Model predictions of hydro-mechanical coupling in unsaturated crushable soils

2014 ◽  
pp. 471-477
Author(s):  
Y Zhang ◽  
G Buscarnera
Keyword(s):  
Mechanical Coupling ◽  
Model Predictions

Photomechanics of Light-Activated Shape Memory Polymers

2008 ◽  
Author(s):  
Kevin N. Long ◽  
Timothy F. Scott ◽  
H. Jerry Qi ◽  
Martin L. Dunn
Keyword(s):  
Shape Memory ◽  
Mechanical Response ◽  
Irradiation Time ◽  
Shape Memory Polymer ◽  
Polymer System ◽  
Shape Memory Polymers ◽  
Model Parameters ◽  
Model Framework ◽  
Mechanical Coupling ◽  
Model Predictions

Photomechanical shape memory polymers are an exciting class of materials that are able to store a temporary shape and recover their original shape when stimulated by light. In this work we develop a model to simulate the photomechanical behavior of light-activated shape memory polymers. To the best of our knowledge this is the first theoretical model developed to describe this exciting class of active materials. Our model incorporates the interplay among four aspects of the underlying physical phenomena: light propagation, photo-chemistry, chemical-mechanical coupling, and mechanical response. The model framework is applied to a recently developed photo-induced shape memory polymer system [1, 2]. We describe a suite of experiments used to guide the modeling efforts, calibrate the model parameters, and then validate model predictions. Regarding the latter, we measure and then simulate the photo-induced bending behavior of shape memory polymer samples; model predictions are in good agreement with measurements. We use the model to then explore the effect of important photomechanical parameters (applied strain magnitude, irradiation time and intensity, and photoabsorber concentration) on material response with a view toward the design of novel actuator materials and structures.

scholarly journals Magneto-Mechanical Coupling in Magneto-Active Elastomers

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 434
Author(s):  
Philipp Metsch ◽  
Dirk Romeis ◽  
Karl A. Kalina ◽  
Alexander Raßloff ◽  
Marina Saphiannikova ◽  
...  
Keyword(s):  
Particle Interaction ◽  
Helical Structures ◽  
Systematic Comparison ◽  
Mechanical Coupling ◽  
Basic Assumptions ◽  
Modeling Approaches ◽  
Model Predictions ◽  
Interaction Approach ◽  
Remarkable Agreement

In the present work, the magneto-mechanical coupling in magneto-active elastomers is investigated from two different modeling perspectives: a micro-continuum and a particle–interaction approach. Since both strategies differ significantly in their basic assumptions and the resolution of the problem under investigation, they are introduced in a concise manner and their capabilities are illustrated by means of representative examples. To motivate the application of these strategies within a hybrid multiscale framework for magneto-active elastomers, their interchangeability is then examined in a systematic comparison of the model predictions with regard to the magneto-deformation of chain-like helical structures in an elastomer surrounding. The presented results show a remarkable agreement of both modeling approaches and help to provide an improved understanding of the interactions in magneto-active elastomers with chain-like microstructures.

A two degrees of freedom comb capacitive-type accelerometer with low cross-axis sensitivity

2019 ◽  
Vol 13 (3) ◽  
pp. 5334-5346
Author(s):  
M. N. Nguyen ◽  
L. Q. Nguyen ◽  
H. M. Chu ◽  
H. N. Vu
Keyword(s):  
Degrees Of Freedom ◽  
Proof Mass ◽  
Vibration Modes ◽  
Electrode Structure ◽  
Element Analysis ◽  
Mechanical Coupling ◽  
Fully Differential ◽  
Mode Effects ◽  
The Finite Element Analysis ◽  
Cross Axis

In this paper, we report on a SOI-based comb capacitive-type accelerometer that senses acceleration in two lateral directions. The structure of the accelerometer was designed using a proof mass connected by four folded-beam springs, which are compliant to inertial displacement causing by attached acceleration in the two lateral directions. At the same time, the folded-beam springs enabled to suppress cross-talk causing by mechanical coupling from parasitic vibration modes. The differential capacitor sense structure was employed to eliminate common mode effects. The design of gap between comb fingers was also analyzed to find an optimally sensing comb electrode structure. The design of the accelerometer was carried out using the finite element analysis. The fabrication of the device was based on SOI-micromachining. The characteristics of the accelerometer have been investigated by a fully differential capacitive bridge interface using a sub-fF switched-capacitor integrator circuit. The sensitivities of the accelerometer in the two lateral directions were determined to be 6 and 5.5 fF/g, respectively. The cross-axis sensitivities of the accelerometer were less than 5%, which shows that the accelerometer can be used for measuring precisely acceleration in the two lateral directions. The accelerometer operates linearly in the range of investigated acceleration from 0 to 4g. The proposed accelerometer is expected for low-g applications.

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