Open-Source Downloads

A set of zipped Abaqus CAE and INP files for modeling shell-reinforced actuators are available for free download below:

1. Bending Shell Actuators - Free Displacement Testing (One end of actuator clamped before pressurization; Other end free during pressurization)

2. Bending Shell Actuators - Blocked Force Testing (One end of actuator clamped before pressurization; Other end clamped at a specified position following initial pressurization up to a specified limit)

3. Linear Shell Actuators - Free Displacement Testing (One end of actuator clamped before pressurization; Other end free during pressurization)

4. Linear Shell Actuators - Blocked Force Testing (Both ends of actuator clamped before pressurization; Pressure increased up to a specified level afterwards)

The complete spa_guided_design_tool for modeling classical multi-chamber actuators is available to the public under the open-source MIT license. Included here is a brief description of the tools and capabilities available. The modules are all written in Python, and some modules interface with the commercial FEM software Abaqus in order to create meshes and run simulations. In order to access the complete set of scripts needed to simulate the actuators, please contact the authors with your name, affiliation and a brief description of your intended application with the aid of the SPA design tool.

spa_run_tests Used to initiate AbaqusTM and run a simulation or series of simulations. It also supports submitting jobs to high-performance compute clusters which use the SLURM queuing system.

spa_create_geom Interfaces with AbaqusTM in order to automate the process of creating a geometry, meshing it, and applying boundary conditions. Given actuator type (linear or bending), desired test (displacement or blocked force), and a set of geometric parameters such as wall thickness, chamber size, and mesh refinement, this tool will output a complete, ready-to-run AbaqusTM input file. This input file can then be run using spa_run_tests or further modified by the user using the AbaqusTM CAE interface.

spa_optimize_geometric_parameters Facilitates SPA design optimization through automated iterative design simulations, as discussed in the case studies presented here. AbaqusTM is required.

spa_calc_hyperelastic_parameters Fits experimental stress-strain data, collected through tests as described in the first Appendix, to a hyperelastic stress-strain constitutive law. AbaqusTM is not required. The following hyperelastic models are available to the user (others may be easily added):

spa_optimize_hyperelastic_parameters Performs an additional fitting step for the hyperelastic material laws in order to extrapolate missing data or optimize SPA behavior given some actuator testing data, as discussed in the section on material characterization. AbaqusTM is required.

spa_calc_viscoelastic_parameters Fits experimental stress-relaxation data, collected through tests. to a viscoelastic Prony series. AbaqusTM is not required.

spa_plot_results This module provides several useful scripts for visualizing experimental and/or simulation results, used to create the plots in this work. AbaqusTM is not required. The following scripts are included within this module: - Plot raw experimental data versus time. - Plot stress versus strain for hyperelastic testing data with fits from spa_calc_hyperelastic_parameters. - Plot optimization iteration results from spa_optimize_geometric_parameters in scatterplot form. - Plot displacement or blockedforce versus pressure from FEM simulations and/or experiments. - Plot stress versus strain for viscoelastic testing data with fits from