Measurement and analysis of vibration and deformation using laser metrology for automotive application

Abstract

Vehicle quality has become one of the most important factors in customer satisfaction. Of all quality attributes, noise, vibration, and harshness (NVH) are often immediately noticed by customers during purchase trial drives or initial usage periods. High-quality NVH is, however, one of the most challenging attributes to achieve. Vehicle development constraints usually require that other attributes such as safety, durability, functionality, package, weight, and cost be satisfied prior to NVH attributes. Laser metrology has advantages including spatially dense data points and the fact that it is non-contact, non-invasive, and fast. It has become an indispensable tool to provide optimal solutions for achieving high-quality NVH under various constraints. This article focuses on the state of the art and its applications on reducing NVH and related concerns in the automotive industry. Keywords: laser metrology, noise and vibration, automotive INTRODUCTIONis converted to vibratory energy of the brake components, the brake system will vibrate and generate In today's highly competitive automotive market, brake roughness/judder or noise. Brake roughness is customers have high expectations concerning vehicle a low-frequency vibration caused by brake torque quality. Of all quality attributes, noise, vibration, and variation (BTV) at the wheel/brake assembly during harshness (NVH) are often immediately noticed by braking and propagated through the suspension customers during purchase trial drives or in initial and steering. One of the root causes of BTV is purchase usage periods. NVH is one of the items disc/rotor thickness variation (DTV). The challenge shown in JD Power Associates' initial quality survey.is quickly and accurately to obtain a rotor surface Vehicle development constraints usually require that profile with spatially dense data points when the other attributes such as safety, durability, functionrotor manufacturing process capability is being ality, package, weight, and cost be satisfied prior verified. Laser metrology can be used to achieve this to NVH attributes, which makes high-quality NVH goal. Brake noise mainly includes groan, moan, and one of the most challenging attributes to achieve. squeal, with squeal being the most often occurring Of all NVH issues, three of the major sources are noise. Brake squeal is a high-frequency noise and is the noise and vibration from the engine/powertrain generally caused by friction-induced self-vibration system, brake/suspension system, and body panels.[1, 2]. Computer aided engineering (CAE) using a The following examples are taken from vehicle finite element model to simulate brake noise has development/problem solving projects.been greatly advanced recently [3]. However, before Brakes stop vehicles by transforming vehicle kinetic the CAE model can provide a design optimization energy to other forms of energy, such as thermal solution, the model firstly needs to be correlated. energy. However, when some of the kinetic energy One of the correlation and squeal root caus...

Brake comfort – a review

“…In [13,30], many brief reports are given. These methods are used to examine the modes of squealing brakes.…”

“…• SLV (scanning laser vibrometer) is used to identify locations with large amplitudes and is ideal to identify hot spots (for more details see [30]). …”

Concrete damage mapping combining laser scanning vibrometry, dynamic response modeling, and ordinary kriging regression

“…LSV has been successfully employed in engineering research for the evaluation of dynamic behavior and structural integrity of metallic constructional elements like plates and beams, 13,14 rotating machine elements, 15 and aircraft wings 16 . Monitoring of wave propagation in thin metallic plates and their interaction with structural flaws is another essential discipline where LSV method has been effectively employed for the diagnosis of structural damage 17–19 .…”

Transfer behaviours and influences of high-order hot judder in passenger cars

“…During braking, many noises and vibrations in a vehicle can be induced by the braking system; brake squeal, 1–5 moan and groan 6 and brake judder are the phenomena which most commonly occur. Preventing or reducing these noises and vibrations is a major target in the development of passenger cars.…”