to study the compression characteristics of this new type of compression member, axial compression tests on the slender FRP-foam sandwich tubes were carried out compared with laminated composite tube. It was found that the main failure mode is overall buckling of this slender sandwich tube. Then the Perry-Robertson's formula based on the edge failure criterion was adopted as the basic form of the overall stability coefficient calculation formula for the sandwich tube. Afterwards the parameters of the formula were obtained based on the experimental results. As a result, the calculation equation of the overall stability coefficient for the FRP-foam sandwich tube was derived.1

Behavior of geopolymeric recycled aggregate concrete-filled FRP tube (GRACFFT) columns under lateral cyclic loading

In order to improve the environmental sustainability of concrete-filled FRP (fibre-reinforced plastic) tube (CFFT) column, a new kind of composite column, geopolymeric recycled aggregate concrete-filled FRP tube (GRACFFT) column, was proposed in this paper. The hysteretic behaviors of GRACFFT columns were experimentally investigated. The influences of different parameters, i.e., fiber types, section form, and reinforcement type were discussed. Based on the strain analysis, the plastic hinge length and utilization factor of FRP fibers for each GRACFFT column were also investigated. According to the experimental results, it was found that the proposed GRACFFT column showed favorable seismic performance with both high carrying capacity and deformation ability. The proposed GRACFFT column made with carbon FRP tube showed the best seismic behaviors in terms of yield displacement, peak load, ultimate displacement, and cumulative energy consumption. In terms of cross-section, the seismic behaviors of the circular GRACFFT column were better than that of the square column. Also, it was found that the substitution of steel reinforcements with steel tube could effectively increase the seismic behaviors of GRACFFT columns.

Overall buckling prediction model for fibre reinforced plastic laminated tubes with balanced off-axis ply orientations based on Puck failure criteria

Fibre reinforced plastic tubes with balanced off-axis ply orientation exhibit excellent mechanical properties and are widely used in various types of structures. In this study, a theoretical prediction model was proposed to determine the overall buckling load and the failure mode of fibre reinforced plastic laminated tubes with off-axis ply orientation under axial compression. This model considers the transverse shear effect and adopts Puck failure criteria to perform an analysis based on deduced three-dimensional stress and strain fields. A series of carbon fibre reinforced plastics tubes with varying off-axis ply orientations and lengths were designed and prepared. Axial compression tests with effective end-reinforcement and hinge support were performed to validate the proposed prediction model. The results indicated that the predicted model results were in good agreement with the test results, with respect to ultimate loads, failure modes, and locations of failure. Parametric analysis on the influence of transverse shear effect was also conducted, which further explained the influencing degree of transverse shear effect considering different tube lengths, ply sequences, and initial deflection.

The energy-absorbing characteristics of filament wound hybrid carbon fiber-reinforced plastic/polylactic acid tubes with different infill pattern structures

The study aims to investigate the effect of different infill pattern structures on the energy-absorbing characteristics of single filament wound carbon fiber-reinforced plastic tubes, single polyla...

Media Based Forming and Injection Molding Based on Fiber Reinforced Plastic Tubes

Abstract Research and development for industrial applications forces Fraunhofer IWU to explore new fields of technology. The combination of Media Based Forming and Injection Molding (MBF-IM) in a single process is such a new development to meet the requirements on lightweight design and resource efficiency. Based on over 20 years of Fraunhofer IWU experience in hydroforming, this technology development started with the usage of metal tubes and PA6 with glass fiber to produce metal-plastic-hybrid-components the structural strength of the component is realized by the formed metal tube while the molded attachment allows for easy functionalization. Cockpit cross beams (CQB) are known state of the art components produced this way. In a first development step the conventional hydroforming process was replaced by media based forming (MBF) using nitrogen as a pressure medium. With this process the tool can always be kept dry for the injection molding (IM) process without any additional effort, and no subsequent part cleaning is necessary. Together with TU Chemnitz and industrial partners further developments are continuously carried out and still under research. The focus of this strategic cooperation is the development and the usage of plastic tubes for the structural function of the component. The paper shows the development path from the state of the art for the MBF-IM from metal-plastic hybrid components to the replacement of the liquid active medium for the MBF by gaseous nitrogen, the use of endless fiber-reinforced plastic tubes as semi-finished products to the MBF-IM of short-fiber-reinforced plastic tubes.

