Browse Topic: Vibration
Inverters are typically integrated into electric drive units for electric vehicles (EVs) to reduce packaging size and cost. However, coupled vibrations from the electric motor and gears are transmitted to the inverter, which can become a dominant noise source due to its large radiative panel. Metal panels are required for electromagnetic interference (EMI) compliance, yet these covers usually lack sufficient stiffness or damping for noise control. Adding ribs and applying damping treatments result in excessive mass, cost, and packaging challenges. A new bubble sheet panel design has been developed to enhance the structural strength and damping performance of the inverter cover while significantly reducing its mass. A thin sheet of aluminum is welded onto the cover in an optimized pattern that enhances stiffness and damping performance while accommodating packaging requirements. The welding pattern can include logos or artistic designs to improve the panel’s appearance. The metal sheets
Nowadays, customers expect excellent cabin insulation and superior ride comfort in electric vehicles. OEMs focus on fine tuning the suspension system in electric vehicle to isolate the road induced shocks which finally offers superior ride quality. This paper focuses on enhancing the ride comfort by reducing the road excitation which originates mainly due to road inputs. Higher steering wheel vibration is perceived on the test vehicle on rough road surfaces. To determine the predominant force transfer path, Multi reference Transfer Path Analysis (MTPA) is performed on the front and rear suspension. Based on the finding from MTPA, various recommendations are explored and the effect of each modification is discussed. Apart from this, Operational Deflection Shape (ODS) analysis is used to determine the deflection shape on the entire steering system . Based on ODS findings, recommendations like dynamic stiffness improvements on the steering column and steering wheel are explored and the
This paper focuses on the cabin sound quality refinement and the tactile vibration reduction during horn application in the electric vehicle. A loud cracking sound inside the cabin and higher accelerator pedal vibration are perceived while operating the horn. Sound diagnosis is carried out to find out the frequencies causing the cracking noise. Transfer path analysis is conducted to identify the nature of noise and the predominant path through which forces transfer. Based on finding from TPA, various recommendations are evaluated which reduced the noise to a certain extent. Operational Deflection Shape (ODS) is conducted on the horn mounting bracket and on the body to identify the component having higher deflection at the identified frequencies. Recommendations like DPDS improvement on the horn bracket and the body is assessed and the effect of each outcome is discussed. With all the recommendations proposed, the cabin noise levels are reduced by ~ 8 dB (A) and the accelerator pedal
Powertrain is the most prominent source of Noise and Vibration in the vehicle. Improvement in Powertrain Noise and Vibration is a multifaceted topic due to the complex architecture of the powertrain and the critical role of calibration in defining combustion inputs. Hence, a method to clearly distinguish these aspects is required in order to address the exact problem and decide on course of actions to improve NVH performance of powertrains. This paper discusses a post-processing technique through which experimentally acquired ICE Powertrain Noise can be further segregated in order to identify and address the root source. The segregation methodology requires as input - noise, vibration and cylinder pressure values at various torque conditions across multiple operating points. A MATLAB based code developed by the authors is used to generate correlation between the Cylinder Pressure, Torque and Noise Parameters. The transfer coefficient at every frequency point is calculated using
One of agricultural tractors most important aspects is operator comfort. In addition to working long hours, tractor operators may be at risk for health problems due to vibrations and mechanical shocks. The tactile vibrations of a tractor are a major consideration when choosing one for agricultural use. This project's mandate includes a study of tractor vibration control problems. It is essential to investigate the governing system in order to determine the cause of the problem. Evaluating the vibrations transmitted via the tractor and using the design of experiments (DOE) approach to lessen vibrations on particular tactile regions were the study's goals. There are several measures currently under investigation which can be used to reduce the vibrations caused by resonance in this paper, these include reducing the natural frequency so as to be able to avoid resonance with the second order engine frequency and the damping coefficient; this will ensure the amplitude of vibration at
The effective measurement and verification of dimensional stability indicators for large size and highly stable structures in service environments is the key to the development of high-precision spacecraft technology. Spatial carrier speckle interferometry technology has been widely used for high-precision measurements in recent years due to its advantages of fast speed, high accuracy, and simple operation. However, the existing technical research only focuses on the measurement under normal temperature and pressure environments, and there is little research on the application under complex operating conditions in space. There is currently no relevant research on the impact of system ambient vibration and noise on measurement stability disturbances. In response to the above issues, a high-precision deformation measurement system suitable for complex environments of high and low temperatures in a vacuum was designed based on spatial carrier measurement technology. A system measurement
According to a problem of the vibration and noise suppression of an engineering vehicle cab, a dynamical model of the engine-frame-cab system was established to describe the vibration transmission path. The method of calculation of the vibratory power flow, which is transmitted from the vibration source engine to the cab through the frame and isolators, was deduced. And then an optimization strategy for the frame structure and the corresponding analysis algorithm process were proposed based on the objective function of power flow. The method proposed was validated through an application to a practical example, which would have practical value in the field of vehicle vibration reductions and optimization design of frame structures.
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