Research on the effectiveness of the time shutdown of the damper to improve vibroisolation

Ensuring the reliability and durability of machinery and equipment, and above all, protecting people and the environment from the damaging effects of generated vibrations. This requires the use of effective methods and measures to counter their formation or spread. The vibroactivity of a machine (device) treated as an object can be changed in two basic ways. Parametric or structural modifications can be made. This study investigates the effect of on off temporary of shock absorber on vehicle suspension for vibration isolation

Simulation studies of a shock absorber model proposed under conditions of different kinematic input functions

The paper presents the results of simulation research of visco-elastic model of shock-absorber. Tested shock absorber has been in the suspension system. The aim of research was determine values of force of damping for different kinematic input functions. The results are presented in graphical form that allows for their analysis

Identification of the parameters of visco-elastic model of the hydraulic vibration absorber

The paper presents the results of visco-elastic dampers. Their aim was to determine the parameters of dynamic models. A key issue in modeling is to determine the acceptable degree of simplification. According to the authors diagnostic models must take into account characteristics such as nonlinearity and asymmetry damping characteristics. Also, it is important to take into account the apparent elasticity of the hydraulic damper. Sample parameters of dynamic models of automotive shock absorbers are presented in graphical form

Mobile analysis of railway traffic safety

The paper presents a universal and extremely simple method for studying railway traffic safety, which enables the measurement of safety-related aspects to be conducted with reference to both infrastructure and rolling stock at the same time. The method proposed in the article is an attempt to face up to the challenge of the aforementioned constraint, enabling measurements of characteristics of the railway line infrastructure and of the rolling stock by means of common accelerometers installed in mobile phones. Result obtained illustrates accelerations recorded in three axes. Studying average characteristics for the same train set, one can reveal anomalies related to the track or the rolling stock condition

Simulation of a visco-elastic damper based on the model of the vehicle shock absorber

This paper presents results of simulation of visco-elastic dampers based on the model of the vehicle shock absorber. The aim of this research is to determine the parameters of dynamic models of special dampers applicable in advanced vehicle suspension systems. One of the key issues of modeling is to determine the acceptable degree of the simplification. Model reduction is based on the determination of the damping coefficient suitable for testing vibration control systems. The diagnostic model of the shock absorber takes into account features such as nonlinearity and asymmetry of damping characteristics. It is also important to take into account the apparent elasticity of the hydraulic damper. Damping and stiffness characteristics of automotive shock absorbers are identified by the proposed algorithm. The obtained results proove that the resulting damper stiffness is an important factor which cannot be neglected at higher frequencies of cyclic load

Application of the discrete wavelet transform and probabilistic neural networks in IC engine fault diagnostics

Around the world are continued attempts to use the vibroacoustic phenomena for purposes of diagnosis of machine condition. Particularly important becomes non-invasive methods including methods based on vibration and acoustic signals. Vibroacoustic phenomena, which relates to the working of technical objects, includes all necessary information connected with the technical condition. The biggest difficulty is the transformation of registered vibroacoustic signals and creation on their basic measures, which will be non-sensitive to any type of interference occurring during the operation of objects and recording signals. To the group of technical objects, for which are already conducted numerous studies all over the world, connected with use of vibroacoustic phenomena for diagnostic purposes which relates to the automotive drive systems, including combustion engines. Combustion engines during its working generate a whole range of vibroacoustic phenomena bringing information on the proper operation of the engine, as well as on condition of each of its elements. In a combustion engine, there are many sources of vibroacoustic phenomena, which contributes to the disruption of diagnostic information. The development of appropriate methods for vibroacoustic signal processing and complete diagnostic systems may allow future extension of the on-board diagnostics OBD system – currently in used cars. The most interesting would be the development of complex system for diagnosing the condition of the individual elements of the car engine operating by basing on information from vibroacoustic signals. In this article are shown results of research, which aim is to diagnose damages of mechanical elements of car combustion engine using vibration signals and artificial neural networks

THE USE OF A MAGNETIC FIELD IN THE ASSESSMENT OF THE OPERATING LOADS OF PNEUMATIC TIRES

Steel is a typical construction material with ferromagnetic properties. This material is often used as a structural component of composites whose task is to transfer mechanical loads. This function is performed by the steel wires placed inside the tires. The aim of the preliminary tests was to determine the influence of air pressure changes in the pneumatic wheel on the distribution of the magnetic field observed outside the tire. The research used a magnetostrictive sensor that reacts to changes in magnetic induction. A sensor with three perpendicular measurement directions was used, and the components of the magnetic induction vector were measured at selected measurement points located in the space surrounding the tested tire. During the tests, measurements were made of the tire’s magnetic field under various load conditions. The results confirmed the occurrence of measurable effects of changes in the magnetic field distribution of the tire depending on the pressure inside

Determination of the effect of tire stiffness on wheel accelerations by the forced vibration test method

The paper presents results of a vibroacoustic signal analysis of the unsprung mass in a car actuated by harmonic kinematic vibrations. A passenger car with a hydropneumatic suspension system and standard tires was examined. Different tire pressures were used during the experiments. The authors applied the short time Fourier transform method with superposition of the Hanning windows combined with the zero complement method. With reference to the STFT spectrum, values of the unsprung mass resonance frequency were identified. The results of the experiments described in the publication are particularly useful for the personnel of vehicle service stations, especially that they relate to the effect of tire pressure changes occurring in a vehicle with a hydropneumatic suspension system on the vibration test results

Application of time shift for nonlinear damping characteristic identification

The symptom of stiffness or damping element wear is change of their characteristic. In paper presented new identification method of dynamic parameters flexible elements of suspension. The determining of damping characteristic was carried out during routine operation. Developed procedure can be used both in internal and external systems of diagnostic