Ultrasonic welding is a very useful and simple welding process. It is suitable for establishing a joint between thin sheets and dissimilar metals with short preparation and finish work time . Some welding defects were detected due to less than optimal ultrasonic welding parameters. These defects were ruptures, surface colour change and unacceptable deformations. This article aims to identify these failures and their causes.
Zoltán Nyikes, Norbert Daruka and Tünde Anna Kovács
Unfortunately, people can’t live in peace in this century: many wars and terrorist attacks have been witnessed even within the last year. In the case of such attacks, both the people and the civil infrastructure is in danger [1-3]. The modern age (infrastructure) provides electrical networks and communication networks for the citizens. Without electricity and/or communications (e.g. the internet), urban life is paralysed. Explosions create heat and shock waves and their effects can potentially damage the wall and cables of a building as changes in the material structure occur. In this article, the authors introduce a blast load effect testing method in an empirical way. The metal microstructure deformation level is measurable by changes in resistance, because resistance is a physical property which depends on the crystal structure of the metal.
The goal of this work was to invent a high energy absorbing composite material. This composite needs to be able to attach on the building's surfaces and increase blast-resistance. In this innovation, the test samples were reinforced with aramidfiber, glass fiber and carbon fiber and tested by Charpy pendulum impact testing machine. During the tests, the aramid and glass fiber reinforced composites showed good resistance and high energy absorption against impact load.