NVH
NVH is an industry term that stands for noise, vibration and harshness. It is initially the study and modification of the noise and vibration behavior of vehicles, and has been extended to the analysis and research of the dynamic behavior and performance of any mechanical system with vibration and noise targets or issues.
Noise, including structure-borne and airborne noise, is unwanted sound, vibration is the oscillation that is typically felt rather than heard, and harshness is generally used to describe the severity and discomfort associated with unexpected sound and/or vibration, especially from short duration events. For example in the automotive industry, harshness is approximately defined as a combination of noise and vibration above 25 Hz, which results in a hard-tire sensation.
The analysis content covers Normal modes, Operating modes, Mode participating factor (MPF), Point mobility(NVH sensitivity), Frequency response function (FRF) for actual excitations, Sound pressure level(SPL) , Abnormal noise analysis (Squeal & Rattle), etc.
MODAL ANALYSIS OF A CRANKSHAFT SYSTEM
In a specific NVH analysis implementation process, a corresponding high quality finite element model which reflects the NVH behavior characteristics for the analyzed objective, conforms to the actual constraints, and is applied for dynamic loads is fundamental, and then a proper and efficient solver such as NASTRAN, ABAQUS or SYSNOISE for simulation will be used.
Based on the analysis results combined with the frequency range, NVH sources, operating conditions of the NVH system (for instance, a full vehicle or a set of air conditioner), a solution to effectively meet the customer analysis requirements can be proposed.
Generalety has been proficiently and efficiently carried out NVH analysis and research for more than ten years using CAE simulation technology. Our clients from different application fields include the automotive industry, the metallurgical industry, rail transit equipment, industrial and civil construction, construction machinery, HVAC, powder chemical vibration equipment , internal combustion engine manufacturing, and many others.