Like many engineers, I often wonder if there is a better way to accomplish the tasks I am working on and how I might design a model that meets all the requirements more efficiently. One of the many ways you can pursue this quality of work is through topology optimization.
You may have seen components of products that you use every day that has material removed and holes in very strategic locations, or you may have noticed thickened and buffeted regions with greater structural strength. These parts tend to look incredibly organic and natural, so it begs the question, how did this get designed?
The answer is topology optimization!
What is Topology Optimization?
In a nutshell, topology optimization is the process of identifying and removing regions of a component that do not significantly contribute to the part's ability to meet performance goals. In other words:
"Topology optimization has been used by mechanical and civil engineers for many years, in order to minimize the amount of used material and the strain energy of structures while maintaining their mechanical strength." (Bendsoe et al., 2003)
One of the primary things designers will notice about topology optimized models is that the shapes and structures can be incredibly complex and organic, almost organic in nature, beyond anything a designer would jump to as a first option.
This shape is a direct result of the Finite Element Analysis approach, which is to say that the entire volume of a component is translated into tetrahedral elements, allowing the strength equations and solvers to calculate stress and various material properties of any and every finite element of the volume.
Based on this data, any single element or region of the component could be removed if it does not contribute to the overall capability of the model. This gives the software more variability and data-backed reasoning to alter a part than would be available to the average designer.
The analyst can then further constrain this information and focus on the purpose of reducing mass, minimizing deflection, or managing resonant frequencies. All of this can be done while preserving strength properties and preserving the factor of safety.
When to Consider Topology Optimization
The very nature of optimization means that the resulting part will have material removed thus sacrificing strength and stiffness. A component that is already pushing the limits of its strength risks failing if too much material is removed. An initial study of the base part is required to ensure the component can be optimized at all.
In addition, a part that already has thin walls and detail features will not have sufficient volume to remove material from. A part used for topology optimization should occupy the maximum space available. The more space the study has to evaluate, the more optimized a shape it can produce.
Topology optimization is critical in manufacturing. Knowing the chosen fabrication process at the beginning will allow the user to take steps to ensure production of the final shape is still possible. Here are a few key elements to review in this process:
- The initial part should be larger than the final desired component
- Stress in the initial part should not be too high
- Understand manufacturing limitations
When developing the initial shape, analysts can simply run a study on an existing part, or the study can be run on a representative bounding volume which represents the maximum design space. The most important thing to account for in a design is the critical mounting locations. In the following example, we have a bracket that is fixed in two locations (green) and has a vertical load applied on the remaining location (purple).
After applying the appropriate loads and fixtures, you can make a few additional considerations such as:
- Optimization Goals
- Shape Constraints
- Manufacturing Controls
After our study is complete, we can inspect the final shape. The shape is now ready for additive manufacturing or parametric design. We will cover the simulation study steps and manufacturing considerations in later follow-up blog articles.
Read our in-depth white paper on using these dynamic tools available in SOLIDWORKS so that you can use topology optimization to design components with manufacturability in mind right from the start, regardless of industry!