Abstract Hydrogel can swell to many times of its dry volume, resulting in large deformation which is vital for its function. The swelling process is regulated by many physical and chemical mechanisms, and can, to some...Abstract Hydrogel can swell to many times of its dry volume, resulting in large deformation which is vital for its function. The swelling process is regulated by many physical and chemical mechanisms, and can, to some extent, be fairly described by the poroelasticity theory. Implementation of the poroelastieity theory in the framework of finite element method would aid the design and optimization of hydrogel-based soft devices. Choosing chemical potential and displacement as two field variables, we present the implementation of poroelastieity tailored for hydrogel swelling dynamics, detail the normalization of physical parameters and the treatment of boundary conditions. Several examples are presented to demonstrate the feasibility and correctness of the proposed strategy.展开更多
Cylinder hydrogel is simple in geometry and easy to synthesize, therefore was widely used to investigate the swelling/shrinking instability of hydrogel and many instability patterns were accumulated in the literature....Cylinder hydrogel is simple in geometry and easy to synthesize, therefore was widely used to investigate the swelling/shrinking instability of hydrogel and many instability patterns were accumulated in the literature. The mechanism of instability pattern formation of this unique configuration, nevertheless, is far from being fully understood. We applied and extended the re- cently developed nonlinear theory of polymer gels into cylindrical coordinates, and performed linear perturbation analysis of swelling-induced stability of a constrained cylinder hydrogel. We derived the incremental formulations of stresses and the associated equilibrium equations. We obtained the critical conditions for the onset of instability and probed in details the effects of var- ious parameters on the stability diagram of the hydrogel. The physical meaning of the variation of stability diagram was also interpreted.展开更多
We report the first attempt to model the contacts of an ionic polymer metal composite（IPMC） based tactile sensor. The tactile sensor comprises an IPMC actuator, an IPMC sensor and the target to be detected. The syst...We report the first attempt to model the contacts of an ionic polymer metal composite（IPMC） based tactile sensor. The tactile sensor comprises an IPMC actuator, an IPMC sensor and the target to be detected. The system makes use of multiple contacts to work： the actuator comes into contact with the sensor and pushes the movement of sensor; the contact between the sensor and the object detects the existence and the stiffness of the target. We integrate modeling of various physical processes involved in IPMC devices to form a simulation scheme. An iteration and optimization strategy is also described to correlate the experimental and simulation results of an IPMC bending actuator to identify the two key parameters used in electromechanical transduction. Modeling the multiple contacts will aid the design and optimization of such IPMC based soft robotics.展开更多
基金supported by the National Natural Science Foundation of China(11072185,11372239,and 11021202)
文摘Abstract Hydrogel can swell to many times of its dry volume, resulting in large deformation which is vital for its function. The swelling process is regulated by many physical and chemical mechanisms, and can, to some extent, be fairly described by the poroelasticity theory. Implementation of the poroelastieity theory in the framework of finite element method would aid the design and optimization of hydrogel-based soft devices. Choosing chemical potential and displacement as two field variables, we present the implementation of poroelastieity tailored for hydrogel swelling dynamics, detail the normalization of physical parameters and the treatment of boundary conditions. Several examples are presented to demonstrate the feasibility and correctness of the proposed strategy.
基金supported by the National Natural Science Foundation of China (Nos. 11072185,10872157 and 11021202)
文摘Cylinder hydrogel is simple in geometry and easy to synthesize, therefore was widely used to investigate the swelling/shrinking instability of hydrogel and many instability patterns were accumulated in the literature. The mechanism of instability pattern formation of this unique configuration, nevertheless, is far from being fully understood. We applied and extended the re- cently developed nonlinear theory of polymer gels into cylindrical coordinates, and performed linear perturbation analysis of swelling-induced stability of a constrained cylinder hydrogel. We derived the incremental formulations of stresses and the associated equilibrium equations. We obtained the critical conditions for the onset of instability and probed in details the effects of var- ious parameters on the stability diagram of the hydrogel. The physical meaning of the variation of stability diagram was also interpreted.
基金supported by the National Natural Science Foundation of China(Nos.11372239,11321062 and 11472210)
文摘We report the first attempt to model the contacts of an ionic polymer metal composite（IPMC） based tactile sensor. The tactile sensor comprises an IPMC actuator, an IPMC sensor and the target to be detected. The system makes use of multiple contacts to work： the actuator comes into contact with the sensor and pushes the movement of sensor; the contact between the sensor and the object detects the existence and the stiffness of the target. We integrate modeling of various physical processes involved in IPMC devices to form a simulation scheme. An iteration and optimization strategy is also described to correlate the experimental and simulation results of an IPMC bending actuator to identify the two key parameters used in electromechanical transduction. Modeling the multiple contacts will aid the design and optimization of such IPMC based soft robotics.
