About

Dr. Andrew Lee is an Assistant Professor in the Department of Mechanical and Aerospace Engineering at NC State University. His research focuses on leveraging the actuation and sensing capabilities of active materials to develop deployable and reconfigurable structures that are multifunctional. The aim of his work is to design structural systems and architectures capable of adapting to dynamic environments through self-shaping and monitoring. He is particularly interested in lightweight space structures, thin-ply composite materials, dynamical and vibrational systems, and elastic instabilities. Dr. Lee received his B.S.E., M.S.E., and Ph.D. in Aerospace Engineering from the University of Michigan. Prior to joining NC State, he was a postdoctoral scholar at the Graduate Aerospace Laboratories at the California Institute of Technology. He has also worked as a mechanical engineer at Raytheon Technologies. His contributions include research on continuum modeling for deployable space trusses, integration of origami-inspired folding into deployable composite shells, optical sensing of deployment dynamics in composite shell structures, and the characterization of nonlinear vibrations in composite tape spring hinges, among others.

Research topics

• Computer Science
• Mechanics
• Physics
• Mathematics
• Materials science
• Artificial Intelligence
• Optoelectronics
• Structural engineering
• Engineering
• Geometry
• Acoustics

Selected publications

• Extension of cross-well bandwidths for bistable piezoelectric plate oscillators

  Journal of Intelligent Material Systems and Structures · 2026-04-13

  article1st authorCorresponding

  Snap-through dynamics between the two potential wells of bistable oscillators are exhibited over a wide frequency range which narrows with decreasing harmonic excitation amplitudes until disappearing at a critical forcing level. However, for efficient conversion from vibrational to electrical energy in harvesting applications, the bistable oscillator must retain its favorable broadband cross-well response while the input excitation is minimized. To maintain effectiveness at low forcing levels, an actuation approach is proposed where external perturbations are used to extend the oscillator’s cross-well bandwidths by switching from co-existing low to high energy attractors. By utilizing Macro Fiber Composites (MFC) in a [ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"> <mml:mrow> <mml:msup> <mml:mrow> <mml:mn>0</mml:mn> </mml:mrow> <mml:mrow> <mml:mi>MFC</mml:mi> </mml:mrow> </mml:msup> </mml:mrow> </mml:math> / <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"> <mml:mrow> <mml:msup> <mml:mrow> <mml:mn>90</mml:mn> </mml:mrow> <mml:mrow> <mml:mi>MFC</mml:mi> </mml:mrow> </mml:msup> </mml:mrow> </mml:math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mrow> <mml:mo>]</mml:mo> </mml:mrow> <mml:mrow> <mml:mi>T</mml:mi> </mml:mrow> </mml:msub> </mml:mrow> </mml:math> bistable piezoelectric laminate, the application of rectangular voltage pulse signals are cycled through different response phases to continuously alter the basins of attraction until the desired cross-well orbit is sustained at each frequency. The pulse magnitude is where the system exhibits limit point behavior and the resulting snap through actuation mechanism brings consistency between perturbation trials. A multi degree of freedom electromechanical model that captures the stable shapes and cross-well dynamics and finite element analysis in Abaqus/Standard demonstrate the efficacy of the perturbation method. The model is then employed to significantly increase the bandwidths inducing cross-well oscillations.

  PublisherDOI

• Continuum Modeling for Deployable Space Trusses with Collapsible Tubular Masts

  2026-01-08

  article

  An equivalent continuum model is developed for 2D and 3D square deployable space trusses consisting of composite Collapsible Tubular Mast (CTM) members. The repetitive nature of these structures allow for the utilization of single unit cell geometries in deriving effective stiffness and mass properties through energy equivalence, which are then compatible with continuous structural analysis such as standard beam theory. This provides an efficient method of approximating the global structural performance over a large parameter space for design optimization. Finite element analysis (FEA) in Abaqus/Standard models the CTM members as beam elements with direction dependent stiffnesses. End moment releases on the beam elements simulate how the CTM members are joined together by bonding the ends in a flattened state. FEA is used validate the analytical natural frequencies of 2D and 3D square truss configurations including bending, longitudinal, torsional, and warping-shear vibration modes. It also characterizes how the 3D square face arrangement influences the vibration modes based on whether the diagonal members from adjacent faces share common joints. An FEA validated parametric analysis is then conducted to examine how variations in unit cell geometries and truss patterns influence the equivalent continuum vibration modes for 2D and 3D square trusses.

