New Approach for Modelling of the Welding Processes
The applying of new technologies is connected with considerable outlays to receive the optimal welding regimes, metallographic research of welding seams, joint quality control and other facilities, which can be considerable lowered, using modelling of the welding processes. We propose to use new approach for modelling – analogue modelling, which is based on process investigation, using logical functions. Some practical applying examples of the analogue modelling are offered in this paper. The analogue model of the heat input during resistance welding of wires with coating is described in detail. Using analogue modelling we can solve direct problems of thermal conductivity, it mean that we can predict temperature field, obtained as a result of influence of welding source of heat. The effectiveness of analogue modelling using is proven.
RESEARCH ON THE SURFACE COATINGS INFLUENCE ON FORMATION MECHANISM OF THE RESISTANCE WELDS
The goal of the work is the research of formation mechanism of the spot resistance welds in the case of copper wires with nickel and tin coatings. The existing approaches for investigation of the formation mechanisms of welds of wires with and without coatings are analysed. A new approach for modeling of welding joint formation is offered. The analog model of the heat input during resistance welding of
Measuring Sheet Resistances of Dielectrics Using Co‐Planar Hydrogel Electrochemical Cells with Practical Applications to Characterize the Protective Quality of Paints on Sculptures
Electrical properties of thin dielectric films at the solid-liquid phase boundary are an important performance characteristic of many devices, coatings and sensors. In this paper, co-polymeric hydrogels of polyacrylic acid co-sulfonic acid, swollen with a salt solution to act as the solid electrolyte, were used to assess interfaces using electrochemical impedance spectroscopy (EIS) in a co-planar geometry. Silane-modified glasses were characterized by the co-planar hydrogel EIS cell and found to be distinguishable based on their surface monolayer chemistry. EIS measurements were also made on primed and painted metal substrates, using both test panels and an outdoor sculpture, Tony Smith's Stinger. The panels were then exposed to accelerated and outdoor weathering and showed degradation on the surface paint layers, which was observable electrochemically using EIS and confirmed visually by SEM. Electrochemical spectral features were compared between data from a standard paint-test cell versus this co-planar hydrogel cell; both cell types were able to measure coating capacitance, providing useful information about the condition of the bulk coating. Yet, sheet resistance (Rs) was a spectral feature seen only by the co-planar hydrogel cell. Thus, it can be concluded that the use of such co-planar hydrogel cells can provide an earlier warning sign to coating degradation and such cells provide a new type of spectral information that is not assessable by the standard geometry.