Manufacturing defect physics
Study how tow gaps, compaction pressure, cure cycles, squeeze flow, and resin bleed-out create resin-rich regions and non-uniform laminate morphology.
Osimulon research portfolio
Ahmad Ravangard
I am a Ph.D. candidate in Mechanical Engineering focused on applied mathematics, modeling, and simulation. My research combines numerical methods, computational mechanics, and experimental validation to study composite materials process modeling and progressive failure. I am especially interested in bridging simulation and experiment to predict material behavior and support reliable engineering design.
Research
Process-aware modeling for stronger composite structures.
My research connects automated fiber placement experiments with validated simulation to understand how manufacturing conditions become measurable defects, and how those defects can be reduced before they limit structural performance.
- Materials
- Carbon-fiber laminates, PEI/PPS veils, platelet-molded composites
- Measurements
- DIC, microscopy, tensile testing, rheometry, DMA, DSC
- Models
- FEA, CFD, cure kinetics, resin flow, progressive failure, machine learning
Research threads
Four connected research directions.
Waviness mitigation
Evaluate selective PEI/PPS thermoplastic veil placement in AFP layups, with reported reductions of up to 90% in out-of-plane fiber waviness while preserving mechanical performance.
Validated multiphysics simulation
Build FEA and CFD models for compaction, resin transport, cure kinetics, and failure, then calibrate them with DIC, microscopy, rheometry, and mechanical tests.
AI-assisted microstructure analysis
Use computer vision and machine learning to reconstruct composite microstructures and connect morphology with process history and material performance.
Tools I know
Methods, software, and lab capabilities.
Composite processing
01
Manufacturing physics
Experience with AFP-related process behavior, resin flow, and cure kinetics in composite laminates.
Simulation
02
Numerical modeling
Finite-element and flow simulation for compaction, resin transport, structural response, and process-performance studies.
Testing
03
Experimental characterization
Lab-based validation using full-field strain measurement, microscopy, thermal analysis, and mechanical testing.
Data and code
04
Scientific computing
Programming and data-driven analysis for simulation workflows, image analysis, and microstructure reconstruction.
Projects
Selected computational and composite studies.
Composite cure modeling
Bilamina Composite cure-induced deflection modeling
- Problem
- Predict cure-induced curvature and final deflection in a composite laminate.
- Method
- Model cure cycle temperature, degree of cure, glass-transition temperature, property evolution, thickness change, and curvature.
- Tools
- MATLAB, experimental temperature profiles, analytical laminate modeling.
- Result
- Predicted deflection compared with experimental measurements.
Kinetic theory
Integral-equation solution of the linearized BGK model for Couette flow
- Problem
- Describe rarefied Couette velocity fields from the linearized BGK model.
- Method
- Nondimensionalization, pure-shear simplification, and boundary conditions.
- Result
- Analytical reduction to an integral equation for velocity behavior.
Rarefied gas dynamics
Integral-equation analysis of Kramers flow using the linearized BGK model
- Problem
- Model rarefied gas motion over a flat plate with slip-flow behavior.
- Method
- Apply BGK linearization, boundary conditions, and asymptotic analysis.
- Result
- Integral-equation description of the Kramers velocity profile.
Numerical methods
RCIP for cornered integral equations
- Problem
- Solve singular Fredholm integral equations with corner singularities.
- Method
- Product Nystrom discretization and compressed inverse recursion.
- Result
- Stable high-accuracy integral-equation solution for BGKW Kramers flow.
Flow simulation
Coupled-pressure Navier-Stokes solver with multigrid Poisson acceleration
- Problem
- Accelerate incompressible lid-driven cavity flow simulation.
- Method
- Coupled pressure-velocity algorithm with multigrid Poisson solver.
- Result
- Reduced iteration counts and maintained benchmark accuracy.
LBM-MRT-MGM
Lattice Boltzmann MRT simulation of lid-driven cavity flow
- Problem
- Improve stability and efficiency for nearly incompressible cavity flow.
- Method
- Multiple-relaxation-time LBM with multigrid pressure correction.
- Result
- Fast, precise pressure-velocity solution for the cavity benchmark.
Publications
Papers, journals, and conference work.
Mitigating Out-of-Plane Fiber Waviness in AFP Laminates with Tow-Gaps via Selective Placement of Thermoplastic Veils
A. Ravangard, K. Celebi, S. G. Kravchenko, O. G. Kravchenko. Fibers, 13(11):145.
Effects of Biomass and Iron Catalyst on Yield of Plant-Based Graphitic Nanoplatelets
D. W. Mulqueen, A. Ravangard, J. D. Bhagatji, S. Kumar, O. G. Kravchenko. Materials Chemistry and Physics, 131629.
Compaction and Mechanical Performance of AFP Composites with Fiber Tow Gaps
A. Ravangard, O. Kravchenko. 24th International Conference on Composite Materials.
Reducing Out-of-Plane Fiber Waviness in AFP Laminate with Tow Gaps
A. Ravangard, O. Kravchenko. SAMPE Conference.
Mechanics of Resin Rich Regions Formation in AFP Preform with Staggered Fiber Tow Gaps
A. Ravangard, V. C. Jamora, J. D. Bhagatji, O. Kravchenko. Sixth International Symposium on Automated Composites Manufacturing.
Origin and Significance of Non-Uniform Morphology in AFP Composites
A. R. Ravangard, V. C. Jamora, J. D. Bhagatji, O. Kravchenko. American Society for Composites 38th Annual Technical Conference.
The Influence of Heat Transfer Due to Radiation from a Combustion Chamber
B. Razmjooei, A. R. Ravangard, L. Momayez, M. Ferchichi. Journal of Thermal Analysis and Calorimetry, 147(3):1901-1917.
Effects of Geometry on Simulation of Two-Phase Flow in Microchannel with Density and Viscosity Contrast
A. R. Ravangard, L. Momayez, M. Rashidi. Journal of Thermal Analysis and Calorimetry, 139(1):427-440.
A Numerical Investigation of Kenics Static Mixer as a Heat Exchanger in Separation and Segregation Process of Supercritical Carbon Dioxide
A. R. Ravangard, R. Kamali. Conference on Recent Advances in Aerospace and Associated Sciences.
Ph.D. in Mechanical Engineering, Old Dominion University, Norfolk, VA. M.Sc. in Aerospace Engineering, University of Tehran. B.Sc. in Mechanical Engineering, Islamic Azad University of Neyriz.
Programming, simulation, experimental characterization, composite manufacturing, numerical methods, machine learning, and technical communication.
Graduate teaching and research work across Mechanical and Aerospace Engineering, Mathematics and Statistics, Engineering Management, and NSF-funded research.
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