5 uses for Finite Element Analysis (FEA)
1. You need to know if your idea is feasible
Also known as ‘quick and dirty FEA’, some engineering analysis can help when you need to know if you are in the right ballpark for a concept you’ve come up with. At this stage the medical device design is not yet refined – you just want to know if it will likely fail under its intended loads/deflections. This doesn’t have to be an extensive piece of work either. For example, a simple model can be set up and run within a few hours, giving you the ‘go ahead’ or the ‘no go’ required for continuing with your design.
2. Your hand calculations might be over simplifying the problem
Hand calculations are often the first step in the analysis but can frequently become over complicated with non-linear materials and complex geometry. This can open up opportunities for unrealistic values in your calculations. A quick FEA can be used here to check your calculations. The analysis might suggest that your calculations are close and you can go ahead and use them, or you might find that you’re out by too much. In the latter case, a further FEA is required to really model what’s going on.
3. You need to quickly compare several design options
Following a brainstorm, let’s say you decide there are three main options for a design and there are pros and cons for each in terms of simplicity, manufacturability and functionality. You then need to know which option will be the strongest so that you can select the optimum design. Because you are directly comparing the options there may be less need to get your material model spot on. You can use FEA to directly pit the designs against each other, looking for areas of weakness.
4. You want to know if your design is robust
Within medical device development, an understanding of the key dimensions/parameters that can impact intended performance is vital for ensuring a robust and reliable design. Often, a robust design can perform as intended even when the design doesn’t look like it does on your CAD software. For example, in reality, your modelled design could be at geometrical tolerance limits and impacted by temperature or other environmental influences. The design is also likely to be susceptible to changes in certain parameters more than others.
An FEA sensitivity analysis can be used alongside Tolerance Analysis to identify where these susceptibilities lie within the design. This can be done parametrically, without the user creating lots of individual models, meaning you can let it whir away in the background while you get on with the rest of your to-do list.
5. Sometimes, you can’t easily test real parts
COVID-19 is a good example – the pandemic has brought several restrictions to working practices, whether that’s due to laboratory access, supplier delivery times or personal circumstances. As designers and engineers, we must select the most efficient method for assessing our designs. Depending on your circumstance, it may be that FEA is a more favourable choice while restrictions are in place. Obviously, it cannot and should not replace empirical testing, but rather work alongside it to ensure that we use our time and resources appropriately.
