Plextek Limited is one of the largest independent electronics design consultancies in Europe, specialising in product and system design for communications, automotive, aerospace, defence and medical applications. Wilde was asked to assist Plextek with selecting materials suitable for a plastic enclosure used to protect electronic hardware.
The two-piece case carries an internal PCB and battery pack sealed and supported using an elastomer material. During assembly an assessment of the structure was conducted to ensure the compression of the seals and buffers did not impart excessive deflections and stresses into the case.
ANSYS FEA software was used to simulate the assembly process as the plastic enclosure was closed and the elastomer seals and buffers compressed. The high percentage of seal and buffer compression resulted in a challenging analysis, requiring control over the quality of the initial mesh and the analysis algorithms chosen to achieve a successful solution. Appropriate hyperelastic material models were assigned to capture the compressive behaviour of the elastomers. Interfaces between components were captured through contact conditions including friction.
Wilde quickly understood the scope of the analysis and defined precisely the engineering information that would be required from Plextek to allow the work to proceed. The product design was modified on the basis of the analysis. Samples subsequently passed rigorous environmental testing including vibration and drop testing before the design was released for high volume production.