  PublisherDOI

• Integration of Origami-Inspired Folding into Deployable Composite Shells

  2026-01-08

  articleSenior author

  This work presents an origami-inspired deployable composite shell structure that allows crease-folded packaging while retaining self-deployability enabled by the shell curvature. The structure incorporates crease lines by locally dropping plies so that only a single 45 degree plainweave carbon fiber/epoxy layer remains as a flexible hinge. The crease is supplemented by thin polyurethane tape to accommodate near-flattened folding. To evaluate the folding and unfolding behaviors, column bending tests are performed on an origami tape spring with a central crease line and compared against an uncreased control tape spring and a creased flat coupon. The origami tape spring shows the highest axial force and bending moment in the folded state, driven by the large crease thickness and curvature effects, but displays a milder snap-through response during quasi-static unfolding. Dynamic deployment experiments reveal that the origami tape spring reliably self-unfolds, but retains a slower and more controlled deployment than the control tape spring. Importantly, peak-to-peak accelerations induced by shock events at the end of deployment is reduced by 74–79\%, demonstrating significant mitigation. Overall, integrating shell curvature with origami folding enables composite space structures that can be stowed in a near-flattened state, be self-deployable, and scalable in design with more complex fold patterns.

  PublisherDOI

• Corrigendum to “Deployment of bistable composite tape springs with non-uniform curvatures” [Compos. Struct. 367 (2025) 119235]

  Composite Structures · 2025-11-01

  articleSenior authorCorresponding
  PublisherDOI

• Optimal Cable-Stayed Forms for Pretensioned Space Structures

  AIAA Journal · 2025-04-15

  article

  To improve the deployed stiffness and mass efficiency of pretensioned spacecraft structures, the efficacy of cable-stayed configurations is analyzed in this paper. The reference structure is a deployable array wing that supports a series of radio frequency panels for space-based antenna applications, and it is designed to be z-folded under stowage. Due to the significant mass of the panels and the large span of the array wing, the entire structure is susceptible to low-frequency excitation. Lightweight pretensioned cables that elastically support and stiffen the array along its span are found to drastically raise its fundamental frequency and critical buckling load. An analytical model that is validated by finite element simulations is used to predict the vibration and buckling modes of the constituent structures for both the reference and cable-stayed architectures. A parametric analysis then optimizes the cross section of the load-bearing members, cable attachment points, and the number of cables to maximize the fundamental frequency for the structural systems. These optimal cable-stayed forms are compared against the reference design, and their effectiveness is demonstrated with a 157% and 255% increase in fundamental frequency for one and two cables, respectively.

  PublisherDOI

• Uncoiling deployment of thin-shell composite booms with piezoelectric actuation

  Smart Materials and Structures · 2025-01-06 · 7 citations

  articleOpen accessSenior author

  Abstract The efficacy of using piezoelectric actuators to initiate the dynamic deployment of bistable composite tape springs is evaluated in this paper. Ultra-thin composite booms such as tape springs and their cross-sectional variants have seen increased popularity in spacecraft structures due to enabling the precise deployment of flexible solar arrays, sails, reflectors, and antennas. They can elastically transition between the deployed ‘extended’ position and the stowed ‘coiled’ position while retaining superior stiffness, thermal properties, mass efficiency, and compactness when compared to thin-shelled metal booms and rigid articulated columns. Bistability in the coiled and extended states allows the boom to exhibit more controllable self-deployment and become reconfigurable, which could allow spacecraft to relocate, redeploy, and adapt to changing environmental conditions or mission objectives. Deployment systems commonly include motors and mechanical restraints that significantly contribute to mechanical complexity and spacecraft weight. Since bistable booms do not rely on elastic instability of packaging to initiate motion, a non-intrusive and lightweight actuation mechanism is needed to trigger deployment. This paper experimentally demonstrates how a macro fiber composite actuator can statically and dynamically excite a stowed composite tape spring to initiate unrolling into its extended state. A finite element model in Abaqus/Explicit is also developed to computationally corroborate the deployment schemes discussed.

