I have a question about the bending of a surface. As shown in the attached figure, I have two overlapping sheets. The top sheet has vertical red stripes, while the bottom sheet has horizontal black stripes, and these two sheets are bonded together. To clarify, these sheets are not separate; rather, there is a flexible material—such as plastic, rubber, paper, soft wood, or any other foldable material—between the colored lines, allowing the structure to bend under applied forces. Essentially, these stripes are not independent entities but integral parts of the sheet itself.
Now, when a force is applied to the top sheet (the one with red stripes) in two opposite directions, it undergoes stretching, while no direct force is applied to the bottom sheet (with black stripes). However, due to the bonding between them, the bottom sheet deforms as well, influencing the overall bending behavior of the structure. Ultimately, this results in a curved surface.
I am wondering whether it would be better to simulate this bending behavior in Grasshopper using the Kangaroo plugin or through Karamba. Any help or guidance would be greatly appreciated!
Absolutely, let’s break down how to approach this simulation in Grasshopper with Kangaroo or Karamba, considering the specifics of your layered, bonded sheet bending problem.
Understanding the Problem
Your scenario involves:
Layered Material: Two sheets (red stripes/top, black stripes/bottom) bonded together.
Material Properties: Flexible material between stripes, allowing bending.
Applied Force: Stretching on the top sheet (red stripes).
Resulting Behavior: Bending of the entire structure due to the bonded layers.
Choosing Between Kangaroo and Karamba
Both Kangaroo and Karamba can simulate bending behavior, but they approach it differently:
Kangaroo:
Primarily a physics engine for form-finding, dynamic relaxation, and interactive simulations.
Excellent for simulating flexible materials, cloth-like behavior, and interactive deformations.
Requires defining goals (e.g., length constraints, spring forces) to drive the simulation.
More suitable for complex, non-linear deformations and visually driven simulations.
Karamba:
A finite element analysis (FEA) plugin for structural analysis.
Ideal for calculating stresses, strains, and deflections in structures under load.
Requires defining material properties, boundary conditions, and loads accurately.
More suitable for precise structural analysis and engineering applications.
For your specific case, Kangaroo is likely the better choice. Here’s why:
Focus on Bending Behavior: You’re primarily interested in the bending deformation, not precise stress analysis.
Non-Linear Deformation: The layered, bonded nature of your material will likely lead to non-linear bending, which Kangaroo handles well.
Visual Feedback: Kangaroo provides interactive visual feedback, allowing you to observe the bending process in real-time.
Simplicity: setting up a basic bending simulation is easier to achieve quickly in Kangaroo.
Thank you dear Edwin for your usefull explanations. Indeed I realized kangaroo is better than karamba for this project, i think in karamba all vertices of mesh are influenced by force and total force for each point equals zero. Any way do you have any idea which component in kangaroo can define behavior of black strips? Direct force isnt applied to them and are affected by force applied to red ones, also they affect on red ones bending. So i cant define them as solids because they’re flexible themeselves.