Fabrication and field testing of spiral-wound membrane modules for CO2 capture from flue gas

A spiral-wound membrane module comprising face compression “O” rings for effective seal of gases was developed, including a spiral-wound membrane element, Plexiglas fiber-reinforced plastic tube, and membrane housing. The spiral-wound membrane modules demonstrated essentially no leakage. The concentration polarization phenomenon was observed at a dry feed gas flow rate of less than 1000 sccm before humidification. Hence, the performances of the spiral-wound membrane modules were evaluated using both dry feed and sweep gas flow rates each at 1000 sccm before humidification at the typical flue gas temperature of 57 °C. The feed and sweep gas pressures were at 1.5 and 1 psig, respectively. By using either a simulated flue gas or an actual flue gas, the spiral-wound membrane modules showed similar performance results with a CO2 permeance of greater than 800 GPU and a CO2/N2 selectivity of more than 140, which were essentially identical to the results obtained from the flat-sheet membrane used for the module fabrication and tested in laboratory with the simulated flue gas. The pressure drops of the modules were satisfactory, i.e., less than 1.5 psi/m. During the field test using the actual flue gas at the National Carbon Capture Center in Wilsonville, Alabama, the performances of the modules revealed some unexpected issues including the feed spacer indentations on the membrane selective layer and the leakage at glue lines. These issues were resolved by improving the spiral-wound membrane module fabrication using a smoother feed spacer and a longer glue curing time. The field test results of the modules have shown their good potential for the post-combustion CO2 capture from coal-fired power plants.

Transformation of the Mechanical Properties of Fiber-Reinforced Plastic Tubes from the Cartesian Coordinate System into the Cylindrical Coordinate System for the Application of Bending Models

Transformation of the Mechanical Properties of Fiber-Reinforced Plastic Tubes from the Cartesian Coordinate System into the Cylindrical Coordinate System for the Application of Bending Models

Modal analysis based on finite element method and experimental validation on carbon fibre composite drive shaft considering steel joints

The finite element method was used to analysis the natural frequencies of the carbon fibre-reinforced plastic tube and carbon fibre reinforced plastic shaft with steel joints, respectively, which showed that there was a remarkable difference between the two results. The difference indicated that the steel joints had influence on carbon fibre reinforced plastic shaft's modes and natural frequencies, and they should be considered in the carbon fibre reinforced plastic shaft dynamic properties. A modal test system was constructed to perform the carbon fibre reinforced plastic shaft specimen's natural frequency measurement through impact technique. The measured natural frequencies and the finite element method calculated measured natural frequencies showed a basic consistency.

