Open Access. Powered by Scholars. Published by Universities.®
- Keyword
-
- Frequency tuning (2)
- Viscoelasticity (2)
- Collocated grid (1)
- Crack tip opening displacement (CTOD) (1)
- Die-Casting modeling (1)
-
- Dielectric elastomer (1)
- Dielectric elastomer transducers (1)
- Electrical breakdown. (1)
- Electromechanical coupling (1)
- Energy harvesting (1)
- Finite Volume Method (1)
- Finite element analyses (1)
- Fracture toughness (1)
- J-integral (1)
- Magnesium alloys (1)
- Multiple relaxation (1)
- Nonlinear viscosity (1)
- Phase change modeling (1)
- Piezoelectric nanobeams; Piezoelectric nanoplates; Continuum modeling; Size-dependent properties; Surface effects; Flexoelectricity (1)
- Pipeline (1)
- Resonator (1)
- SE(T) specimen (1)
- Solidification modeling (1)
- Unstructured grid (1)
- Volume-Averaged technique (1)
- Wedge casting (1)
Articles 1 - 5 of 5
Full-Text Articles in Engineering Mechanics
Effect Of The Nonlinear Material Viscosity On The Performance Of Dielectric Elastomer Transducers, Yuanping Li
Effect Of The Nonlinear Material Viscosity On The Performance Of Dielectric Elastomer Transducers, Yuanping Li
Electronic Thesis and Dissertation Repository
As a typical type of soft electroactive materials, dielectric elastomers (DEs) are capable of producing large voltage-induced deformation, which makes them desirable materials for a variety of applications in transduction technology, including tunable oscillators, resonators, biomimetics and energy harvesters. The dynamic and energy harvesting performance of such DE-based devices is strongly affected not only by multiple failure modes such as electrical breakdown, electromechanical instability, loss-of-tension and fatigue, but also by their material viscoelasticity. Moreover, as suggested by experiments and theoretical studies, DEs possess nonlinear relaxation processes, which makes modeling of the performance of DE-based devices more challenging.
In this thesis, …
Effect Of Material Viscoelasticity On Frequency Tuning Of Dielectric Elastomer Membrane Resonators, Liyang Tian
Effect Of Material Viscoelasticity On Frequency Tuning Of Dielectric Elastomer Membrane Resonators, Liyang Tian
Electronic Thesis and Dissertation Repository
Dielectric elastomers (DEs) capable of large voltage-induced deformation show promise for applications such as resonators and oscillators. However, the dynamic performance of such vibrational devices is not only strongly affected by the nonlinear electromechanical coupling and material hyperelasticity, but also significantly by the material viscoelasticity. The material viscoelasticity of DEs originates from the highly mobile polymer chains that constitute the polymer networks of the DE. Moreover, due to the multiple viscous polymer subnetworks, DEs possess multiple relaxation processes. Therefore, in order to predict the dynamic performance of DE-based devices, a theoretical model that accounts for the multiple relaxation processes is …
Numerical Studies For Improving Fracture Toughness Resistance Curve Testing Using Single-Edge (Notched) Tension Specimens, Yifan Huang
Electronic Thesis and Dissertation Repository
The fracture toughness resistance curve, i.e. the J-integral resistance curve (J-R curve) or the crack tip opening displacement resistance (CTOD-R) curves, is widely used in the integrity assessment and strain-based design of energy pipelines with respect to planar defects (i.e. cracks). This thesis deals with issues related to the experimental determination of the J(CTOD)-R curves using the newly-developed single-edge (notched) tension (SE(T)) specimens. In the first study, the plastic geometry factor, i.e. the ηpl factor, used to evaluate J in a J-R curve test based on …
Numerical Modeling Of Solidification Process And Prediction Of Mechanical Properties In Magnesium Alloys, Mehdi Farrokhnejad
Numerical Modeling Of Solidification Process And Prediction Of Mechanical Properties In Magnesium Alloys, Mehdi Farrokhnejad
Electronic Thesis and Dissertation Repository
A formulation used to simulate the solidification process of magnesium alloys is developed based upon the volume averaged finite volume method on unstructured collocated grids. To derive equations, a non-zero volume fraction gradient has been considered and resulting additional terms are well reasoned. For discretization the most modern approximations for gradient and hessians are used and novelties outlined. Structure-properties correlations are incorporated into the in-house code and the proposed formulation is tested for a wedge-shaped magnesium alloy casting. While the results of this study show a good agreement with the experimental data, it was concluded that a better understanding of …
Continuum Modeling On Size-Dependent Properties Of Piezoelectric Nanostructures, Zhi Yan
Continuum Modeling On Size-Dependent Properties Of Piezoelectric Nanostructures, Zhi Yan
Electronic Thesis and Dissertation Repository
Piezoelectric beam- and plate-based nanostructures hold a promise for device applications in the nanoelectromechanical systems (NEMS) due to their superior mechanical and electromechanical coupling properties. “Small is different”, nanostructured piezoelectric materials exhibit size-dependent properties, which are different from their bulk counterparts. For predicting the unique physical and mechanical properties of these novel nanostructures, continuum mechanics modeling has been regarded as an efficient tool. However, the conventional continuum models fail to capture the size effects of nanostructures and thus are not directly applicable at the nanoscale. Therefore, it is necessary to develop modified continuum models for piezoelectric nanostructures by incorporating the …