| Popis: |
Titanium alloys, especially Ti-6Al-4V, have been widely used in the aerospace industry due to their high specific strength, high heat-resistant, and high corrosion-resistant properties. This alloy is used in current airframe applications for medium-sized forgings in high load transfer components such as the engine pylon and undercarriage support fittings on the wing, adopting the friction stir spot welding to reduce the use of bolts on structural components. Based on finite element analysis, the three-dimensional model, described in this work, combines the mechanical action of the shoulder and the thermomechanical effect of the welded. Johnson–Cook model is used as a basis of constitutive law in which the yield strength is affected by the temperature and strain rate for the Ti-6Al-4V alloy. The sheet of 2.3 mm thickness were friction stir spot welded using a tool with a convex scrolled shoulder made of a polycrystalline cubic boron nitride (PCBN). The parameter processes employed in this study are rotational speed, plunge speed, and dwell time and plunge depths. The material flow was also numerically simulated using the DEFORM-3D FE software. Results indicated with the incremental penetration of the pin; material from below the pin was displaced upward along the sides of the pin. FE results were verified by experimental results. |
