Ingenieurwissenschaften und zugeordnete Tätigkeiten
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Three-dimensional vibration of a ring with a noncircular cross-section on an elastic foundation
(2018)
Probing joint strength and distortion in gas metal arc lap joining of aluminum and steel sheets
(2019)
Low-cost Locomotion Sensors
(2012)
A theoretical model for the tread slip and the effective rolling radius of the tyres in free rolling
(2017)
Conceptual ontology of prospective risk analysis in medical environments - the OPT-Model-Ontology
(2015)
German safety regulations and best practices to prevent accidents regarding the Gumi accident
(2013)
Arc attachments on aluminium during tungsten electrode positive polarity in TIG welding of aluminium
(2011)
In modem AC power sources, both balance and current of EP (tungsten electrode positive) and EN (tungsten electrode negative) can be readily adjusted. According to conventional assumptions the surface of aluminium workpieces is cleaned during EP but the tungsten electrode is more heated due to electron work function. During EN the tungsten electrode cools down and the workpiece is melted. Therefore, optimal settings of the power source mostly aim for maximal penetration and minimal electrode wear. This paper presents a study of arc attachments in TIG welding on aluminium. Two different arc attachments to the cathodic workpiece could be attested with only one of them actually cleaning the surface. The first one is a spot mode (highly dynamic) that attaches to the edges of oxide layers and cracks them. The second one is also a spot mode, but it attaches to weld pools. It does not clean the surface but heats the base material intensively. Both arc attachment modes compete against each other. As a result, the cleaning area narrows with wider weld pools due to an increasing attachment to the weld pool during EP. The influences on the arc attachment to the aluminium cathode as well as the contradictions in present literature are discussed. Possible adjustments of the AC balance for optimized processes are proposed.
There are two aims for the second part of this paper: verifying the theory presented in the first part through parameter variation and comparison between simulation and experiment, and to study the effect of the belt structure on the cornering properties of radial tyres. Research has been carried out with a passenger car radial tyre and two different kinds of truck or bus radial tyres using both simulation and experiment. This second part of the paper shows that belt structure plays an important role in the generation of tyre forces and moments in addition to the effects of the tread stiffness and friction coefficients. The theory and method presented in this paper opens a new robust way to predict the tyre forces and moments from the tyre design and provides a reliable model for a generation mechanism.