These slides were presented at the NAFEMS World Congress 2025, held in Salzburg, Austria from May 19–22, 2025.

Abstract

Simulations for predicting acoustics emissions from impulsive and transient dynamic phenomena emerging from small electro-mechanical components, as those commonly found in consumer electronics, remains both novel and challenging. Some of these components act as direct Human-Machine Interfaces (HMIs) between users and the devices being operated. One of such applications are microswitches embedded in computer mice. Besides the functional operation of the device, they also double as the primary source of both tactile and acoustic feedback to the user upon clicking its keys. The afforded feedback is a complex array of multimodal sensorial cues and includes fast transient events such as impulsive phenomena. From a component level to the integration at system architecture, both the acoustic emissions and mechanical behavior of such components constitute the main source of User Experience (UX) for mouse clicking. Predicting, through simulations, the vibro-acoustics performance of microswitches and its integration in the product, in this case a computer mouse, can enable design practices to emerge with better experiences, including addressing potential sound quality issues at earlier stages of product development. Recent advancements in simulation software and improved computational resources open up the possibility of modeling increasingly complex vibro-acoustic phenomena. The goal of this research is to understand current capabilities of simulation software to accurately predict such phenomena. This work aimed at modeling the full simulation of the vibro-acoustic response of a microswitch at the component level. This included the full operational cycle, namely the closure (push) and opening (release) switch events. This paper reports the simulation methodology adopted, from the structural and transient analysis to the acoustic radiation emerging from the component. Structural simulations involved driving pre-stressed Finite Element (FE) models with adequate and experimentally known input forces. A time-domain explicit FE simulation modeled the rapid displacement and buckling of the internal components upon operation for the full cycle. This model was experimentally validated with high-speed footage and positioning tracking of the moving switch elements under real operation conditions. The simulation analysis further explores the model'™s vibration response of the mechanical system across a range of frequencies meaningful to human hearing. Derived from these structural vibrations, sound is generated from the rapid displacement of the fluid (air) surrounding the structure. The acoustic propagation is thus simulated by modeling both the internal cavities of the switch as well as the surrounding air volume for its casing. In order to enable a better efficient use of computational resources, a hybrid mesh was adopted using both FE and Boundary Element Methods (BEM). Experimental audio recordings of switch samples'™ emissions were also used to compare and validate the model. It was found that fine-tuning the simulation model parameters such as damping and material properties is essential in order to accurately reflect the physical behavior. This includes sound quality metrics in both time and frequency domains as well as auralizations. The output results from the simulation can match both the spectral and time-domain characteristics of real audio within a standard measurement error. This study found validity in the simulation methods adopted and its results. It proposes and emerges with a methodology to simulate complex vibro-acoustic phenomena in similar and other applications. Overall, this paper also provides and reports a state-of-the-art perspective on the current vibro-acoustic simulation capabilities available to academia and industry.