A Computing Method to Determine the Performance of an Ionic Liquid Gel Soft Actuator.

Bin He,Zhipeng Wang,Chenghong Zhang,Yanmin Zhou

doi:10.1155/2018/8327867

Abstract

A new type of soft actuator material—an ionic liquid gel (ILG) that consists of BMIMBF4, HEMA, DEAP, and ZrO2—is polymerized into a gel state under ultraviolet (UV) light irradiation. In this paper, we first propose that the ILG conforms to the assumptions of hyperelastic theory and that the Mooney-Rivlin model can be used to study the properties of the ILG. Under the five-parameter and nine-parameter Mooney-Rivlin models, the formulas for the calculation of the uniaxial tensile stress, plane uniform tensile stress, and 3D directional stress are deduced. The five-parameter and nine-parameter Mooney-Rivlin models of the ILG with a ZrO2 content of 3 wt% were obtained by uniaxial tensile testing, and the parameters are denoted as c10, c01, c20, c11, and c02 and c10, c01, c20, c11, c02, c30, c21, c12, and c03, respectively. Through the analysis and comparison of the uniaxial tensile stress between the calculated and experimental data, the error between the stress data calculated from the five-parameter Mooney-Rivlin model and the experimental data is less than 0.51%, and the error between the stress data calculated from the nine-parameter Mooney-Rivlin model and the experimental data is no more than 8.87%. Hence, our work presents a feasible and credible formula for the calculation of the stress of the ILG. This work opens a new path to assess the performance of a soft actuator composed of an ILG and will contribute to the optimized design of soft robots.

Highlights

At room temperature, the ionogel is a polymerized gelatinous mixture from the ionic liquid and polymer matrix under UV irradiation [1, 2]
Wang et al established a model based on the finite element method (FEM) to determine the electromechanical bending behavior of photocurable ionogel actuators (PIA) [16]
The tensile stress-strain curve of the Ionic liquid gels (ILG) is shown in Figure 7, and the average tensile strength (Young’s modulus) of the material obtained from the tensile stress-strain curve is 7.6 kPa

Summary

Introduction

The ionogel is a polymerized gelatinous mixture from the ionic liquid and polymer matrix under UV irradiation [1, 2]. Noncovalent interactions provide the gels with the very high mechanical strength and excellent self-healing ability of supramolecular materials [11, 12] Based on these studies, we used ZrO2 to fabricate supramolecular nanocomposites with the electrochemical behavior of an ionic liquid and mechanical strength of an ionogel polymer. Finite element analysis is one of the most effective and most common information extraction methods to evaluate and optimize robot designs By using this method, analytical models can be greatly simplified, which greatly increases the computational efficiency. Wang et al established a model based on the FEM to determine the electromechanical bending behavior of photocurable ionogel actuators (PIA) [16] He et al used the common large-scale finite element analysis software ANSYS to simulate an ILG, which is based on the SOLID186 element and the nonlinear hyperelastic Mooney-Rivlin model [17]. The numerical simulation results matched the corresponding experiments, proving the validity of the model [18, 19]

Fabrication of the Ionic Liquid Gel

Material Nonlinearity and Parameters

Stress Calculation

Experimental Analysis

Conclusions