Formulation of Design Charts for Composite Submarine Pressure Hulls

This paper describes an experimental and a theoretical finite element (FE) numerical investigation into the collapse of 44 circular cylindrical composite tubes under external hydrostatic pressure. The results for these 44 tubes are from earlier investigations carried out by Ross et al. (2007, 2008), with the resulting design charts building upon earlier work by Ross et al. (1999) and is now presented in a new format for the first time in this paper. The investigations carried out concentrated upon fiber-reinforced plastic tube models, manufactured from a mixture of three carbon and two E-glass fiber layers. The material lay-up was 0 ° / 90 ° / 0° / 90 ° / 0 ° with the carbon fibers being laid lengthwise (0°) and the E-glass fibers being laid circumferentially (90°). The theoretical investigations were carried out using a simple solution for isotropic materials, namely the well-known von Mises Formula, together with FE solutions of a numerical solution. The earlier investigations also used a numerical solution using the software program ANSYS (Canonsburg, PA), however the results of this work were found to be disappointing. The experimental investigations carried out showed that the composite models behaved similarly to isotropic materials previously tested, such that short models suffered collapse through axisymmetric deformation, whilst the longer tubes collapsed through nonsymmetric bifurcation buckling. Additionally, it was discovered that the models suffered failure at changes of the composite lay-up due to the manufacturing process of these particular models and these changes at which failure occurred give the appearance of being the weak points of the models. To carry out the theoretical investigations, two different types of material properties were used for the composite analysis. First, the material properties of the single layers, as supplied by the manufacturer and second, a set of material properties derived experimentally within the engineering laboratory. So as to verify the previously obtained experimental and theoretical results, the identical approach was chosen, in that MisesNP (Portsmouth, UK) was used, which is a program based on the von Mises Formula for single layer isotropic materials. The second theoretical method used two finite element analyses, using the commercial software package ANSYS. Specifically, the ANSYS analyses simulated the composite with a single layer orthographic element (Shell 93) and secondly with a multilayer element (Shell 99). Although the results from Shell 93 and Shell 99 agreed with each other, their predicted buckling pressures were, in general, higher than those predicted by the von Mises analytical method. With respect to the longer models, the von Mises solution produced a more consistent set of results, with the failure mode being elastic instability; this being highlighted when the experimentally obtained material properties were used. Hence the conclusion drawn was that the results obtained via finite element analyses produced buckling pressures that are questionable. This report provides design charts for all 44 models, using all of the theoretical approaches previously adopted, with both theoretically obtained material properties and those material property values obtained experimentally. The resulting design charts have not been previously published for all 44 models combined. These resulting design charts allow the possibility of obtaining a Plastic Knockdown Factor (PKD) for the models under investigation. Once the theoretical buckling pressures have been obtained, using either MisesNP or ANSYS, the theoretical buckling pressures can then be divided by the PKD via the design charts, so as to obtain the predicted buckling pressures. Work has been carried out by Sonardyne International Limited of Yateley, Hampshire, UK, using the design charts of Ross et al. (2007, 2008), in preference to BS5500 (British Standards Institution 2000), with substantial weight savings being made for their pressure vessels.

Formulation of Design Charts for Composite Submarine Pressure Hulls

This paper describes an experimental and a theoretical finite element (FE) numerical investigation into the collapse of 44 circular cylindrical composite tubes under external hydrostatic pressure. The results for these 44 tubes are from earlier investigations carried out by Ross et al. (2007, 2008), with the resulting design charts building upon earlier work by Ross et al. (1999) and is now presented in a new format for the first time in this paper. The investigations carried out concentrated upon fiber-reinforced plastic tube models, manufactured from a mixture of three carbon and two E-glass fiber layers. The material lay-up was 0° / 90° / 0° / 90° / 0° with the carbon fibers being laid lengthwise (0°) and the E-glass fibers being laid circumferentially (90°). The theoretical investigations were carried out using a simple solution for isotropic materials, namely the well-known von Mises Formula, together with FE solutions of a numerical solution. The earlier investigations also used a numerical solution using the software program ANSYS (Canonsburg, PA), however the results of this work were found to be disappointing. The experimental investigations carried out showed that the composite models behaved similarly to isotropic materials previously tested, such that short models suffered collapse through axisymmetric deformation, whilst the longer tubes collapsed through nonsymmetric bifurcation buckling. Additionally, it was discovered that the models suffered failure at changes of the composite lay-up due to the manufacturing process of these particular models and these changes at which failure occurred give the appearance of being the weak points of the models. To carry out the theoretical investigations, two different types of material properties were used for the composite analysis. First, the material properties of the single layers, as supplied by the manufacturer and second, a set of material properties derived experimentally within the engineering laboratory. So as to verify the previously obtained experimental and theoretical results, the identical approach was chosen, in that MisesNP (Portsmouth, UK) was used, which is a program based on the von Mises Formula for single layer isotropic materials. The second theoretical method used two finite element analyses, using the commercial software package ANSYS. Specifically, the ANSYS analyses simulated the composite with a single layer orthographic element (Shell 93) and secondly with a multilayer element (Shell 99). Although the results from Shell 93 and Shell 99 agreed with each other, their predicted buckling pressures were, in general, higher than those predicted by the von Mises analytical method. With respect to the longer models, the von Mises solution produced a more consistent set of results, with the failure mode being elastic instability; this being highlighted when the experimentally obtained material properties were used. Hence the conclusion drawn was that the results obtained via finite element analyses produced buckling pressures that are questionable. This report provides design charts for all 44 models, using all of the theoretical approaches previously adopted, with both theoretically obtained material properties and those material property values obtained experimentally. The resulting design charts have not been previously published for all 44 models combined. These resulting design charts allow the possibility of obtaining a Plastic Knockdown Factor (PKD) for the models under investigation. Once the theoretical buckling pressures have been obtained, using either MisesNP or ANSYS, the theoretical buckling pressures can then be divided by the PKD via the design charts, so as to obtain the predicted buckling pressures. Work has been carried out by Sonardyne International Limited of Yateley, Hampshire, UK, using the design charts of Ross et al. (2007, 2008), in preference to BS5500 (British Standards Institution 2000), with substantial weight savings being made for their pressure vessels.

