Simulating noise and vibration environments is key for successful product operation.

Successful product development requires simulation of complex environments in which the product must operate. Design, validation, and qualification engineering groups must perform these simulations to validate new products as well as to validate performance and optimize existing designs.

This article describes several challenging environments that must be simulated including space launch, vibration, and acoustic environments. Space launch environments are the extreme sound levels that space flight components are subjected to during the launch phase. These sound levels can reach 160 dB during a typical launch (Figure 1). Vibration occurs in every product’s lifecycle and can be the source of failure or defects. Vibration environments are used to simulate product operating conditions or for simulating a lifetime of operation. Acoustic environments are found wherever humans encounter sound due to their surroundings. The sound must be simulated and evaluated to increase the enjoyment of the product or to ensure the safety of the person in that environment. Each of these simulation environments will be described along with the techniques used to create the simulation.

SPACE LAUNCH ENVIRONMENTS
Space flight has yielded many benefits since man has ventured outside our atmosphere. These gains have come with significant risk and many challenges. To develop and field a space launch vehicle requires the combination of many disciplines and technologies. One of these technologies is the simulation of the acoustic environment which is created as the space vehicle is in the take-off portion of the mission. During this time the noise caused by the rocket engines is extremely loud. Sound pressure levels measured from typical launches range from 130 dB to 160 dB. Experience has shown that this high sound level can cause physical damage to sensitive components. When those damaged components are expensive space instruments, such as satellites or flight components required for safe operation of the vehicle, failures are not an option. The sound levels of a launch are simulated in a laboratory to allow designers to fully subject the components to the environment they must survive. To simulate the launch environment, the same levels of sound pressure must be duplicated along with the frequency content of that sound. Measurements from test and actual launches have been used to develop profiles which describe the environment in terms of sound level and frequency based in a 1/3 octave band graph such as the one shown in Figure 2.¹