Theses and Dissertations

Issuing Body

Mississippi State University

Advisor

Lacy, Thomas E. Jr.

Committee Member

Kundu, Santanu

Committee Member

Koenig, Keith

Date of Degree

12-1-2018

Document Type

Graduate Thesis - Open Access

Major

Aerospace Engineering

Degree Name

Master of Science

College

James Worth Bagley College of Engineering

Department

Department of Aerospace Engineering

Abstract

Energy dissipation during penetration is an important consideration in materials selection for lightweight armoring to protect against hypervelocity impacts (HVIs). Impact-induced glass transition in polymeric materials has been observed to increase energy dissipation during penetration. Incorporating unconventional armor materials like polymers could improve performance in these types of applications. A series of HVIs was performed, with impact velocities over the range of 2-7 km/s, on samples of ultra-high molecular weight polyethylene and poly(methyl methacrylate). A relationship between back face debris cloud velocity and impact velocity was developed for each material. Damage zone sizes were compared, offering insights into the effects of molecular architecture on stress delocalization and energy dissipation during hypervelocity perforation. Thermal analysis of the two material systems provides quasi-static glass transition temperatures, as well as melting and crystallization temperatures. The apparent failure mechanisms, in conjunction with thermal analysis, were used to explain the relative performance of each material.

URI

https://hdl.handle.net/11668/20909

Comments

hypervelocity||impact||polymer||perforation||viscoelasticity||strain rate

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