콘크리트 포장에서 FRP 튜브 다웰바의 역학적 특성 분석

콘크리트 포장의 다웰바는 교통하중을 줄눈 넘어 인접한 슬래브로 전달하는 하중전달장치이다. 현재 국내에서 사용되는 다웰바는 원형봉강으로 교통하중과 환경하중으로 인해 반복적으로 발생하는 전단응력과 휨응력에 대해 높은 내구성을 갖고 있다. 그러나, 강재 다웰바는 장기간 공용시 줄눈틈, 포장 하부 등으로 침투한 수분으로 인해 부식이 발생한다. 특히, 겨울철에 사용되는 제설용 염수와 접촉할 경우 부식은 급격히 진행된다. 다웰바에 부식이 발생하면 부피가 증가하여 줄눈의 거동을 방해하며 유효단면적의 감소로 하중전달효과가 떨어질 수 있다. 이와 함께 지속적인 원자재 가격의 상승으로 강재 다웰바의 가격 경쟁력이 크게 낮아지고 있다. 이러한 강재 다웰바의 문제점은 새로운 재료를 사용한 대체 다웰바의 개발로 이어지고 있다. 본 연구에서는 높은 인장강도, 높은 내부식성을 갖춘 FRP(fiber reinforced plastic)를 튜브 형태로 제작하고 그 속을 고강도 무수축 모르타르로 충진한 FRP 튜브 다웰바에 대한 역학적 두께 설계를 실시하였다. 역학적 두께 설계의 기준으로 다웰바와 콘크리트 면 사이에 발생하는 지압응력을 사용하였다. 지압응력의 산정을 위하여 다웰바에 전달되는 교통하중을 이론식과 유한요소해석을 통해 산출하고 실내시험을 통해 FRP 튜브 다웰바의 물성을 측정하였다. 그 결과, 직경 32mm, 40mm FRP 튜브 다웰바 모두 지압응력 기준을 만족하는 것으로 나타났다. 국내 콘크리트 포장은 콘크리트 슬래브 하부에 강성이 큰 린 콘크리트층을 사용하기 때문에 다웰바에 전달되는 교통하중이 적고 이로 인해 지압응력도 낮아져 상대적으로 적은 직경의 FRP 튜브 다웰바의 사용이 가능한 것으로 판단된다. As well known, dowel bars are used to transfer traffic load acting on one edge to another edge of concrete slab in concrete pavement system. The dowel bars widely used in South Korea are round shape steel bar and they shows satisfactory performance under bending stress which is developed by repetitive traffic loading and environment loading. However, they are not invulnerable to erosion that may be caused by moisture from masonry joint or bottom of the pavement system. Especially, the erosion could rapidly progress with saline to prevent frost of snow in winter time. The problem under this circumstance is that the erosion not only drops strength of the steel dower bar but also comes with volume expansion of the steel dowel bar which can reduce load transferring efficiency of the steel dowel bar. To avoid this erosion problem in reasonable expenses, dowers bars with various materials are being developed. Fiber reinforced plastic(FRP) dower that is presented in this paper is suggested as an alternative of the steel dowel bar and it shows competitive resistance against erosion and tensile stress. The FRP dowel bar is developed in tube shape and is filled with high strength no shrinkage. Several slab thickness designs with the FRP dowel bars are performed by evaluating bearing stress between the dowel bar and concrete slab. To calculated the bearing stresses, theoretical formulation and finite element method(FEM) are utilized with material properties measured from laboratory tests. The results show that both FRP tube dowel bars with diameters of 32mm and 40mm satisfy bearing stress requirement for dowel bars. Also, with consideration that lean concrete is typical material to support concrete slab in South Korea, which means low load transfer efficiency and, therefore, low bearing stress, the FRP tube dowel bar can be used as a replacement of round shape steel bar.

