Stress Analysis, Fixture Design for MSA Pathfinder and Pin Tool Analysis Using Conventional Friction Stir Welding
Student: Daniel H. Hernandez Jr.
University of Texas at El Paso
Major: Mechanical Engineering
Degree Level: Bachelor of Science
Internship Site: NASA Marshall Space Flight Center, Huntsville, Alabama
Mentors: Shane Brooke, Jon Street and Carolyn Russell
Abstract: Friction Stir Welding is a process in which different factors such as travel speed, rotational speed (RPM), and plunge force play a key role in creating a successful weld. Friction is created between two panels by a shoulder and pin. This friction causes the material at the abutting edge of two panels to plasticize (plastically deformed “70 percent of melting point”- taffy consistency), allowing for the material to be stirred and welded. This project will consist of two separate but equally important tasks. First, is to analyze the nugget shape and material flow characteristics of conventionally friction stir welded (C-FSW) panels with different pin tool designs. Analyzing the nugget shape and stirring of the weld through optical microscopy will aid in understanding how these flats will affect a weld. There are six different pin tool designs for this project: a standard C-FSW pin without machined flat edges (baseline), and five others with flats ranging from 1 to 5. The panels to be welded are aluminum 2219 to aluminum 2219. This project will aid in understanding the differences and similarities between each of the pins. This work will ultimately aid in determining which pin design provides the optimum weld schedule and characteristics. Second, is to support fixture design, stress analysis (FEA), and procurement for the Multi-purpose Crew Vehicle Stage Adapter (MSA) pathfinder cone to adapter ring weld for the Space Launch System (SLS). (The research was co-authored by Daniel H. Hernandez Jr. and Elvis Boves).
* If you are having trouble viewing this poster, please download it as a pdf.