Ansys Structural Optimization Spider Web

The beauty hidden inside the nature empowers people to create nature-inspired solutions

Spider webs are sophisticated architectures that exhibits many mechanical function, such as catching prey, protecting offspring and support each others webs. Therefore, I am always fascinated by this nature-inspired structure and want to see their application. The paper “Structural optimization of 3D-printed synthetic webs for high strength[1]” has caught my eye, the paper found that the different loading type dictates the optimal material distribution-a homogeneous distribution is better for localized loading, while stronger radial threads with weaker spiral threads is better for distributed loading.

The diversity of Neotropical spider web architectures [2]

In this ANSYS simulated spider web optimization project, I would start by creating a synthetic spider web with the material polyethylene. Putting 12 fixed supports at the end of each threads (to simulated the spider web fixed on the tree) with the remote force exerted at the center of the web, we would observe the z direction deformation on the web. After that, we would set the radius of the thread as well as the maximum deformation as parameters to figure out how to optimize the radius of the threads and contain deformation.

Photograph of a spider web, a spider is at the center of the web [3]

Started by plotting the web structure on SolidWorks and import it into SpaceClaim, but I found out that in order to set the cross section of the threads as parameters the only method to use is by using DesignModeler.

Synthetic spider web import from SolidWorks

Use the Line from the sketches under Concept, we created a circular cross section with the radius r to be 1 mm. After that we choose the Cross Section in the Line body to be Circular 1 and we open Mechanical.

In Mechanical, first I encountered the problem of Contact type. How to set the contact type between different threads? Since there are many contact types that I will set, I quickly search for other faster way to solve it. Later I solved this problem by using the method written in article Ansys Model Analysis Share Topology Issue, feel free to take a look.

Set the boundary condition to be remote force to better capture when the web encounter loading [1]
Total deformation in ANSYS Mechanical

After setting all the boundary conditions, including fixed support at each ends of the threads and remote force (1000N) at the center of the web, we get the Total deformation to be 544.8 mm at the center of the web.

Then, how could we optimize the spider web? In this project, I change the thread’s radius to minimize the deformation. Yet, it would be an interesting topic to discuss optimize the web’s layout.

Different silk types [4]

In order to optimize the radius of the threads and the deformation at the same time, we could set the deformation in Mechanical and radius in DesignModeler as parameter and open Parameter set to optimize.

After solving the parameter sets, we could import the data into Excel and derive the relationship between thread’s radius and deformation. As we can see, the slope quickly flatten and almost smaller than 100 mm once we increase the circular radius above 1.5 mm.

Deformation trend

To be noted that, if we want to converge to a certain deformation we could use Direct optimization in ANSYS.

Thank you for reading this article and if you are interested or have any question regarding, feel free to contact me!

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