The Influence of Correct Transfer of Weld Information

ABSTRACT This study aims at identifying the causes for deviations between actual and theoretical weld weight. Previous performed studies have shown examples of up to 40% extra weld consumables used in some cases. One consequence is of course higher production cost but it can also give increased weight leading to higher fuel consumption and decreased payload. An interesting aspect is that generous margins on specific production measures dilute important feedback of process variation information preventing and prolonging structural root cause analysis. The causes for the observed deviations can heritage from several areas, both technical and within the information handling. The investigation shows that single components of the information structure and system, such as unsuitable demands as well as incapable evaluation methods, significantly influences the reliability of the entire manufacturing process. The common factor concerning when problems occur, seems to be the ability of correct information transfer between different functions in the organisation preventing the mismatch to appear in the interface. Suggestions for improving this situation include cross functional agreements as well as new measuring methods

Macroscopic neat single-wall carbon nanotube fibers

Measured and predicted properties of individual single wall carbon nanotubes (SWNT) suggest that bulk SWNT materials will exhibit a variety of exceptional properties. Due to the anisotropic nature of SWNTs, fibers are a logical candidate for these objects. The first ever macroscopic fibers, consisting entirely of SWNTs, were successfully produced and characterized. Nanotubes were dissolved at high concentrations (6--10 wt%) in 102% sulfuric acid. The SWNT/sulfuric acid system exhibited unique one-dimensional liquid crystalline phase behavior and interesting rheological characteristics. Fibers were extruded using a wet jet solution-spinning approach into diethyl ether without extensional drawing. Structural analysis showed them to be the highest aligned neat SWNT material produced to-date, with a revealing substructure of coagulated liquid crystalline domains. Additional characterization showed useful electrical and thermal properties and promising mechanical properties. Finally, the Spinning Bob Mixer (SBM), a custom laboratory mixer/extruder, was designed and successfully tested. Various features of the apparatus were demonstrated and shown to be valuable experimental tools for understanding the production of near SWNT fibers. This research has begun the exploration of an interesting and new field of nanotube science by providing a foundation of understanding and enabling future experiments

Strength characterization of suspended single-wall carbon nanotube ropes

Carbon nanotubes are expected to have incredible mechanical properties. Before they can be used intelligently in engineering applications, the capabilities and limitations of these properties must be well understood. This research measured the strain-to-failure of single-wall carbon nanotubes (SWNTs) by elastically straining suspended SWNT ropes using an atomic force microscope in lateral force mode. The ropes experienced multiple scanning cycles at high strains with no plastic deformation. The nanotube ropes were observed to strain as elastic strings, instead of as stiff beams. A maximum strain of 5.9 +/- 0.9% was observed, which led to a lower bound on the yield strength of 45 +/- 7 GPa for single-wall carbon nanotubes. These results are the first experimental evidence that supports the theoretical strain-to-failure of 5% for SWNTs. This research helps to establish single-wall nanotubes as a structural material by further quantifying their mechanical properties