  PublisherDOI

• Characterization of Nonlinear Vibrations in Composite Tape Spring Hinges

  2025-01-03 · 1 citations

  articleSenior author

  The nonlinear steady-state responses for a thin-shelled composite tape spring hinge under translational base harmonic excitation are characterized both experimentally and through finite element analysis. The motivation is to investigate how the nonlinear elastic deformation modes associated with pre-buckled and post-buckled stability regimes manifest into dynamic responses when a tape spring shell is subject to large amplitude vibrations. The first two linear vibration modes are found to be a twisting mode and a bending mode in both high-speed digital image correlation tests and finite element analysis. Forward and backward frequency sweeps across the dominant bending mode are then experimentally conducted with a shaker setup and through nonlinear dynamic implicit simulations in Abaqus. The hinge structure is found to exhibit broadband nonlinear steady-state responses consisting of flexural-torsional, subharmonic, superharmonic, and chaotic oscillations as well as intermittencies. There is correlation between the experimental and simulation results in terms of the steady-state amplitudes and frequency content, nonlinear bandwidths, and response type. A detailed characterization is made for each observed response by visualizing both global and local deformations for the tape spring hinge.

  PublisherDOI

• Deployment of bistable composite tape springs with non-uniform curvatures

  Composite Structures · 2025-05-12 · 5 citations

  articleOpen accessSenior authorCorresponding

  The uncoiling deployment of bistable composite tape springs with parabolic, elliptical, catenary, and circular cross-sections are investigated. Unlike cylindrical monostable shells, bistable tape springs exhibit a smooth unrolling motion when actuated beyond their strain energy peak dividing the stable coiled and extended equilibrium states. The main contribution by this paper is characterizing the advantages in the deployment behavior of bistable tape springs if their cross-section deviates from the ubiquitous circular profile. The uncoiling deployment of cantilevered tape springs with optimized profiles is initiated with a linear actuator, measured with a motion capture system, and correlated with finite element analysis. The elliptical tape spring is found to uncoil the furthest from the root before exhibiting instability driven self-deployment, but has the shortest self-deployment duration due to releasing the largest amount of strain energy. Having the most energetic deployment is advantageous if boom lengths are to be scaled larger because more mass needs to be translated. The elliptical cross-section is also found to have the best stiffness performance while being most stowed volume efficient. Conversely, the circular tape spring has the slowest self-deployment due to releasing the least amount of strain energy.

  PublisherDOI

• Nonlinear Vibrations from Local Shell Buckling in Composite Tape Spring Hinges

  International Journal of Solids and Structures · 2025-01-01

  preprintOpen accessSenior author
  PublisherOA PDFDOI

• Uncoiling Deployment of Bistable Composite Booms With Elliptical, Parabolic, and Catenary Profiles

  2025-01-03

  articleSenior author

  The uncoiling dynamic deployment of bistable thin-shelled composite tape spring booms with parabolic, elliptical, catenary, and circular cross-sections are investigated and compared. Unlike cylindrical monostable shells, bistable composite tape springs exhibit a smooth unrolling motion when actuated beyond their strain energy peak dividing the stable coiled and extended equilibrium states. The motivation is to identify any advantages or efficiencies in the uncoiling behavior and deployment path of bistable tape springs if their cross-sectional shape deviates from the ubiquitous circular profile. A parametric analysis based on an inextensional analytical model first optimizes the different cross-sectional profiles based on their critical stiffness property and stable coiled diameter. The elliptical cross-section is found to have the best stiffness performance while being most efficient in terms of stowed volume. The uncoiling deployment of 1 m cantilevered tape springs with the optimized profiles are initiated with a linear actuator, measured with a motion capture system, and correlated with finite element analysis. The elliptical tape spring is found to uncoil the furthest out from the fixed root before exhibiting instability driven self-deployment, but has the shortest self-deployment duration due to releasing the largest amount of strain energy. Conversely, the parabolic tape spring uncoils the least before self-deploying but also exhibits the second slowest extension. The circular tape spring has the slowest self-deployment due to releasing the least amount of strain energy.

  PublisherDOI

Frequent coauthors

• Daniel J. Inman

  Michigan United

  21 shared

• Amin Moosavian

  Toronto Metropolitan University

  10 shared

• Jacob G. Daye

  North Carolina State University

  9 shared

• Juan M. Fernandez

  8 shared

• Saad Shabeer

  North Carolina State University

  4 shared

• Eun Jung Chae

  California State University, Long Beach

  4 shared

• Michael Danielczuk

  Berkeley Systems (United States)

  3 shared

• Art MacCarley

  3 shared

Labs

• Andrew Lee LabPI