https://doi.org/10.5061/dryad.2bvq83bx3

This repository consists of both data files and MATLAB software files. The experimental setup for this data and software is a linear shape memory alloy (SMA, Flexinol HT) wire actuated under a constant bias mass and the same SMA wire coupled to a steel beam resulting in a bending structure. The experimental data is the electrical input power and visual marker data captured by a high speed camera for various tests run (to be explained in the following sections). The software files then simulate the SMA response using the electrical power data as an input into the model. The resulting model results are then compared to the experimental visual marker data to assess the accuracy of the model. For the linear SMA model, the root mean squared error for the various input waveforms was an average of 0.003 strain. For the unimorph SMA, the root mean squared error of the configuration was an average of 1.38 mm.

Description of the data and file structure

The data set includes data for both a linear and morphing SMA actuator.

Linear SMA Data
The linear SMA data set includes:

1. lengthWireMat_step1.mat
2. lengthWireMat_sine1.mat
3. lengthWireMat_trap2.mat
4. powerMat_step1.mat
5. powerMat_sine1.mat
6. powerMat_trap2.mat

The files beginning with "lengthWireMat_" contain the length of the SMA wires captured by the high speed camera (at 100 Hz). The files beginning with "powerMat_" contain the time vector for the electrical power in the first column, the voltage reading from the power supply in the second column, and the current reading from the power supply in the third column. This data is recorded by the power supply itself. Three electrical waveforms were tested: a sinusoidal input (sine1), a step input (step1), and a trapezoidal input (trap2).

Unimorph SMA Data
The unimorph SMA data set includes:

1. expX_metalCCS_small_test2.mat
2. expY_metalCCS_small_test2.mat
3. expX_metalCCS_big_test2.mat
4. expY_metalCCS_big_test2.mat
5. powerMat_metalCCS_small_test2.mat
6. powerMat_metalCCS_big_test2.mat

The files beginning with "expX_" contain the X coordinates of the SMA unimorph actuator captured by the high speed camera (at 100 Hz). The files beginning with "expY_" contain the Y coordinates of the SMA unimorph actuator captured by the high speed camera (at 100 Hz). There are a total of 11 markers on each actuator located at 10 mm intervals along the length. The files beginning with "powerMat_" contain the time vector for the electrical power in the first column, the voltage reading from the power supply in the second column, and the current reading from the power supply in the third column. This data is recorded by the power supply itself. There are two different actuators tested in this work (labeled "big_test2" and "small_test2"). This refers to the offset distance between the SMA wire and the beam (big = 1.00 mm and small = 0.675 mm). The rest of the attributes of the actuators are the same.

Code/Software

The code was run on MATLAB 2022b.
The Hybrid Equations Toolbox was used to implement the hybrid dynamical equations (Ricardo Sanfelice (2023). Hybrid Equations Toolbox (https://github.com/pnanez/HyEQ_Toolbox/releases/tag/3.0.0.76), GitHub. Retrieved November 5, 2023.)

Linear SMA Software
The software files used specifically for the linear data include:

1. mainSMALinear.m
2. smaMaterialModelLinear.m
3. delFunLin.m

The main .m file is used to run the MATLAB model and the calls the other functions. The "smaMaterialModelLinear" contains the hybrid model for the linear SMA model to model the continuous and discrete states. The "delFunLin.m" is a function that calculates the derivatives of the states.

Unimorph SMA Software
The software files used specifically for the linear data include:

1. mainSMABending.m
2. smaMaterialModel.m
3. delFun.m
4. twoDBeamSMA.m

The main .m file is used to run the MATLAB model and the calls the other functions. The "smaMaterialModel" contains the hybrid model for the unimorph SMA model to model the continuous and discrete states. The "delFun.m" is a function that calculates the derivatives of the states.

Mutual Functions
The following functions are used by both the linear and unimorph model:

1. smaVariableStructure.mat (imports various material properties and simulation parameters)
2. seriesFun.m (function for series addition of material properties)
3. strainFun.m (function for strain calculation)

Implementation
In order to run the model, run the "main" files. These files are set up to pull the experimental data from a folder (change if pulled from the same directory)