vibration measurements car

Automotive - NVH Testing

Noise, Vibration and Harshness (NVH) is the study and modification of noise and vibration characteristics particularly in cars and trucks.  Optomet Laser Doppler Vibrometry is used in many NVH testing applications within the Automotive Industry.  Original Equipment Manufacturers (OEMs) utilize scanning laser vibrometry for measurements on full scale body-in-white vehicles to validate and update Finite Element Models (FEMs).  Subsystem and component level testing also enjoys the benefits of LDV.  For example, OEMS and suppliers of braking systems routinely use LDVs to address brake squeal issues, verify supplier components meet Frequency Response Function (FRF) design specs and perform production line testing.  Even sub-suppliers of automotive electrical components utilize LDV to solve failures on printed circuit boards or other products that arise out of Highly Accelerated Life Cycle (HALT) or Durability Testing.  Automotive Suppliers perform a great deal of LDV testing to characterize shim (damping) materials to offer the most effective solution with a particular program’s budget and weight constraints.  As Noise, Vibration & Harshness (NVH) targets a passed down to suppliers for OEMs, suppliers are now required to conduct production testing to meet vibration specs.  Optomet Laser Vibrometers are ideal for production QC applications where NVH is now a part of acceptance specifications.

Haptic Displays

In the age of tablets and smartphones, we have long become used to swiping instead of typing. However, many users find it difficult to type on virtual keyboards because they cannot see through their fingertip which point on the touch screen is being touched.

Safety issues arise when touch-sensitive displays are used during the operation of a vehicle. One solution is haptic displays which make keys and slide controls physically perceptible on the display. They provide tactile feedback to a user’s finger during the execution of his or her commands without the need to look at the screen.

Optomet laser Doppler vibrometers are indispensable tools during the development of such haptic displays as well as for their quality assurance in production.

Electric Drives

Modern cars have many electric drives built in, some of which are in the direct area of perception of the occupants of the car, such as electric windows, electric sunroof, servo motors for outside mirrors, wiper motor or seat adjusters. Other drives operate without being perceived directly, such as fuel and coolant pumps or blower motors.

Beyond their desired function, these drives an also be a source of objectionable noise. Such extraneous noise can become clearly audible, especially in electric or hybrid vehicles where the combustion engine as one of the main sources of noise is eliminated.

Laser vibrometers from Optomet are ideal in assisting design and test engineers in localizing, visualizing, quantifying and eliminating such sources of undesirable noise. 

Brake Systems

Optomet’s SWIR Laser Vibrometer technology is ideal for automotive brake system and component testing.  The distinct advantage of OptoMET’s solution over traditional HeNe based systems is most clearly demonstrated during measurements on the friction surface of rotors on a brake dyno.  Back to back testing of SWIR and HeNe vibrometers has proven the inability of HeNe to produce quality data due to excessively high data noise levels.  These high noise levels mask the resonances engineers seek to investigate.  OptoMET’s SWIR technology produces dramatic results in these applications with noise levels 40dB to 50dB below the peak amplitudes of resonances which makes it the clear choice for engineers who wish to characterize rotor dynamics.  OptoMET’s scanning laser vibrometry can be utilized during dyno testing of brake systems to characterize caliper and rotor behavior.

Automotive acoustic comfort

In automotive development, special attention is paid to vehicle cabin acoustics, which means that noise and vibrations should be effectively suppressed. However, since the sound-absorbing materials such as foam or rubber used on the body increase the weight and the cost of the vehicle, engineers look for options to optimize the amount and placement of the sound-absorbing materials.

Operational vibration analysis visualizes the deformations of the vibrating system or component. Noise-reducing measures are most efficient in zones of maximum displacement and largely ineffective at the vibration nodes. Since the attached accelerometers would falsify the measurement due to mass loading of lightweight parts, OptoMET SWIR scanning vibrometers are used to visualize the vibration modes while avoiding the issues typical of conventional sensors.

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