Computational Modeling of Pneumatically Actuated Metamaterials with Third Medium Contact Formulation

Conceptos Básicos

A novel hyperelastic third medium material model is proposed to enable concurrent modeling of pneumatic actuation and contact in computational analysis of metamaterials and soft robotic structures.

Resumen

The content presents a new computational approach for modeling pneumatically actuated metamaterials that exhibit internal contact. The key highlights are:

1. Pneumatic actuation is represented exactly as a prescribed Cauchy stress in the material voids, improving on previous approximate methods.
2. A third medium contact formulation is used, which avoids the need to explicitly define contact interfaces.
3. The third medium model comprises three distinct energy terms: one for pneumatic actuation, one for contact enforcement, and one for regularization to stabilize the compliant third medium.
4. The regularization term is based on penalizing material gradients of rotation and volume change, which improves the compliant behavior of the third medium compared to previous approaches.
5. The proposed formulation is energetically consistent, enabling the use of advanced finite element solvers.
6. The method is demonstrated on several numerical examples, including a patch test, a self-contact benchmark, and the simulation of a pneumatically actuated pattern-forming metamaterial, validating it against experimental data.

Estadísticas

The critical pressure difference leading to internal buckling of the pneumatically actuated metamaterial sample was experimentally measured as (∆p)crit = -8.45 kPa ± 0.3 kPa.
The corresponding critical pressure difference obtained in the numerical simulation was (∆p)crit = -8.96 kPa.

Citas

"A novel hyperelastic third medium material model is proposed to enable concurrent modeling of pneumatic actuation and contact in computational analysis of metamaterials and soft robotic structures."
"The regularization term is based on penalizing material gradients of rotation and volume change, which improves the compliant behavior of the third medium compared to previous approaches."
"The proposed formulation is energetically consistent, enabling the use of advanced finite element solvers."

Ideas clave extraídas de

Third Medium Finite Element Contact Formulation for Pneumatically Actuated Systems

by Ondř... a las arxiv.org 05-03-2024

https://arxiv.org/pdf/2405.01185.pdf

Consultas más profundas

How could this third medium contact formulation be extended to 3D applications?

The extension of the third medium contact formulation to 3D applications would involve adapting the existing 2D formulation to account for the additional complexities of three-dimensional space. One key aspect would be the inclusion of out-of-plane deformations, which are crucial in capturing the full behavior of structures in three dimensions. This would require modifications to the strain energy density function to incorporate terms that account for volumetric changes and shear deformations in all three spatial directions. Additionally, the meshing strategy would need to be adjusted to accommodate the additional dimensionality, ensuring that the third medium elements are properly aligned and interact with the solid bodies in a realistic manner. Overall, the extension to 3D applications would involve a comprehensive reevaluation and adjustment of the formulation to accurately represent the behavior of structures in three dimensions.

What are the potential limitations of the hyperelastic material model used for the third medium, and how could alternative constitutive laws be incorporated?

The hyperelastic material model used for the third medium, while effective in capturing large deformations and nonlinear behavior, has certain limitations. One limitation is that hyperelastic models are typically isotropic and homogeneous, which may not fully capture the anisotropic or heterogeneous nature of some materials. Additionally, hyperelastic models may struggle to accurately represent material behavior at high strain rates or under complex loading conditions. To address these limitations, alternative constitutive laws could be incorporated into the third medium model. For example, viscoelastic or elastoplastic models could be used to account for time-dependent or irreversible deformations. Anisotropic models could be employed to capture material behavior that varies with direction. Incorporating these alternative constitutive laws would require modifying the strain energy density function and introducing additional material parameters to characterize the specific behavior of the material being modeled.

What other types of active metamaterials or soft robotic structures could benefit from the proposed computational modeling approach?

The proposed computational modeling approach, which combines pneumatic actuation and contact in a third medium formulation, could benefit a wide range of active metamaterials and soft robotic structures. One potential application is in the design of shape-changing materials, where the ability to accurately simulate the interaction between internal voids and external forces is crucial. Soft robotic actuators, such as pneumatic artificial muscles or grippers, could also benefit from this approach by enabling more precise control and optimization of their performance. Phononic crystals, which manipulate sound waves to control the propagation of acoustic energy, could be designed and optimized using this modeling approach to achieve specific acoustic properties. Overall, any structure or material that relies on complex interactions between internal voids, external forces, and material properties could benefit from the detailed and robust computational modeling provided by this approach.