Visualizatio of Composite Damage by Direct Energy
Abstract
The goal of this proposed research is to reveal the fundamental mechanisms for directed energy-induced damage under the surfaces of composite panels. Modern Navy ships are made of high percentage of composite structure components from hulls to deckhouses. The war"ships may be exposed to directed energy threats, such as laser, when carrying out their missions. Such exposures are expected to pro""duce structural damage in the composites, which compromises structural integrity. Depending on the intensity of the directed energy"" a composite material is exposed to, the surface layer or coating of the composite is excited to an ionized state (plasma). The asso""ciated sudden volume expansion during the phase transformation forms shock waves that propagate inside the composite structure, as w"ell as in the air. The passage of the shock waves damages the composite. The detailed damage sequence inside the composite material caused by the laser shock loading has never been recorded. To understand the dynamic damage mechanisms and the effects of a mitigat"ing layer, we propose to use our recently developed through-thickness, high-speed visualization techniques to record the damage sequ"ence. We will use high-speed x-ray phase contrast imaging (PCI) while exposing the composite specimens to directed energy at controlled intensities and durations. Effects of different surface mitigating layers will also be investigated. The research program will consist of six inter-related major portions: Year 1: (1) design and construct a portable laser-shock experimental setup that can be integrated into the synchrotron x-ray facility at the Advanced Photon Source (APS) at Argonne National Laboratory (ANL); and (2) determine proper experimental conditions under which the desired experiments canze the surface mitigating layer effects. Year 2: (3) experimentally record the laser-shock induced damage within the composite specimen under the effect of directed energy applied perpendicular to the x-ray beam; and (4) record the corresponding dynamic loading and temperature histories on the back surface of the specimens. Year 3: (5) Conduct the experiments over a range of laser intensity and duration conditions; and (6) investigate the surface mitigating layer effects.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Sep 01, 2017
- Source ID
- N000141712711
Entities
People
- Weinong Chen
Organizations
- Office of Naval Research
- United States Navy
- University of Virginia