Blast Mitigation Strategies for Sandwich Structures with Fiber-reinforced Facesheets
Abstract
We propose to develop lightweight blast mitigating sandwich structures with unidirectional fiberreinforced composite facesheets that provide the maximum resistance per unit areal density to blast loads representative of extreme in-air and underwater environments. We will develop a mathematical model of the problem, and the associated robust and verified computational algorithms for accurately ascertaining the damage/failure initiation and propagation in 3-dimensional deformations of structures, analyze fluid-structure interaction, and estimate the ultimate load. Furthermore, it will account for uncertainties in values of material and geometric parameters, and use design of experiment methodologies to compute the probability of the structure successfully sustaining a blast load. Possible blast mitigating strategies include employing functionally graded cores and facesheets, a thin epoxy layer on outer faces of a sandwich structure, a blast shield, and multiple cores. We will propose constitutive relations for damage evolution and propagation, failure criteria for marine sandwich structures, and degrade material properties depending upon the damage induced, water content and ageing. We will also address other challenging issues such as fluid-structure interaction, reflection and transmission of shock waves at the fluid-solid interface, coupled thermo-mechanical deformations, and the dependence of material properties upon the current temperature and the current strain-rate. We will validate the developed mathematical and computational models by comparing its predictions with results of physical tests available in the literature. Challenging Issues that will be addressed in the Proposed Work ? Develop mechanics-based mathematical and computational models of 3-dimensional finite transient deformations of doubly curved sandwich structures under extreme loadings ? Include in models damage/failure initiation and propagation, degradation of material properties based on the damage induced, moisture content and ageing, uncertainties in values of material and geometric parameters, dependence of material properties upon the strain-rate and the temperature ? Verify computational algorithms, and validate mathematical models by comparing its predictions with experimental findings of other investigators ? Develop science-based mathematical models of fluid-structure interaction (FSI), bubble formation and collapse, cavitation, and impact of bubbles with marine structures considering possible simultaneous interactions with water and air ? Consider thermal and mechanical loads of high intensity and short duration induced by explosions in water and in air realizing that time scales for thermal and mechanical problems are quite different ? Use thermodynamically consistent and materially objective 3-D failure theories ? Develop reduced-order models for sandwich structures and compare their predictions with those from analyses of 3-D problems ? Synthesize results to propose scaling laws and engineering models in the form of user-friendly packages for marine structure designers
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jul 26, 2018
- Source ID
- N000141812548
Entities
People
- Romesh Batra
Organizations
- Office of Naval Research
- United States Navy
- Virginia Tech