Prediction of High-Velocity Droplet Damage Using Peridynamic Approaches
Abstract
Deployed high-speed aerospace vehicles will experience adverse weather encounters, especially impact by water droplets, which may result in damage to the surface. The damage morphology and extent depend on the shape of the droplet at the time of impact. The shaperesults from the interaction between the droplet and the bow shock ahead of the vehicle. The thermodynamic conditions within the shock region, droplet initial size, impact velocity, angle of impact, and other conditions affect the damage, which may be significant. Smaller particulates at high altitudes may also be a major source of impact damage. Particulates as small as 10 µm are predicted to generate damage with a direct effect on the aerodynamics of the vehicle. To develop a fundamental understanding of impact damage and the resulting material failure and erosion due to weather encounters at hypersonic flight conditions, the important elements of the physics of the problem must be included in the computational simulation approaches. This project aims to develop a general-purpose computational analysis capability for impact damage due to atmospheric encounters under hypersonic flow conditions. The proposed work will utilize and develop methodologies within the framework of peridynamics. Peridynamics (PD) is a generalization of the standard equations of continuum mechanics compatible with the mathematical discontinuities in growing cracks. This study will use a meshless discretization of the peridynamic equations. This approach offers a combination of advantages for this application: (1) It avoidsmesh tangling and distortion since it is meshless. (2) It allows arbitrary changes in the connectivity of the nodes, enabling the raindrop to disintegrate and target material to be ejected. (3) It is designed to model the propagation of any number of mutually interacting dynamic fractures without additional equations or the use of a smeared crack damage model. (4) It allows all the standard shock physics equations, including thermodynamics and equations of state. (5) Any material model from a finite element code or hydrocode can be included directly in a peridynamic code. For the present project, we will use Sandia#s Emu code, which we have extensive experience with and a working relationship with the Sandia developer.Based on the foregoing, we propose to use the peridynamic approach to model the key components of the high-speed raindrop impact on the friable targets problem. The peridynamic approach will predict the droplet impact damage and subsequent material ejection. For the predictions of droplet deformation and/or demise while in bow shock, disturbance of the flow field due to multiple droplets and/or ejecta, and the aerothermal and fluid performance of the modified/damaged surface post-impact, we will enlist a two-phase computational fluid dynamics (CFD) approach from Prof. Christoph Brehm (Maryland). This project will deliver a general purpose, high-fidelity, 3-D, coupled PD-CFD simulation tool for high-speed droplet impact events capable of addressing all the key physics of the problem. The project will demonstrate the capabilities of the new approach by considering Navy-relevant case studies involving multiple impacts, responses of target materials (ceramics, high-temperaturecomposites) with and without protective coatings, debris shielding, post-impact surface behavior under extreme flow and aerothermodynamic conditions.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Apr 11, 2024
- Source ID
- N000142412268
Entities
People
- Ibrahim Guven
Organizations
- Office of Naval Research
- United States Navy
- Virginia Commonwealth University