Finite Element Analysis (FEA) is a powerful tool used to simulate and analyze the behavior of an object. With electrical contact design, FEA is primarily employed as a mechanical simulation technique. It allows engineers to model the deformation, stresses, and forces acting on electrical contacts under various conditions. Performing FEA shortens product development time, reduces the amount of prototypes, and ultimately, helps ensure the contact will perform as required.

How Does FEA Work?

FEA works by breaking down a complex object into smaller, manageable pieces called “finite elements.” These elements form a mesh that represents the object’s geometry. By applying relevant physical laws and material properties to these elements, engineers can predict how the entire object will behave under specific conditions.

How is FEA Applied to the Contact Design Process?

For electrical contact design, particularly sliding contacts, FEA plays an important role in the earlier stages of development. Engineers start by creating a detailed 3D model of the contact using software like Creo, SolidWorks or Inventor. The 3D model is then imported into FEA software, where they define the material properties, boundary conditions, and loads that the contact will experience.

Sliding contacts serve a simple but important purpose: to reliably and consistently conduct electrical signals. They are typically stamped from precious alloys. As they move, they rub against the mating surface, which causes wear over time. If contact force is too high, the surface or material rubs away too fast and performance is reduced. If the contact force is too low, the electrical connection and transmission becomes weak.  Low contact force also increases contact resistance which could produce noise in the system. FEA helps engineers find a contact geometry with the optimal contact force.

For electrical spring contacts, the primary focus is on mechanical FEA, which simulates:

• Deformation of the contact
• Stress distribution (including maximum and minimum stress locations)
• Contact forces at specific points

Working Position Analysis – One key application is simulating the contact’s behavior as it moves from its free (unlatched) position to its working (assembled) position. This helps ensure that the contact force at the contact point is within the proper magnitude, typically targeting 2-5 grams of force per contact point for low energy applications.

Stress Optimization – Engineers use FEA to minimize stresses throughout the contact, ensuring that no part experiences high stress that could cause yielding during assembly or over time.

Temperature Considerations – While FEA assumes that parts are operating at room temperature environment, the results can be used in conjunction with stress relaxation curves to predict performance at different operating temperatures.

Contact Design Challenges and Considerations 

FEA addresses several other critical considerations and challenges in electrical contact design, including:

Wear Prediction – While FEA doesn’t directly measure wear, it provides crucial data on contact forces and stress distributions that may be used to inform wear estimates.

Stress Distribution Visualization – Unlike simple hand calculations that might only provide maximum stress values, FEA generates detailed stress contours. This allows engineers to identify and address areas of high stress concentration.

Design Iteration – FEA enables rapid iteration on contact designs. Engineers can quickly test various material thicknesses, contact blade profiles, and shapes without the need for physical prototypes at each stage. This helps shorten the product development process and reduce development costs.

Material Selection – By providing accurate stress estimates, FEA helps in defining materials and process requirements, such as cold working or heat treating, for the contact’s service conditions.

Temperature Performance – When combined with material-specific stress relaxation data, FEA results can predict how contacts will perform at different operating temperatures over time.

Manufacturability – Early-stage FEA allows engineers to design around manufacturing capabilities, ensuring that the final product can be produced efficiently and to the required tolerances.

Better Contact Designs, Quickly & Efficiently

By leveraging FEA in the early stages of electrical contact design, engineers can:

• Quickly eliminate unfeasible designs
• Reduce the time and cost associated with physical prototyping
• Improve the overall quality and reliability of the final product

In conclusion, FEA has become a critical tool in the electrical contact design process. It provides valuable insights that guide design decisions, optimize performance, and ultimately leads to more reliable and efficient electrical contacts across a wide range of applications.

Can you benefit from FEA for your contact designs? Contact one of our application specialists today to discuss your requirements.