Hydraulic Vehicle Damper Controlled by Piezoelectric Valve.

In this paper, an original construction of a vehicle vibration damper controlled by means of a valve based on piezoelectric actuator is presented and investigated. The presented valve allows us to control dissipation characteristics of the damper faster than in other solutions adjusting the size of the gap through which the oil flows between the chambers of the damper. The article also presents the results of the experimental investigation of the above-mentioned damper showing the possibility of changing the value of the damping force five times in about 10 ms by changing the voltage supplying the piezoelectric actuator. Based on these results, dissipative characteristics were determined which enabled the identification of the parameters of the damper numerical model. The article also presents the results of numerical investigations a vehicle model equipped with the developed dampers. The results showed that the developed damper controlled by the use of the piezoelectric actuator can significantly affect vehicle traffic safety by reducing the variation of vertical forces acting on the wheels. The results obtained are so promising that the authors undertook preparations to conduct road tests of a vehicle equipped with the developed dampers.

Studies on Wear of a Milling Chuck for a Production Line of Specialized Elements Used in Lockstitch Machines.

The study aims to determine the wear intensity of selected milling chuck assembly surfaces covered with a protective DLC (Diamond Like Carbon) coating, used on the production line for elements of selected lockstitch machines, and to analyze the stress distributions in the object fixed with such a chuck for the characteristic load systems of this object during its processing. A model of the workpiece was developed using the finite element method. The boundary conditions, including the load and the method of clamping the workpiece, resulted from the parameters of the milling process and the geometric configuration of the milling chuck. Stress distributions in the workpiece for specific milling parameters and for various configurations of the milling chuck holding the workpiece are included in the article. The model experimental studies of wear were conducted in the contact zone between two surfaces covered with DLC: one on the element of the milling chuck pressing the workpiece and the other on the eccentric cams of this holder. The obtained wear values and shapes for the worn surfaces are also shown. The wear intensities for the steel plunger fins modelling swivel arm of the holder were by an order higher than those of corresponding steel shaft shoulders modelling eccentric cam of the holder. The linear wear intensities for these mating components may be expressed in terms of a function of average contact pressure and sliding speed in a corresponding contact zone. The indentation of eccentric cam into mating surface of the swivel arm of the holder increased nonlinearly with the enhancement of number of cycles of the eccentric cam.

Determining vehicle pre-crash speed in frontal barrier crashes using artificial neural network for intermediate car class.

This paper introduces a new, innovative approach to pre-crash velocity determination, namely the artificial neural networks. A perceptron based on a database obtained from NHTSA (National Highway Traffic Safety Administration) with numerous data concerning frontal vehicle crash tests: i.e. vehicle mass, deformation zone and deformation coefficients C1-C6. Part of the database entries were used to train the network to develop consistent accuracy and the remainder was used as validation and training sets.

Work of non-elastic deformation against the deformation ratio of the Subcompact Car Class using the variable correlation method.

The presented study considers a Subcompact Car Class in a new non-linear method utilising the work W of car deformation defined as an algebraic function of deformation ratio Cs. In order to develop the experimental data, the method of variable correlation is utilised. Data from the NHTSA (National Highway Traffic Safety Administration) database comprising numerous frontal crash tests are used for the determination of mathematical model parameters. In the non-linear method used up until now, the so-called energetic approach, collisions are treated as non-elastic. The velocity threshold that defines the elastic collision was set to be 11km/h. Such an approach, which is very simplified, determines the linear dependence of energy lost during deformation on deformation coefficient Cs. This coefficient is calculated as a mean value, taking into account the weights of deformation points C1-C6. In this paper, the authors propose a more precise non-linear method in order to determine the work of deformation, and have used the more complex form of deformation coefficient.

Non-linear method of determining vehicle pre-crash speed based on tensor B-spline products with probabilistic weights - Intermediate Car Class.

In the following study we consider the Intermediate Car Class. We apply a novel non-linear method, where the work W of car deformation is defined as an algebraic function of deformation ratio Cs. We use the data from the NHTSA (National Highway Traffic Safety Administration) database comprising numerous frontal crash tests. On the basis of this database, we determine the mathematical model parameters. In the so-called energetic approach, collisions are treated as non-elastic. The velocity threshold that defines the elastic collision was set to be 11km/h. Such an approach, which greatly simplifies our considerations, determines the linear dependence of energy lost during deformation on deformation coefficient Cs. The coefficient Cs is calculated as a weighted mean value of deformation points C1-C6. In this paper, the authors suggest a more precise non-linear method in order to determine the work of deformation.

Nonlinear approximation method of vehicle velocity Vt and statistical population of experimental cases.

In car crash analysis three calculations methods can be distinguished: analytical (Campbell, McHenry, Strother, Prasad, Crash3 etc.), comparative and graphical (Lindquist et al., 2003; Prasad, 1990; Sharma et al., 2007; Wach and Unarski, 2006; Zuchowski, 2015) [15,23,25,29,33]. The number and reliability of these methods, in reference to modern vehicles and their structure, may lead to unclear conclusions. This issue proves to be significant, especially due to slight modifications of both input parameters and input data for the analysis of the method. This may give substantially different answers to the questions asked in court. After a thorough analysis of this problem, a new analytical method was devised, based on a new input database - NHTSA, which shows great improvement in the accuracy of obtained results. The aim of this paper is to prove that the nonlinear method is a very effective tool for processing experimental data in a large enough number of cases.