The analysis of research results concerning heat release rates of ship materials with regard to dynamic parameters of the research station
The analysis of research results concerning heat release rates of ship materials with regard to dynamic parameters of the research station Based on the results of author's research it was stated that significant differences between heat release rates measured according to ISO 5660-1 and FTP Code Part 5 (Res. A. 653 (16)) are not caused by measurement uncertainties. A basic factor determining the lack of correlation is treating the heat release rate in the category of static measurements in the normalized measurement methods. Taking into account dynamic parameters of the test station allowed the coincidence rate (reproducibility and correlation) of the results of heat release rates measured using different methods to be improved, without changing test stations and procedures. Author's research performed on 42 materials has revealed that the relative dynamic errors of the heat release rate measurements are significant (2%÷120%). The average value of these changes for the tested group of materials was equal to 39%.
An evaluation of heat release criteria in reaction-to-fire tests
A theoretical approach is developed for evaluating quantitatively the heat evolved during a reaction-to-fire test. This involves determining the transfer function from two head balance equations, one concerning the walls and the other the air in the test box. A comparison between this theoretical approach and the empirical ‘area under the curve’ method has been made for 34 tests on electrical cables. It is shown that the empirical method is unacceptable.
Joint strength of aluminum ultrasonic soldered under liquidus temperature of Sn–Zn hypereutectic solder
Abstract In order to obtain high-strength aluminum joints, ultrasonic soldering of 1070 aluminum was conducted under liquidus temperature of Sn–Zn hypereutectic solder. A device for ultrasonic soldering was assembled, which propagated ultrasonic vibrations in a direction perpendicular to joining surfaces. This device joined 1070-Al using quasi-melting Sn–Zn hypereutectic solder without using any artificial spacers. The strength of the solder joints was evaluated by tensile tests. The optimum joining conditions were determined, and the effects of solder compositions and soldering temperature on the joint strength and the solder layer thickness were examined. In this ultrasonic soldering process, the highest tensile strength was obtained for the solder joints fabricated at 220 °C for the Sn–23Zn and Sn–40Zn solder compositions. The joint strength was equivalent to that of 1070-Al heat treated at 220 °C. The sound joints were obtained at 300 °C using Sn–82Zn solder, the liquid phase volume fraction of which was theoretically only 0.24. The present work also revealed that the thickness of retained solder layer in the joint after ultrasonic soldering could be estimated. Accordingly, ultrasonic soldering under the liquidus temperature of Sn–Zn hypereutectic solder could be a spacer-free soldering method to obtain high-strength aluminum joints.