Papers by Keyword: Composite Tube

Abstract: A non-classical mechanical analysis method was used to derive the equivalent torsional stiffness <GI_p> of thick-walled CFRP drive shaft. The equivalent shear modulus calculated by classical lamination theory, finite element analysis method and non-classical mechanical analysis method were compared. Experimental work was carried out on six composite tubes made of same dimensions but different lay-ups. All the results show that the layers with ±45° fiber orientation angle located on the outside of the wall thickness can increase the torsion stiffness of the composite tube. The non-classical mechanical analysis method predicts the torsion stiffness of thick-walled composite tube more precisely than the theory classical lamination, and agree well with experimental results. This method provides a convenient, accurate and fast method for the torsion stiffness.

Abstract: The increasing market share of highly volatile electricity generated from renewable sources like wind or solar energy, leads to enormous challenges in the energy sector. Since large-scale storage systems are neither currently nor in the near future available, the gap between electricity from renewable sources and current electricity demand has to be closed with flexibly operated conventional power plants. In order to be a viable, cost-effective option in tomorrow’s energy market future power plants must be highly efficient while having low CO₂ emissions. Furthermore, they have to be highly reactive to counter instabilities in the electrical grid due to fluctuations in renewable sources. Current materials used in power plants are only within limits suited to experience extreme changes in operational loads. However, extreme changes of operational loads will become increasingly severe with a growing share of renewables. Our project team has developed a new concept for CMC-jacketed pipes to alleviate these issues. Recently, this concept was further developed and tested in laboratory as well as a large-scale application test at Grosskraftwerk Mannheim (GKM). All tests are still ongoing. Additionally, to the use in modern highly efficient power plants such CMC-jacketed piping is also suitable for other high-temperature applications, like e.g. solar power plants or industrial chemical applications.

Abstract: The response of filament-wound composite tubes subjected to pure bending is studied. The decrease of D/t ratios and increase of winding angles improve the ability to resist buckling failure whereas increasing winding angle generates complex trend in material failure. The ultimate failure mode depends on the interaction of D/t ratio and winding angle. FEM results are in good agreement with experiments.

Abstract: Steel-polyurethane tube can be widely used in civil engineering. In this paper, 6 axial compression specimens test was carried out on steel-polyurethane tube, the results showed that the deformation of steel - polyurethane composite tube (SPCT) appears the bow drum, the bonding performance between polyurethane and steel is so good that the peeling did not occur. From the load displacement curve and test process, it can be gotten that specimen curve was generally composed of elastic, elastic-plastic, descent and strengthening phases, and it indicated that SPCT has sound ductility and strength reserve to resist dynamic loads.

Abstract: Composite tube is one new kind of multi-material shell structures. It has both of metal and composite energy absorption advantage. In order to find the energy absorption characteristic of composite tube and put it into use, the Drop-Weight Tear Test (DWTT) was carried out. The LD2Y aluminum was chosen as the inner metal material which was wrapped fiberglass epoxy composite outside. During the test, the displacement signal and velocity signal, acceleration signal were got by piezoelectric acceleration transducer. Furthermore, the DWTT test of the composite tube was simulated in LS-DYNA, and proved the validity of the model by comparing the simulation results with the experiment results. We established the vehicle front longitudinal beam model with the material type of the composite tube, and carried out the simulations of whole car collisions in LS-DYNA according to FMVSS 208. Through the analysis of occupant head injury got from the simulations, we got the result that using the composite tube material could not only elevate the cars safety but also reduce front longitudinal beam weight effectively.

Abstract: The effect of specific absorbed energy on pultruded profile and thin-walled aluminum composite square cross-section tubes were studied via experimentally. The type of strand mat E-glass reinforced polyester resin was conducted in this study. The specimens of square pultruded and thin-walled wrapped strand mat E-glass composite were compressed under quasi-static of obliquely loadings from the top moving plat platen. For each specimen of composite tubes, triggering mechanism was applied on frontal end top of the tube to obtain the progressive failure throughout the crash event. The pultruded profile tube wall-thicknesses of 2.1 mm and thin-walled aluminum 1.9 mm thickness wrapped 3 layer woven fabric were examined, and the effects of crushing behaviors and failure modes were discussed. Results showed that the tubes energy absorption capability was affected significantly by different type of composite made in term of internal energy.

Abstract: The present papers determine the effect of composite pultrusion square tubes E-glass polyester empty and polymeric foam-filled subjected to axial compressive loading. The specimens of square composite pultrusion were compressed experimentally under axial loadings to examine the effect of empty and polymeric foam-filled with different wall-thickness. The wall-thickness was used in this study were 2.1 and 2.4 mm. During the experimental observation, three characteristic crushing stages were identified as initial peak load, progressive crushing and compaction zone stages. The composite pultrusion square tube profile were analyzed and investigated in terms of crashworthiness parameters to meet the improvement of structural material widely used in automobile, aerospace and marine applications. Result obtained from experimental analysis such that initial peak load, mean load, energy absorption and specific energy absorption versus displacement curves were compared for each specimen. Results showed that the tubes energy absorption was affected significantly by different tube profile. It is also found that the polymeric foam-filled exhibit superb crashworthy structure on specific absorbed energy and the amount of initial peak load, mean load and absorbed energy recorded higher than the empty tube profiles.

Abstract: The present investigation deals with the damage behavior of composite tube with pinned-joint holes made by filament winding technique. The pin-loaded holes are tailored to fail mainly with bearing mode. The main objective of the paper is to investigate the stress state and damage behavior of pin-loaded holes made by filament winding. The failure load and the failure mode are analyzed numerically and experimentally. A good agreement between experimental results and numerical predictions is obtained.

Abstract: The three-dimensional numerical simulation model of two polymer melts flowing through the traffic circle section path was founded. The coextrusion process of composite pipe was simulated used the finite element method. The stream line method was used to simulate the extrudate swell. Such simulated results as the location and shape of coextrusion interface, the shear stress profile were analyzed. It is found that the maximum shear rate occur near the convergence section of the outer polymer. The interface excursion is less than 1mm in the die path. As the melt flow out of the die, the interface excursion increase distinctly, the value is up to 6mm. The extrudate swell rate is 21% along the radial direction.

Abstract: An experimental investigation on the lateral collapse behaviour of woven fabric glass/epoxy composite tubes under quasi-static and impact loads are presented here. Composite tubes of different diameter to thickness ratios (D/t = 5.33 - 20.67) were compressed between two flat platens or by a short width square indenter. Impact tests were performed at the gravity drop hammer test setup. The fracture process and the energy absorption capability of the composite tubes under quasi-static and impact loads were studied. It was observed that, the lateral collapse mechanism of thick composite tubes (D/t < 10) was different from thinner tubes (D/t > 10). Finally, the progressive failure analysis of the composite tube was performed in finite element software ABAQUS. Good agreement was observed between the experimental results and numerical predictions.