Influence of multiple load indentation on the mechanical and material behaviour of steel cone-cylinder under axial compression

The first set of test data on axial collapse of cone-cylinder assembly having multiple load indentation (MLI) and its accompanying numerical studies is presented in this paper. Two perfect and two imperfect steel cone-cylinders were prepared in pairs. The cone-cylinder models have the following geometric parameters: cone radius of 40 mm, cylinder radius of 70 mm,wall thickness of 0.5 mm and cone angle of 16.7°. Cone and cylinder part were combined using Metal Inert Gas (MIG) welding technique. Results show that the repeatability of the experiment was good (3% for the perfect and 7% for the imperfect). Also, numerical prediction tends to reproduce the test data with good accuracy. The error between both approches ranges from 1% to -8%. Furthermore, the influence of geometric parameters are also significant in determining the collapse load of this type of structure. Finally, the worst multiple load indentation (WMLI) was explored for steel cone-cylinders assembly using different number of load indentations. Results indicate that as the number of indents increases, the sensitivity of the cone-cylinder models to imperfection also increases. However, at different imperfection amplitude, A, two regions were observed; (i) the region where cone-cylinder with N = 8 is more sensitive (A < 1.5), and (ii) the region where N = 4 produce the worst imperfection (1.5 < A ≤ 1.68).

Faserschonende Carbonfaserproduktion durch innovatives Galetten-Oberflächen-Design - CarboGerd

While carbon fibres can easily absorb forces in the fibre direction, they are extremely sensitive to transverse stress due to their anisotropic material behaviour. During the manufacturing process, unavoidable transverse stresses are induced in the fibre by the drive and deflection godets, which can damage or destroy individual filaments of the roving. The demand for a surface that is gentle on the fibre is offset by the static friction required between the fibre and the godet in order to drive the fibre. The aim of the CarboGerd research project is therefore to develop and validate an optimal godet coating for fibre-protecting and quality-assuring carbon fibre production. For this purpose, both typical coatings (ceramic, Topocrom coatings) and unconventional solutions (elastomer, PACVD coatings) are being tribologically investigated on a laboratory scale and validated on a prototype system.