SBIR-STTR Award

The goal of this proposal is to develop an efficient high-fidelity Abaqus-based toolset with significantly improved durability predictive capabilities for composite flexbeams using user-defined elements. The global analysis of the flexbeam will be carried out using Abaqus with the tapered regions meshed using 3D user-defined elements and the uniform region meshed with 1D user-defined beam elements. The effective properties of user-defined elements will be predicted by a micromechanical analysis formulated based on mechanics of structures genome. All the microstructural details including ply drop-offs and other defects will be explicitly modeled and the complete 3D stresses/strains will be accurately predicted at the ply level. Thermodynamically consistent continuum fatigue damage and cohesive zone models will be implemented in the micromechanical analyses for predicting multiaxial fatigue. The constitutive modeling of 3D user-defined elements will be implemented in SwiftComp, a general-purpose multiscale constitutive modeling code, and the constitutive modeling of 1D user-defined elements will be implemented in VABS, a general-purpose cross-sectional analysis. A mixed meshing scheme will be developed for easy finite element model creation in Abaqus. Success of this proposal will produce a practical solution for efficient yet accurate durability analysis of composite flexbeams.

Benefit:
This proposal will develop a practical tool for efficient and accurate durability analysis for tapered and curved composite structures with complex microstructures. The anticipated benefits are: Better strength and durability analysis for curved and tapered composite structures such as composite flexbeams. Significantly reduced time and cost used for design and redesign of complex composite structures. More insightful guidance for experiments in understanding the effects of ply drop-offs and other defects of composite flexbeams. Innovate multiscale modeling allows more explicit modeling of internal features and defects, easy handling of hybrid materials, and direct incorporation of new material models. The proposed Abaqus-based toolset can be acquired as an engineering tool for better design and analysis of composite flexbeams. The updated two existing commercial software codes, VABS and SwiftComp, can be used as a plugin for other finite element software for better constitutive modeling module for composite structures featuring complex microstructures. While the direct commercial application is durability analysis of composite flexbeams, the proposed work will also have many other potential commercial applications, including but not limited to, Composite helicopter rotor blades which is usually tapered. Ply drop-offs will happen along the spanwise direction. Composite wind turbine blades with cross sections varying significantly. Complex composite structures featuring non-uniform cross sections used in aerospace, automotive, and sports. Thick composite structures where ply-level stress and durability prediction is critical.

Keywords:
mechanics of structures genome, mechanics of structures genome, Delamination, SwiftComp, User-defined elements, VABS, Continuum Damage Mechanics, Multiaxial fatigue