Experimental assessment of eigenfrequencies and stiffness of the elastically supported body

The aim of the research is to derive an analytical solution describing the vibrations of railway wagons caused by asymmetrical loading of cargo for prediction of dangerous conditions. A presumption for the dynamic analysis and assessment of the driving quality of railway vehicles is an important experimental determination and verification of the basic characteristics of the suspension respectively. A method for determining these characteristics for two-axle vehicles has been developed and applied. This method requires knowledge of the position of the center of gravity and the main central moments of inertia. Vehicle bodies, chassis frames, and wheelsets are assumed to be rigid bodies under the investigation of these characteristics. The characteristics of the springs are linear or can be linearized. The vehicle body performs a general spatial movement. The result of the investigation is an analytical method to obtain the required characteristics needed for the dynamic analysis of the vehicle.

Assessment of Selected Properties of Varnish Coating of Motor Vehicles

The technology and methods of testing the properties of varnish coatings used in motor vehicles are constantly and successfully developed. However, in the case of automotive varnish renovation coatings used in the repair of car bodies, the problem of fitting the quality of these coatings to the quality and current condition of the coating applied to undamaged vehicle components is not definitely solved. The main goal of the research was to determine the thickness and gloss distribution of the varnish coatings. The thickness and gloss of the varnish coating on the entire body of the vehicle were measured. Classical methods of assessing these properties were used. Defects in the renovation coating were also simulated, to show their negative impact on the varnish quality. The performed tests allowed for development of a procedure and algorithm for evaluation of the quality of the car’s renovation coating after the repair of the car body. The proposed procedure, expressed with the presented algorithm, allows to fit the obtained renovation coating to the quality and condition of the coating manufactured in factory on the car body in the range of its thickness up to 270 µm and gloss in the range of 5–90 GU. The developed procedure for the assessment of renovation coatings can be used in workshops that repair vehicle bodies. This will allow to improve the quality of renovation coatings and bring their properties, such as thickness or gloss, closer to those applied to the vehicle’s body at the factory.

Prediction of Driver’s Center of Gravity Position on a Stand-Up Type PMV Considering Intentions

In recent years, Personal Mobility Vehicles (PMVs) have been attracting attention as a new means of transportation. They are environmentally friendly without exhausting harmful gases. These vehicle bodies are relatively smaller than cars, so they have a high affinity for pedestrian space. However, depending on the specifications of the vehicle, driver’s behaviors have great effect on the vehicle movement because the weight of the vehicle is comparatively low. In addition, applying the automatic driving on PMV will be one of the next steps to make use of PMVs. It is important to understand the dynamic behavior of drivers not only during their intentional driving but also during the automatic driving. In this study, we focused on stand-up type PMVs. We measured driver’s center of gravity and several forces on a standing PMV. From the measurements, we looked at the correlation coefficient, and used multiple regression analysis to derive the prediction equations of driver’s center of gravity position on stand-up type PMVs. These results can be applied to simulate the dynamic motion of the PMV and a driver.

Material Selection Considerations for Lightweight Automotive Bodies

Lightweight is a trend of new vehicle development, driven by government regulations, environmental concerns, and customer needs. A major effort in the automotive industry is on light weighting vehicle bodies. This chapter reviews the various materials, their characteristics, weight reduction potentials, and costs for light weighting vehicle bodies. The chapter also exams the joining technologies on their principles, applications for the lightweight materials, and influencing factors for choosing a joining process. Furthermore, this chapter discusses the development trends of material selection and joining technology applications.

Differentiating the stiffness of the side of the car

Expertise on the materials of road accidents (road accidents), calculate the speed of the vehicles involved in the accident by analyzing the resulting deformation damage by the average stiffness coefficients of the vehicle bodies. But this entails the presence of an error in the calculation and, as a result, not a correct result due to the fact that the internal structure of the side of the car is heterogeneous – the stiffness in each of its areas is different. To eliminate possible errors when using the averaged coefficients, the article offers a method for calculating the stiffness coefficients for various areas of the side of cars that have received deformations as a result of an accident.

Model of the Secondary Path between the Input Voltage and the Output Force of an Active Engine Mount on the Engine Side

The active engine mount (AEM) provides an effective solution to improve the acoustic and vibration comfort of a car. The same AEM can be installed for different engines and different vehicle bodies and attenuates the engine vibration, which is one of the most pressing challenges. To study this problem, this paper develops a mathematical model of a secondary path between the input voltage and output force of the AEM on the engine side considering the frequency-dependent characteristic of the stiffness, which includes the structure parameters of the AEM as well as the dynamics of the actuator, the fluid in the inertia track, the foundation (vehicle body), and the attenuated vibrating object (AEM preload or engine). The proposed model is validated by three test cases without vibration excitation, which are performed with different AEM preloads and foundations. The AEM is considered as an active part and passive part, the mass of which is determined experimentally. Parameter effect on the dynamic characteristics of the secondary path of the AEM is studied based on three tests and a numerical simulation.