June 15, 2020
Engineers tend to spend a lot of time tweaking and simulating a design to optimize its look, feel and performance. However, they should not underestimate the sounds made by their products by addressing them late in the development cycle.
Engineers can design the best dishwasher in the world. But if its too loud, or too quiet, people may not think it’s working properly.
The perceived quality that sound gives a product can be positive as well. We all wait in anticipation for the pop of a toaster, the snap of a seat belt or the click of a connector. In fact, these sounds are so satisfying that it’s common to hear them in commercials.
On the other hand, a bad sound could be disastrous to a product. Imagine a ceiling fan that cooled a room in seconds but sounded like a helicopter — no one would buy it.
Since sounds can impact product sales, it could be problematic if engineering teams use the traditional method of waiting until physical prototyping to listen to their design for the first time. At this stage of the development cycle, it could be too costly to fix the problem.
What if you could just listen to your product’s sound during the design stage of development? Yes, you can by using acoustic simulations. In fact, companies have started to create whole departments that focus on optimizing product sounds.
Before we dig into how to listen to a simulation, let’s discuss where these sounds come from.
Products that contain vibrating parts, impacting components, fluid flows and electromagnetic fields can all produce sound by vibrating the air, or medium, around them. So, to simulate the noises that products make, you must first simulate their functions.
For instance, to simulate the sound inside a car, you must model the wind that brushes past it and the vibroacoustic behavior of the powertrain. Even the sounds of an air conditioning system are important for quieter electric vehicles (EV).
Once the product operations are modeled, all of these noises can be identified and studied for their sound level and quality. The levels can be calculated in decibels, a unit of sound that measures its pressure, power and intensity.
However, it’s harder and subjective to assess sound quality. Psychoacoustic indicators like loudness, sharpness, roughness, tonality and fluctuation strength can estimate the sound perception. However, to get an accurate rating of sound quality, engineers need to conduct listening tests with groups of people and statistical analysis. As sound quality is subjective, the best way to judge it is for each person in the test to listen to it.
That is why acoustic simulations are so important: They can help design the functional aspect of a product and its sound as well..
Let’s say you want to assess the noise of an electric vehicle. The major components of the powertrain that contribute to the product’s sound are the motor and gearbox. So, to assess the sounds you first use multiphysics workflows that simulate these systems.
For instance, engineers could simulate a car’s dashboard and compare how light from external headlights, readouts, windshield reflections, mirrors and radio can all affect the driver’s vision. These simulations can be tweaked to assess how the driver’s ages or visual impairments could affect the results.
With age, people tend to become more sensitive to glare. They also tend to perceive certain objects with a yellowy tint. Age will often stiffen an eye’s lens, causing close images and writing to appear blurry. SPEOS can simulate all of these effect within its human eye model. The human eye model can also be tweaked to test color-blindness and other visual impairments.
Based on this information, engineers can improve driver safety by iterating the color, shape, brightness, glare or (when applicable) fonts of the:
Motor and vehicle sounds aren’t the only noises engineers need to optimize. As a result, Ansys offers multiphysics simulation workflows that can be used to model the noises of various products.
For instance, fans, compressors, pumps and blowers can be simulated using Ansys Fluent. The CFD software can be used to perform an aeroacoustics simulation that takes into account blade performance and turbulence. This data can then be passed onto VRXPERIENCE Sound to get a 3D sound rendering for people to listen to. Then engineers can assess and optimize the sound quality based on this virtual model.
Many rotating machines need to adhere to aeroacoustics standards. With acoustic simulations, engineers have a cost-effective way to generate the noise of their designs and ensure they are appropriate.
Designing the sounds of consumer goods is just as important as designing them for industrial products. For instance, no one wants a silent golf club. They want the satisfying snap of impacting the ball without the thud if they hit the dirt.
So, depending on the context, the sounds of impacts can be both desirable and undesirable. By simulating the products, engineers can minimize undesired sound and enhance the ones they want to embellish.
For golf clubs, the sound will depend on the impact’s velocity and shape. But it’s also dependent on the materials of the impacting objects and the media they are in. This can be a challenge to physically test and manually design, but with Ansys LS-DYNA and VRXPERIENCE Sound, engineers can ensure that a golf club has a good smack when it contacts the ball and is nearly silent when it hits the ground.
We’re here to answer your questions and look forward to speaking with you. A member of our Ansys sales team will contact you shortly.