What is Finite Element Analysis (FEA), why do we use it and, what are the benefits for product and medical device development?

Chartered Design Engineer, Jack, discusses how FEA can support the New Product & Medical Device Development Process…

 

What is FEA and why use it?

When designing a new product or medical device, having the ability to make prototypes means issues can be identified early in the process. However, not all projects have this luxury so must be right first time – a challenge we’re used to seeing!

Many of the projects we deliver must be right first time, whilst incorporating challenging mechanisms and structures as well as a variety of materials. So, how do we overcome this challenge?

Doing hand calculations can be used for simple components but once you start combining multiple materials and complex mechanisms, they become limited in their usefulness. This is where Finite Element Analysis or, FEA, comes in. FEA allows you to build a computer simulation of your component, product or device that can be ‘virtually’ tested in the same manner you would a physical prototype. It does this by taking a CAD model and breaking it down into a finite number of elements which can then be analysed individually. A typical FEA model will have thousands of elements which make up a mesh that closely resembles the original components physical form.

Here at HD, we provide cost effective FEA services by using simulation software to optimise and verify our designs, and those of our clients too. We identify, then calculate load scenarios and conduct motion analysis of designs to ensure they conform to specified performance requirements. By using SW Simulation software, we will provide you with results for deflection, stress and strain. We also use SW Simulation for computational fluid dynamics and thermal analysis.

What are the benefits of using FEA services and simulation software?

By using FEA throughout the process, it is possible to greatly reduce development times. Creating 2D and 3D models and quickly running load case scenarios ensures components are correctly selected/sized and the overall design meets the product specification – before anything needs to be physically manufactured. This saves time and money by eliminating numerous loops of prototyping and testing. One key advantage of using HD for your FE Analysis is that we interpret results to provide practical design advice and guidance to overcome issues identified in the process.

We’ve optimised many designs and used simulation to:

• Reduce component weight

• Improve rigidity / flexibility

• Reduce stress concentrations and thus improve fatigue performance

• Reduce costs by utilising thinner / less materials

• Allow lower grade, lower cost materials to be used

• Ensure products and components are safe

• Improve the sustainability of a project

Using FEA can be hugely beneficial to a project as it will typically reduce costs, save time and improve product performance. Further FEA advantages are lower environmental impact by using reduced material usage for optimised rigidity / flexibility / weight. Effective use of FEA throughout the process will ultimately ensure your design is fit for purpose.

 

Here’s a quick explanation of the different types of analysis that can be utilised:

 

Linear & Non-Linear FEA:

Materials can either be linear elastic (where the relationship between stress and strain in the material is linear – for example aluminium or steel), or non-linear elastic (where the relationship between stress and strain in the material is non-linear – such as in polymers). Linear elastic materials are typically linear up to a point, and then start displaying non-linear elastic behaviour beyond it.

Linear FEA is carried out when a part is made from a linear elastic material, and there is not excessive deformation caused by the forces being applied to the part. Where the material is non-linear elastic or the forces being applied can cause large displacements, a non-linear FEA must be performed instead.

Our advanced Non-Linear FEA software ensures plastics can be thoroughly analysed, allowing designs to be finely tuned and verified for high volume manufacture and ultimate performance. With plastic waste currently a hot topic, Haughton Design can analyse designs and then provide advice or redesign the product to reduce weight and material volume to lower environmental impact and material usage. Where material properties are available, we can test sustainable alternatives too.

Static FEA:

A linear static FEA is performed when the forces applied to a part or assembly do not change over time. A static FEA is the simplest form of FEA, and is performed exclusively on linear elastic materials, where small displacements are anticipated.

 

Dynamic FEA:

A dynamic analysis is performed when the forces applied to a part or assembly change over time. A dynamic analysis can be performed on either linear elastic or non-linear elastic materials. Common examples of a dynamic study include drop tests and vibration analysis.

Thermal Analysis:

Thermal analysis simulates heat transfer between solid bodies. A thermal analysis can be a useful standalone tool, for example when analysing the design of a heat-sink. It can also be used in combination with a static analysis to conduct thermal stress analyses on parts or assemblies.

 

CFD – Computational Fluid Dynamics:

CFD simulates how gasses or liquids flow in, or around, a part or assembly. It is frequently used to analyse air flow through a design and optimise external forms to reduce drag or to provide directional force to the structure such as to increase downforce on high-speed vehicles.

Potential issues with FEA:

A frequent issue with FEA is that the original load cases and loading scenarios are incorrect so they don’t truly represent the actual load onto a component or system. We’ve found this risk can be reduced by taking the time to truly consider what is happening and using SW Simulation to identify peak loads and understand loading profiles.

One of the biggest issues we find with FEA being outsourced, is that the iterative nature of design optimisation can be broken or come too late. It’s typical for analysis to identify issues in a design, which subsequently require further investigation and design optimisation. Therefore, it is always an advantage to introduce FEA, as early as possible, into the design process. This means problems are identified more quickly and changes can be made to the basic design early on. Doing this well before extensive engineering is undertaken will significantly reduce time and therefore costs or delays.

 

HD offer industry leading FEA Services:

We are a design team who fully understands FEA results and what needs to be done with designs to achieve the outcomes our clients require.

Read about how we recently used FEA and Simulation to study and optimise the performance of an inhalation device.

If you need any advice or guidance on the effective use of FEA to speed up your product or medical device development process, please get in touch and we will be glad to help.

Jack Dunkley CEng 20 August 2021

Share

Get in Touch with Jack Dunkley CEng

Lead Design Engineer

Jack is a chartered engineer who holds a Master’s degree in Mechanical Engineering from Cardiff University. He has experience working with design for injection moulding, machining and sheet metal as well as design for assembly and serviceability. Prior to HD, he worked at metrology company Renishaw for 6 years where he led several complex mechanical projects from initial concepts through to production. He has also worked at electrosurgical medical device manufacturer Olympus Surgical Technologies Europe (Gyrus ACMI).

Get In Touch

Our latest insights

Latest Posts

Route to Engineering Chartership | Lead Design Engineer, Jack

Read More...

How to rescue a poorly managed development project

Read More...

Share