Skip to Main Content
 

Global Search Box

 
 
 
 

ETD Abstract Container

Abstract Header

Lightweight Aluminum Structures with Embedded Reinforcement Fibers via Ultrasonic Additive Manufacturing

Scheidt, Matthew

Abstract Details

2016, Master of Science, Ohio State University, Mechanical Engineering.
Ultrasonic additive manufacturing (UAM) is a state of the art, low temperature, solid-state metal welding 3-D printing process. Metal foil, referred to as a tape, approximately 0.006 in. (0.1524 mm) thick, is fed through an automated feeder, and is welded, through the use of pressure and 20 kHz ultrasonic vibrations, to a base plate and/or additional foil, stacking, to build up material. The welder is integrated within a Computer Numerically Controlled (CNC) framework that uses standard machining operations to remove materials to create complex geometries, before and/or after each weld pass. With relatively low welding temperatures, thermally sensitive materials can be embedded, allowing for integrated sensing and thermal expansion control. Additionally, materials can be embedded that allow for the strengthening and lightweighting of structures. This thesis focuses on two aspects related to increasing the strength along the axis that tapes are welded, otherwise known as the weld direction. The primary focus of this research is to achieve lightweighting by embedding high strength/low density materials within an aluminum matrix using UAM. This method of creating composites revealed a reduction in strength of the metal matrix due to the UAM process. Investigating the cause of this reduction in strength became the second focus area of this thesis. The first aspect of this research explores different lightweight and strong materials to integrate within a welded area to increase axial strength. The embedded materials explored include metal wires, ceramic fibers, thermoplastics, thermoset polymers and MetPreg, a commercial off the shelf metal matrix composite. Additionally, Al 6061-H18 tape was welded to 0.9 mm 5052-O baseplate, becoming the metal matrix for the embedded materials. Normalizing for density, all added materials increase the specific strength of the metal matrix alone. A key finding is the significance of the interface strength between the fibers and the matrix when channels are used to integrate strengthening materials into a structure. The second aspect of this research is a design of experiments study to explore the effects of weld parameters on the strength, in the weld direction, of UAM created parts in order to understand the cause for the reduction in strength compared to pre-welded materials. Weld force, weld speed, and weld amplitude are varied across the parameters used for previous design of experiment studies, using both 1 kW and 9 kW welding systems. This study shows statistically significant correlations with weld force, weld speed and weld amplitude on the tensile strength of manufactured parts in the weld direction. Additionally, weld force, speed and amplitude are shown to significantly correlate with the failure strain in tension. A new weld energy density term is introduced that correlates with X-tensile stress-strain behavior of UAM constructed tensile coupons. The strongest and weakest samples tested show vastly different weld quality suggesting increasing weld direction strength is negatively correlated with gapless welds.
Marcelo Dapino (Advisor)
Farhang Pourboghrat (Committee Member)
188 p.

Recommended Citations

Citations

  • Scheidt, M. (2016). Lightweight Aluminum Structures with Embedded Reinforcement Fibers via Ultrasonic Additive Manufacturing [Master's thesis, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1469112453

    APA Style (7th edition)

  • Scheidt, Matthew. Lightweight Aluminum Structures with Embedded Reinforcement Fibers via Ultrasonic Additive Manufacturing. 2016. Ohio State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1469112453.

    MLA Style (8th edition)

  • Scheidt, Matthew. "Lightweight Aluminum Structures with Embedded Reinforcement Fibers via Ultrasonic Additive Manufacturing." Master's thesis, Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1469112453

    Chicago Manual of Style (17th edition)