A5018618524- Advancements in Solid Oxide Fuel Cells
- Structural Analysis and Optimization
- Advanced ceramic materials synthesis
- Advanced Materials and Mechanics
- Fuel Cells and Related Materials
- Mechanical Behavior of Composites
- Elasticity and Material Modeling
- Composite Material Mechanics
- Carbon Nanotubes in Composites
- Nuclear Materials and Properties
- Electronic and Structural Properties of Oxides
- Conducting polymers and applications
- Composite Structure Analysis and Optimization
- Textile materials and evaluations
- Polymer composites and self-healing
- Advanced materials and composites
- Dynamics and Control of Mechanical Systems
- Astro and Planetary Science
- Vibration and Dynamic Analysis
- Mechanical stress and fatigue analysis
- Innovations in Concrete and Construction Materials
- Advanced Sensor and Energy Harvesting Materials
- Planetary Science and Exploration
- Silicone and Siloxane Chemistry
- Polymer Nanocomposites and Properties
Purdue University West Lafayette
2024-2025
University of Central Florida
2017-2024
Technical University of Denmark
2013-2020
California Institute of Technology
2009-2015
The viscoelastic behavior of polymer composites decreases the deployment force and postdeployment shape accuracy composite deployable space structures. This paper presents a model for single-ply cylindrical shells (tape springs) that are deployed after being held folded given period time. is derived from representative unit cell material, based on microstructure geometry. Key ingredients fiber volume density in tows constitutive fibers (assumed to be linear elastic transversely isotropic)...
This paper presents an experimental and numerical study of the folding, stowage, deployment behavior viscoelastic tape springs. Experiments show that during folding relationship between load displacement is nonlinear varies with rate temperature. In particular, limit propagation loads increase but decrease During relaxation leads to a reduction in internal forces significantly impacts subsequent dynamics. The starts short, dynamic transient followed by steady ends slow creep recovery. Unlike...
Abstract Thermal cycling and creep in metallic interconnects during operation of solid oxide cell (SOC) stacks could cause contact losses the interface between interconnect cells. The magnitude stress its distribution within SOC stack depends on overall design operating conditions. In this study, stresses different types generic designs caused by external loading temperature variations through long‐term are investigated. investigation includes with without components combined machined...
An electro-active composite based on carbon nanopaper (CNP) shape memory polymer (SMP) is proposed for actuating deployment of deployable structures. Carbon composites are stimuli-responsive materials that can change between programmed shapes and the original by a voltage input. The sandwich structure where CNP layer acts as flexible electrical heater when difference applied. behavior CNP-SMP presents coupled electrical-thermal-structural problem. This paper combined experimental, numerical,...
Carbon nanotube polymer composites exhibit piezoresistivity that can be utilized for flexible strain sensors. Piezoresistive modeling is critical improving sensor performance, but remains a challenging subject due to the complex CNT network microstructure and various effects occurring at both micro nano scales. Tunneling conduction between CNTs primary mechanism underlying in carbon composites. Existing models have employed myriad of assumptions on kinematics tunneling behavior, their...
Following recent interest in constructing large self-deployable structures made of reinforced polymer materials, this paper presents a detailed study viscoelastic effects folding, stowage, and deployment tape-springs which often act as actuators space structures.Folding stowage behavior at different temperatures rates are studied.It is found that the peak load increases with folding rate but reduces temperature.It also shown reduction much 60% possible during due to relaxation...
Abstract The deployment of viscoelastic structures that have been held stowed for a given time duration can be formulated as boundary value problem in which the prescribed condition switches from constant displacement to traction. This paper presents closed-form expressions load relaxation and shape recovery linear beam subject such time-varying constraints. It is shown recovers its original asymptotically over time. analytical solutions are employed investigate effect temperature stowage on...
The first part of the paper presents an experimental study deployment and shape recovery composite tape-springs after stowage at elevated temperature.It is found that deploy quickly with a slight overshoot, but complete takes place asymptotically over time.Stowage has effect slowing down both shortterm long-term recovery.The second micromechanical finite element homogenization scheme to determine effective viscoelastic properties woven laminas.This solution employed in numerical simulations...
Composites are excellent material candidates for large deployable spacecraft structures. Prior to deployment in space, these structures stowed the furled configuration prolonged periods. The mechanical response of composite laminates used is greatly influenced by viscoelasticity polymer matrix. Characterization viscoelastic properties time-consuming because necessity test at multiple temperatures and stress levels. present study reports an experimental method testing composites with high...
Buckling instabilities can be actively utilized to design deployable structures for unique aerospace applications. New concepts propeller blades based on thin-shell buckling have recently been proposed launching aerial vehicles in constrained environments such as from portable launchers and undersea submarines. Deployable collapsed folded or rolled up during storage launching, self-deploy operation. To utilize propellers, sufficient pre-buckling stiffness resist aerodynamic loads but...
The paper investigates the shape recovery behavior of a simple beam and tape spring made LDPE under prescribed deformation history at room temperature.The linear viscoelastic material properties were measured via creep tests.An analysis four-point bending with an imposed vertical deflection reaction force was performed.A theoretical solution constructed by employing Alfrey's Correspondence Principle to Euler-Bernoulli equation.The result validated against experiment detailed nonlinear finite...