Experimental investigation on the structural behavior of concrete filled FRP tubes with/without steel Re-bar

This study evaluates the mechanical performance of Reinforced Concrete Filled Fiber Reinforced Tube (RCFFT) through compressive and flexural tests for the purpose of applying RCFFT as strut members for a Prestressed Concrete (PSC) Box Girder bridge. Firstly, the compressive behavior of Concrete Filled Fiber Reinforced Plastic Tube (CFFT) and RCFFT members was investigated to examine their confinement effects. Secondly, based on the experimental results, an equation for estimating the ultimate compressive strengths of CFFT and RCFFT was proposed. In addition, the degree of improvement on the flexural performance due to the reinforcement by Fiber Reinforced Plastic (FRP) was analyzed from flexural tests on CFFT and RCFFT. It could be confirmed from the result of this research that the structural performance of RCFFT members were improved. Furthermore, the result of this study might be utilized in the design of the RCFFT strut members of a real PC BOX Girder bridge.

Strength Enhancement of Advanced Grid Stiffened FRP Tube Confined Concrete Cylinders under Fire

Recently, a new confining device - a lattice of interlaced fiber-reinforced plastic (FRP) ribs that were wrapped by an FRP skin, has been developed to provide better confinement to a concrete core through interfacial mechanical interlocking [1,2]. A systematic study has validated the enhanced structural capacities over traditional FRP tube encased concrete counterparts. However, like traditional FRPs, advanced grid stiffened FRP tube confined concrete cylinders (AGS-FRPC) are vulnerable to fire hazards. The purpose of this study was to investigate the enhancement of fire tolerance as a result of incorporating organically modified montmorillonite (MMT) and a traditional fire retardant additive (TSWB®) into a vinyl ester (VE) matrix. Two series of samples were prepared. The first series consisted of groups A, B, C, and D, in which A was regular AGS-FRPC, B was enhanced with MMT, C was enhanced with TSWB® fire retardant additive, and D was enhanced with both MMT and TSWB®. The second series of samples was identical to the first series as a control, and it consisted of groups of E, F, G, and H, respectively. The only difference was that the first series was exposed to a jet fire of 982°C for 5 min while the second series was not. It was found that fire exposure had a significant impact on reducing the residual strength of the confined concrete cylinders. The introduction of MMT increased both the fire tolerance and compressive strength of AGS-FRPC. The TSWB additive was effective in minimizing the effect of the fire hazard, but it reduced the compressive strength.

Analysis of surface roughness parameters in turning of FRP tubes by PCD tool

Fibre-reinforced plastic (FRP) composite materials are used in many engineering field because of its good properties such as high strength, high stiffness, low weight, corrosion resistance, etc. Because of its properties and uses in different manufacturing sectors, it is necessary to carryout the machining tests. This paper presents a study of influence of cutting parameters on surface roughness parameters such as R a, R t, R q, R p and R 3z in turning of glass fibre reinforced composite materials. Empirical models are developed to correlate the machining parameters with surface roughness. Analysis of experimental results is carried out through area graphs and three-dimensional surface plots.

