Hi SIMULIA Community!
Do you remember your first simulation project that wasn't dictated by a textbook or coursework? My FavoriteSimulation (and maybe yours too) falls into that category.
Here is an image of the results. Any ideas what it could be?
If you guessed it's a structure found in nature you are on the right track.
If you take that and the fact that "My favorite simulation is very Hip", you may be even closer.
One final hint in the form of an image:
This little critter is a shrew, one of the smallest species of mammal in the world.
Now the big reveal:
My favorite (and first) simulation project is a structural analysis of the shrew hip bone; more specifically, it is a plane-strain Abaqus analysis of the sagittal section of the proximal portion of a shrew's femur (that's the top of the thigh bone that connects with the pelvis to form the shrew's hip joint).
Why would anyone want to simulate a shrew femur?
The goal of the project was to explore the relationship between the form and function of trabecular tissue, a.k.a spongy bone. When you look at the trabecular tissue of the top of a human femur you see clear patterns; check out this image of a human femur from a paper published on ResearchGate. As a mechanical engineering student at Brown University with an interest in biology, I was curious to discover what simulation could reveal about how the patterns in trabecular bone tissue relate to bone performance. This was more than 20 years ago, and back then the complexity of human trabecular bone geometry far exceeded the capabilities of the scanning, digitization, and meshing technology available.
Professor Sharon Swartz had a creative solution to this challenge … go small! Her research had shown that trabeculae, the tiny pieces that make up the sponge-like trabecular bone structure, don’t scale proportionally with animal size*. Therefore, if we study the bone of a very small mammal, such as a shrew, the number of individual trabeculae that fit under the hip join are few. This reduces the complexity of the shrew's bone geometry making it possible to digitalize, mesh, and simulate at a cross-section of the bone.
* Swartz, S. M., A. Parker*, and C. Huo*. 1997. Theoretical and empirical scaling patterns and topological homology in bone trabeculae. Journal of Experimental Biology, 201:573-590.
What does the simulation reveal?
In the simulation result plot, you can see that when the femoral head of the shrew hip is loaded (the top left protrusion in the image), the load is fairly evenly transferred through the trabecular structure at the top of the bone, closet to the joint. There is, however, significant bending (and consequently high strain magnitudes in blue) in the lower portion of the femoral head where there are fewer supports.
Many thanks to Prof. Sharon Swartz an inspirational teacher, mentor, and head of the Brown Unversity Aeromechanics & Evolutionary Morphology Lab.
Links
Interested in biology, engineering, and simulation? Check out these posts:
I look forward to reading your favorite simulation story!
