University of Tennessee, Knoxville (UTK) doctoral student Will Ferrell and Dr. Stephanie TerMaath, professor of mechanical, aerospace and biomedical engineering, presented their updated research on composite parts fabricated through polymer additive manufacturing as part of a collaboration they have been working on with Naval Surface Warfare Center, Carderock Division (NSWCCD) on Jan. 22.
For the past few years, the UTK team has been working alongside different branches at Carderock to better understand how printing parameters, such as nozzle temperatures, cooling, sample size and print time, affect the mechanical properties of the material. The ultimate goal is to qualify components made from these materials for use in shipboard applications.
This three-year project is part of the Naval Engineering Education Consortium (NEEC), which is a program that provides funding for relevant research at academic institutions and provides opportunities for students to participate in hands-on research during the academic year to develop their technical abilities. The educational objective is to prepare students for careers with the Navy while accomplishing the technical objective. This program provides the students with daily hands-on technical training, interaction with Navy personnel and recruiters and helps them to develop a diverse, multi-disciplinary workforce. Currently, there are three NEEC projects funded at Carderock, overseen by STEM and Outreach Program Director Charlotte George.
The technical objective for the UTK NEEC contract, which ends in May, is to explore and demonstrate the potential of an integrated experimental and computational approach to the qualification process of composite parts fabricated with embedded fibers.
These UTK students have worked with Carderock employees in the Integrated Manufacturing and Project Management Office, as well as the Advanced Materials and Structures Branch, as TerMaath also had an Office of Naval Research Young Investigator Project (ONR YIP) on composite patches. Materials engineer Dr. Maureen Foley from Carderock is the technical point of contact for the NEEC with UTK.
Originally working through the building-block approach through comprehensive experimental testing, the UTK team found this to be cost prohibitive due to the sheer number of tests needed. They instead have been developing an integrated and automated simulation environment to supplement physical testing.
“We are developing a simulation environment for additive manufacturing and composites to predict material behavior using multi-scale analysis. The goal is to evaluate material combinations and process specifications prior to comprehensive testing. Using this approach, we no longer have to test everything, and instead, we can rapidly investigate new and emerging materials and test only the most promising for a given application. It would be the ideal case that someone could go into a database and look at all of the material choices, select the constituents and configuration, perform a multi-scale structural analysis through modeling and simulation, run some tests to evaluate reliability and optimize the design and then in the end, come out with a new, reliable part,” TerMaath said.
With this computational environment, the team would be able to test material properties, boundary conditions, probabilistic distributions, loading conditions, uncertainty and data quality information, loading conditions and analytical models. Through multi-scale analysis, they would also have the opportunity to recommend guidelines and extrusion settings. Allowing the user to first select their constituents and configuration has the benefit of allowing them to rapidly explore many different combinations. They would then be able to perform a multi-scale structural analysis, varying the fidelity at each scale and investigating multiple loading conditions. Lastly, the probabilistic capabilities would allow for the evaluation of the material’s reliability and design optimization to minimize the cost and weight of the material and maximize performance.
While they were at Carderock, the UTK students leveraged the ONR YIP grant that TerMaath had in the area of composite patches to extend the collaborative activities that could take place. The students have worked alongside aerospace engineer Daniel Hart in Carderock’s Structural Composites Branch in the lab laying down the materials to create composite patches. It takes between 12 and 14 hours for a patch to be ready to be tested. Once these patches are created, they are put through tension and compression tests to evaluate how much the patch elongates and how strong it is before it breaks.
In the classification stage, they have concluded that specimen size affects strength and repeatability. Specific geometry and specification to the number of beads required in cross sectioning these parts may be pertinent to achieve geometry independent properties. They also found that matching the specimen size and processing conditions is necessary for accurate qualification. In the processing stage, they concluded that the layer time and process control can lead to stronger prints and less variable prints. Lastly, in the methodologies, they concluded that sequential prints could produce slightly weaker prints, but with increased repeatability and more prints per unit; cutting methods need to be reported for consistency; and printer variability exists and should be included in the variability processes where machines need to be qualified as well.
Ongoing work includes predicting fracture behavior of a demonstration part; informing finite element models using peridynamics results; and quantifying uncertainty using non-deterministic analysis on uncertain material parameters, such as fiber length, density and orientation, as well as air voids and dimensional variation.
| Date Taken: | 01.23.2019 |
| Date Posted: | 02.12.2019 11:23 |
| Story ID: | 310421 |
| Location: | WEST BETHESDA, MARYLAND, US |
| Web Views: | 107 |
| Downloads: | 0 |
This work, University students update Carderock on their NEEC project, by Brooke Marquardt, identified by DVIDS, must comply with the restrictions shown on https://www.dvidshub.net/about/copyright.
No keywords found.
