Dynamic characterization of metamaterials based on selective emptyin
Ismael Rodriguez Sesma
Project Timeline
Jan 2022 - Jun-2023
OVERVIEW
This project investigated how additive manufacturing (3D printing) can enable locally resonant “metamaterial” structures for passive vibration suppression. I first established a non-destructive workflow to characterize material properties of printed PLA parts—especially Young’s modulus—using vibration testing and an ISO-based methodology applied to beam antiresonance frequencies. With those material parameters, I built finite element (FEM) models in MATLAB from scratch for free–free beams and free–free–free–free plates, then validated them against analytical plate/beam solutions.
The core design outcome was a family of 3D-printed plates embedding an array of tuned mass dampers (TMDs) created via selective emptying: 20 compliant resonators integrated into the plate to attenuate a targeted bending “breathing” mode. Finally, I executed an experimental campaign (shaker + accelerometers), diagnosed real-world boundary-condition effects (thread stiffness + pendulum modes), estimated damping from test data, and refined the numerical model to better match measured frequency responses
HighlightS
- Designed and validated a non-destructive elastic modulus characterization method for printed PLA using vibration tests on beam specimens (ISO 16940 approach adapted to this application), then used the measured modulus to feed plate simulations
- Built a custom MATLAB FEM solver (element formulation, meshing, assembly, frequency response solution) for free–free beams (beam elements) and free–free–free–free plates (Mindlin–Reissner plate elements + Gauss–Legendre integration)
- Executed a large experimental campaign: defined 50 beam configurations, printed 3 repeats each (≈150 tests) to quantify repeatability and sensitivity to print parameters (orientation, raster angle, infill, layer height, infill pattern)
- Designed embedded TMD geometries (cantilever “tab” + tip mass) and performed parametric tuning to hit target frequencies; produced two tuned-plate variants to account for the fact that “hole patterns” shift the parent plate’s modal frequencies
- Demonstrated targeted resonance attenuation experimentally: the tuned plates showed suppression at the objective frequencies (e.g., ~250 Hz and ~180 Hz cases), validating the locally resonant concept in physical prototypes
- Closed the loop between theory and test by:
- Identifying low-frequency artifacts from “FFFF in 1g” suspension (pendulum-like motion and thread stiffness)
- Adding equivalent stiffness/mass effects into the FEM model
- Estimating damping via the half-power bandwidth method and implementing proportional damping for improved FRF matching
SKILLS
Structural dynamics & vibrationModeling & simulation (FEM)Experimental test engineeringAdditive manufacturing for engineering prototypesMetamaterials / passive vibration controlEngineering communication
External Links
Ismael Rodriguez Sesma
Aerospace Engineer & Systems Designer
I'm an aerospace engineer pursuing dual MSc degrees at Georgia Tech and Universidad Politécnica de Madrid, specializing in multidisciplinary simulation and model-based systems engineering. With experience in aircraft design, propulsion systems, and structural analysis, I develop integrated simulation models using MATLAB, Python, and ANSYS to validate complex mechanical and thermal systems. My background spans from theoretical aerodynamics to practical design engineering, with proven expertise in reducing prototype cycles and improving design traceability through MBSE principles.
I'm an aerospace engineer pursuing dual MSc degrees at Georgia Tech and Universidad Politécnica de Madrid, specializing in multidisciplinary simulation and model-based systems engineering. With experience in aircraft design, propulsion systems, and structural analysis, I develop integrated simulation models using MATLAB, Python, and ANSYS to validate complex mechanical and thermal systems. My background spans from theoretical aerodynamics to practical design engineering, with proven expertise in reducing prototype cycles and improving design traceability through MBSE principles.