Search

'Friction Stir Processing (FSP)' is an unconventional grain refinement technique. This metallurgical process is derived from a welding technique known as 'Friction Stir Welding (FSW).' FSP changes various mechanical properties of the base material, including ductility/elongation, fatigue properties, static mechanical properties, corrosion properties, hardness, etc. This study focuses on determining the effect of FSP on mechanical properties of commercially available square aluminium tubes. Different combinations of processing parameters namely, tool rotation speed and tool travel rate are considered during the experimentation. In all five different combinations of processing parameters are tested here. Other parameters such as tool depth, tool path, tool geometry etc. are not altered in the entire course of this investigation. The tensile strength was measured to evaluate mechanical properties of the tube material. Tensile specimens are sectioned from the friction stir processed side-walls of aluminium tubes in such a way so that the processed area occupies the central region along the length the tensile specimen. All the specimens are tested for their tensile behaviour under uni-axial quasi-static tensile loading using Universal Testing Machine (UTM). An appreciable difference is observed in tensile behaviour of specimens due to friction stir processing. [ABSTRACT FROM AUTHOR]

Experimental and numerical investigations of concrete-filled double-skin aluminium stub column with a circular hollow section as the outer skin and a square hollow section as the inner skin are presented in this article. A test program was carried out to study the influences of aluminium tube geometric dimensions and concrete strength on structural performance and strength of composite columns. A series of composite columns was tested on outer circular hollow section tubes and inner square hollow section tubes; the spaces between them had been filled with concrete of different nominal cylinder strengths of 40, 70 and 100 MPa. The tubes were fabricated by extrusion using 6061T6 heat-treated aluminium alloy having a nominal 0.2% proof stress of 240 MPa. A non-linear finite element model was developed and verified against experimental results. The test and numerical results were compared with the design strengths to evaluate the applicability of the design rules in the American specifications for aluminium and concrete structures. In addition, the proposed design equations, developed by the authors for concrete-filled double-skin aluminium tubular stub columns with circular hollow section as both outer and inner skins, were used to calculate the design strengths and compared with the experimental and numerical results obtained in this study. The proposed design equations also predicted the ultimate strengths of the concrete-filled double-skin aluminium tubular stub columns accurately with circular hollow section as the outer skin and square hollow section as the inner skin. [ABSTRACT FROM AUTHOR]

To study the impact of different semi-solid dosage form components on the leaching of Bisphenol A (BPA) and Bisphenol A diglycidyl ether (BADGE) from the epoxy resin-based inner lacquer of aluminium tubes, the tubes were filled with different matrix preparations and stored at an elevated temperature. Despite compliance with the European Standards EN 15348 and EN 15766 on porosity and polymerisation of internal coatings of aluminium tubes, the commercially available tubes used in the study contained an increased amount of polymerisation residues, such as unbound BPA, BADGE and BADGE derivatives in the lacquer, as determined by acetonitrile extraction. Storage of Macrogol ointments in these tubes resulted in an almost quantitative migration of the unbound polymerisation residues from the coating into the ointment. In addition, due to alterations observed in the RP-HPLC chromatograms of the matrix spiked with BADGE and BADGE derivatives it is supposed that the leachates can react with formulation components. The contamination of the medicinal product by BPA, BADGE and BADGE derivatives can be precluded by using aluminium tubes with an internal lacquer with a low degree of unbound polymerisation residues. [ABSTRACT FROM AUTHOR]

The idea of joining by rolling emerged as an alternative to existing joining and assembling methods for lightweight frame structures, offering flexibility in manufacturing, low costs and simplicity in handling. The present paper deals with research work on joining of nodes in tubular aluminium structures by external rolling accompanied by applying glue. Special attention was paid to the node resistance and material behaviour when rolling by means of a one-roller burnisher and a multi-roller burnishing head. [ABSTRACT FROM AUTHOR]

Abstract: Cork is a complex natural cellular material with quite unknown or not well understood properties. It is available in the natural and in the agglomerate form and it is an ecological and very durable material. That is why it is used today as thermal and acoustic insulator, as a seal and as an energy-absorbing medium in flooring, shoes and packaging, among others. However, the application of agglomerate cork as filler inside structural thin-walled sections, in order to increase the energy absorption, has not been much explored. Dynamic experimental tests were carried out on empty and micro-agglomerate cork-filled tubes with 22 and 50mm in internal diameter and length , respectively, and numerical simulations were performed with the finite element method software LS-DYNATM, showing good agreement in terms of load–displacement curves and deformation patterns. Having validated the numerical model with experiments, the finite element model was used to undertake a systematic study of circular tubular structures impacted at 10m/s. The load-deformation characteristics, energy-absorption response and collapse mode transitions of empty and cork-filled aluminium tubes with varying diameters and thicknesses (t), lengths of 25, 300 and 350mm, but with constant slenderness ratios and were thus studied. Relevant comparisons were raised, showing that the slenderness ratios are very important parameters that globally govern the percentage increase in energy absorbed by tubular structures after cork-filling during an impact loading. [Copyright &y& Elsevier]