Search Results

The disk spring offers the potential of significant weight savings when designed with continuous fiber reinforced composite materials. The internal stresses in a disk spring are ideally suited for composite material application due to their superior resistance to in-plane and bending stresses. In this study, a composite laminate disk spring is designed, analyzed and fabricated to take advantage of the low specific strength and weight and high damage tolerance of composite laminates. The design of the disk composite spring considers effects of the laminate stacking sequence and the geometric variables on the disk spring's mechanical performance. A continuum damage finite element analysis approach is used to understand the damage initiation and evolution as a function of applied load. Experimental analysis and a progressive damage analysis based on virtual crack closure technique are performed to evaluate the damage tolerance of the disk spring under fatigue loadings.

Additive Manufacturing of Aerospace Composite Structures: Fabrication and Reliability introduces the reader to the current state of technologies involved in processing and design of polymer-reinforced fiber composites using additive manufacturing's automated fiber placement methods, through ten seminal SAE International papers. Currently, the material layup strategy in terms of process selection and manufacturability is usually not prioritized in the design phase. Engineers do not have a good way to see how their design choices can affect the manufacturing process beyond their initial structural-level considerations. The result is typically a large amount of experimental testing necessary to qualify the materials and structures typified in the classical building-block approach. Such an environment makes mistakes difficult to solve and, should redesign be required, obtaining reliable information is hard to piece together.

Additive manufacturing (AM) for space exploration has become a growing opportunity as long-range space missions evolve. In partnership with the National Space Grant Foundation and NASA, students from the University of Wisconsin-Milwaukee participated in the 2014-15 X-Hab Academic Innovation Challenge, with participants tasked with developing new AM solutions that would be recyclable with minimal loss in mechanical properties. The teams investigated materials, characterization, testing, modeling, and tool development, including the ability to employ reusable carbon-fiber tension ties. The tools developed show that it is possible to employ thermoplastic polymer materials fabricated using AM together with reusable and flexible high-performance carbon-fiber-based composite ties. The AM-printed part is completely recyclable. The carbon-fiber composite ties are repurposed into new structural configurations without loss in properties.