Finite element modelling of the crushing response of composite sandwich panels with FRP tubular reinforcements

The crushing response and the crash energy absorption characteristics of composite sandwich panels with internal fibre reinforced plastic (FRP) tubular reinforcements were investigated in the numerical simulation works described here using the LS-DYNA3D finite element code. Several models were developed in order to simulate a series of compressive tests performed at the National Technical University of Athens using composite sandwich panels with glass FRP faceplates and syntactic foam core that were internally reinforced with FRP tubes, and, moreover, to examine how the construction parameters of the sandwich panels influence the main crushing characteristics, i.e. the crash energy absorption and the peak compressive load. The sandwich construction parameters whose influence was investigated were the properties of some of the constituent materials (more specifically the foam core and the reinforcing FRP tubes) and the geometric characteristics of the internal reinforcements such as the thickness of the FRP tubes. The agreement between the finite element calculations and the experimental results was excellent concerning the load—displacement curve and the main crushing characteristics of the tested hybrid composite materials, as well as the overall crushing response of the sandwich panels in compressive loading, as a result of several refinements that were applied to the finite element models.

The static and dynamic axial collapse of CFRP square tubes: Finite element modelling

In the simulation works described in this paper the LS-DYNA3D explicit finite element code is used to investigate the compressive properties and crushing response of square carbon FRP (fibre reinforced plastic) tubes subjected to static axial compression and impact testing. A series of models was created to simulate some of the static and dynamic tests performed in the National Technical University of Athens using CFRP tubes featured by the same material combination (woven fabric in thermosetting epoxy resin) and external cross-section dimensions, but different length, wall thickness, laminate stacking sequence and fibre volume content. Simulation works focused on modelling the three modes of collapse (i.e. progressive end-crushing with tube wall laminate splaying, local tube-wall buckling and mid-length collapse) observed in the series of static and dynamic compression tests. Satisfactory level of agreement between calculations and test results was obtained regarding the main crushing characteristics of the tested CFRP tubes—such as peak compressive load and crash energy absorption and the overall crushing response—as the finite element models were refined several times in order to obtain optimum results.

Effect of the braiding angle on the energy absorption properties of a hybrid braided FRP tube

Energy absorption is achieved by the combination of various fracture mechanisms such as fibre fracture, delamination, and central crack. However, serious problems would arise if this energy absorption ability were compromised by brittle crack propagation of the cross-sectional central part. In a previous study, the use of flexible resin with lower stiffness and higher toughness than the resin generally used was suggested as a method to restrain brittle crack propagation. In this study, hybrid braided fibre reinforced plastic (FRP) tubes were fabricated according to the previous study involving FRP rods. In this case, the flexible resin was applied to middle-end-fibre. The energy absorption characteristics and crushing mechanisms based on precise cross-sectional observation of the crush zone of the braided FRP tubes with or without the presence of flexible resin in middle-end-fibre were investigated. It was found that braided FRP tubes with or without the presence of flexible resin in middle-end-fibre were investigated. It was found that braided FRP tube with a 30° braiding angle, together with the presence of flexible resins, shows significant improvement in terms of energy absorption ability. The added flexibility of the tubes owing to the addition of flexible resin in turn causes short cracks, more fibre breakage, and consequently enhanced energy absorption properties.

On the response of thin-walled CFRP composite tubular components subjected to static and dynamic axial compressive loading: experimental

In this work the crushing response and crashworthiness characteristics of thin-wall square FRP (fibre reinforced plastic) tubes that were impact tested at high compressive strain rate are compared to the response of the same tubes in static axial compressive loading. The material combination of the tested specimens was carbon fibres in the form of reinforcing woven fabric in epoxy resin, and the tested tubes were constructed trying three different laminate stacking sequences and fibre volume contents on approximately the same square cross-section. Comparison of the static and dynamic crushing characteristics is made by examining the collapse modes, the shape of the load–displacement curves, the peak and average compressive load and the absorbed amount of crushing energy in both loading cases. In addition, the influence of the tube geometry (axial length, aspect ratio and wall thickness), the laminate material properties-such as the fibre volume content and stacking sequence-and the compressive strain rate on the compressive response, the collapse modes, the size of the peak load and the energy absorbing capability of the thin-wall tubes is extensively analysed.