Realistic simulation of active origami structures with multi-physics behaviors. The package can capture compliant creases, inter-panel contact, heat transfer, large folding deformation, and electro-thermally actuated creases. The package provides six different loading methods adn allows users to created customizable loading schemes with arbitrary number and sequence of the provided loading methods.
Please check the package on our group website or my personal website:
https://drsl.engin.umich.edu/software/swomps-package/
https://sites.google.com/view/yi-zhu/research/origami-simulator/
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Provides six different loading simulation methods:
- (1) Newton-Raphson method, (2) Displacement controlled method, and (3) Generalized displacement controlled method for applying external forces.
- (4) Changing stress-free folding angle for self-folding.
- (5) Changing environmetnal temperature and (6) applying electro-thermal actuation for thermally active self-folding.
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Allows users to create customizable loading schemes with arbitrary number and sequence of the provided five loading methods.
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Simulates compliant creases in active origami and provides automated Meshing code for compliant creases. (Figure 1)
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Simulates inter-panel contact induced mechanical behaviors within origami. (Figure 2)
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Simulates heat transfer in origami systems and captures the electro- thermo-mechanically coupled actuation of active origami creases. (Figure 3)
Figure 1. The package allows users to simulate origami systems with compliant creases, which are creases with non-negligible width. Using the compliant crease meshing provides more realistic geometry and allows the simulator to capture advanced mechanical behaviors such as bistability and multi-physics actuation.
Figure 2. The package allows users to simulate global inter-panel contact within the origami. This panel contact model is a physics-based frictionless contact model and can give the correponding forcese between the contacting panels.
Figure 3. The package allows users to simulate multi-physics based electro-thermal actuation in the origami creases. The package can capture the heat transfer of active origami and can calculate the active crease folding due to changing temperature.
This code is based on bar and hinge models for origami structures. The bar and hinge model is a reduced order simulation method for capturing the kinematic and mechanical behaviors of origami structures. There are different ways for deriving the stiffness parameters of a bar and hinge model, and these methods produce different results. In this simulation package, the stiffness parameters are derived analytically through matching the stiffness from the bar and hinge model to that from the the theoretical plate (for shear and tension) and the pseudo-rigid-body model (for large folding). This derivation method does not capture large panel deformations with high fidelity, especially when studying non-rigid foldable origami patterns. Most paper-based non-rigid foldable origami prototypes can have panels with initial curvature and bending. Therefore, the bar and hinge model can over-estimate the stiffness of these prototypes because it cannot capture the softening due to the initial curving and bending (which requires capturing the softened post-buckling stiffness). To resolve this, many researchers will use curve-fitting to find out the stiffness parameters of bars and rotational springs (say fitting the Young's modulus). In this case, curve-fitting is like using the secant stiffness (while analytically derivation is like using the initial tangent stiffness), so the curve-fitting method can better approximate the softened stiffness of many non-rigid foldable origami prototypes. Users of the code are suggested to try curve-fit the stiffness parameters (such as Young's modulus) if high accuracy is needed for simulating non-rigid foldable systems and matching the behaviors in origami prototypes. However, the results from analytical derivation still provides a fast alternative for finding the trends and understanding the behaviors of origami systems.
Part of the code is vectorized now. I cannot believe that I did not do it previously. This probably shows the beauty of bar and hinge models; you can follow bad coding habbit and still get reasonalbly fast results. Thankfully, one of my wafer is stuck in the machine and the lab staff is crazily busy recently so he cannot remove it for me. This prevents me from doing micro-fab so I have an entire weekend plus a couple week days to sit down and vectorize my previous codes. In addition to vectorizing the code for mechanical simulation, part of the code for thermal simulaiton is streamlined to reduce redundant calculation.
Figure 4. For the "Example06_FlowerSelfFold.m" the new version is roughly five times faster than the previous code. For the simulation of the SWOMPS logo, the new code is about three times faster than the previous code.
PLEASE ADD THE "00_SourceCode" IN TO THE PATH. For standard mechanical simulation of origami, please check the selected simulaiton example from the JMR paper and PRSA paper in "01_MechanicalLoadingExample". For simulation of the folding electro-thermally active origami, please check the example codes in "02_ThermalLoadingExample" associated with the IJMS paper. Additional tutuorial examples are presented in the "03_SampleCode_Tutorial_IDETC".
We would like to acknowledge the prior works from Ke Liu and Glaucio H. Paulino for non-rigid origami simulators. Their works pave the ground for the development of this package.
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Y. Zhu, E. T. Filipov (2021) Sequentially Working Origami Multi-Physics Simulator (SWOMPS): A Versatile Implementation, IDETC-CIE 2021, DETC2021-68042.
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Y. Zhu, E. T. Filipov (2021) Rapid Multi-Physics Simulation for Electro-Thermal Origami Systems. International Journal of Mechanical Sciences, 202-203, 106537.
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Y. Zhu, E. T. Filipov (2020). A Bar and Hinge Model for Simulating Bistability in Origami Structures With Compliant Creases, Journal of Mechanisms and Robotics, 12, 021110-1.
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Y. Zhu, E. T. Filipov (2019). An Efficient Numerical Approach for Simulating Contact in Origami Assemblage, Proceedings of the Royal Society A, 475, 20190366.
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Y. Zhu, E. T. Filipov (2019). Simulating compliant crease origami with a bar and hinge model. IDETC/CIE 2019, 97119.
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K. Liu, G. H. Paulino (2018). Highly efficient nonlinear structural analysis of origami assemblages using the MERLIN2 software, Origami^7.
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K. Liu, G. H. Paulino (2017). Nonlinear mechanics of non-rigid origami – An efficient computational approach, Proceedings of the Royal Society A, 473, 20170348.
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K. Liu, G. H. Paulino (2016). MERLIN: A MATLAB implementation to capture highly nonlinear behavior of non-rigid origami, Proceedings of IASS Annual Symposium 2016.