scholarly journals On the Possibility of Generalizing the Results of Studies of Dynamical Systems on the Example of a Vehicle Suspension

Machines ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 68
Author(s):  
Anatoliy Dubrovskiy ◽  
Sergei Aliukov ◽  
Konstantin Osintsev
Keyword(s):  
Differential Equations ◽  
Dynamic Properties ◽  
Single Point ◽  
Vehicle Suspension ◽  
Engineering Structures ◽  
Entire Family ◽  
The Road ◽  
Specific Parameter ◽  
Specific Object ◽  
Parameter Values

The dynamics of mechanical systems, the operation of electromagnetic and electronic devices and devices, the principle of operation of a number of machines and mechanisms, engineering structures from various fields are often described by differential equations and their systems. Differential equations are often mathematical models of the movement and operation of various engineering objects. As a rule, such equations are solved by numerical methods for specific parameter values. These methods of solving differential equations are widely used in practice. However, these methods also have significant disadvantages. For example, the solution of differential equations is obtained for a specific object with the specified parameters. In this case, a solution is obtained for a single point in the parameter space of a set of similar objects, points in this space of the considered family of objects. A natural question arises: Is it possible to extend the results of the solution for a single point in space (a specific object) and the identified properties and regularities to other points (other objects) of the considered family? The purpose of this article is to identify conditions under which it is possible to generalize the results of solving differential equations with specific parameter values describing a single construction to the entire family of similar constructions, the entire space of parameters under consideration. The implementation of the identified conditions is illustrated by the example of solving the problem of “analyzing the dynamic properties of a mathematical model of a car with adaptive (adjustable) suspension of a new principle of action (developed by the authors), moving at a variable speed along an indirect profile of the road surface and developing recommendations for their radical improvement”.

Optimal Wavelet Parameters for System Identification of Civil Engineering Structures

2018 ◽  
Vol 34 (1) ◽  
pp. 197-216 ◽  
Author(s):  
Carlos A. Gaviria ◽  
Luis A. Montejo
Keyword(s):  
Numerical Study ◽  
Optimal Parameter ◽  
Dynamic Properties ◽  
Damping Ratio ◽  
Computational Cost ◽  
Gabor Wavelet ◽  
Engineering Structures ◽  
Time Frequency ◽  
Complex Morlet Wavelet ◽  
Parameter Values

Damage-induced changes in structure dynamic properties are commonly tracked with time-frequency representations (TFRs). One of the most widely accepted tools for determining a TFR is the continuous wavelet transform (CWT). The success of CWT analysis is highly dependent on selecting the most appropriate values for the parameters that define the mother wavelet. This article presents a detailed analytical and numerical study to select optimal wavelet parameters using the complex Morlet wavelet (CMOR) and the Gabor wavelet. The results obtained suggest that it is possible to define optimal parameter values based on identification target, instantaneous frequency, or average damping ratio. This reduces the computational cost of a reliable CWT analysis when compared with currently employed iterative methodologies based on minimal Shannon entropy criteria.

scholarly journals An Oscillation Criterion of Nonlinear Differential Equations with Advanced Term

Symmetry ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 843
Author(s):  
Omar Bazighifan ◽  
Alanoud Almutairi ◽  
Barakah Almarri ◽  
Marin Marin
Keyword(s):  
Differential Equations ◽  
Fourth Order ◽  
Nonlinear Differential Equations ◽  
Oscillation Criterion ◽  
Riccati Technique ◽  
Oscillation Criteria ◽  
Specific Parameter ◽  
Parameter Values

The aim of the present paper is to provide oscillation conditions for fourth-order damped differential equations with advanced term. By using the Riccati technique, some new oscillation criteria, which ensure that every solution oscillates, are established. In fact, the obtained results extend, unify and correlate many of the existing results in the literature. Furthermore, two examples with specific parameter values are provided to confirm our results.

scholarly journals KARAKTERISTIK CAMPURAN AC-WC MENGGUNAKAN MATERIAL RECLAIMED ASPHALT PAVEMENT DENGAN TAMBAHAN ASPAL PEN. 60/70 YANG DISUBSTITUSI STYROFOAM

2019 ◽  
Vol 2 (2) ◽  
pp. 149-157
Author(s):  
Hendra Arianto ◽  
Sofyan M. Saleh ◽  
Renni Anggraini
Keyword(s):  
Asphalt Pavement ◽  
Asphalt Mixture ◽  
Reclaimed Asphalt Pavement ◽  
Additional Material ◽  
Reclaimed Asphalt ◽  
The Road ◽  
Concrete Type ◽  
Technical Specifications ◽  
Parameter Values

Reuse of reclaimed asphalt pavement material (RAP) is an alternative which applicated for potential enough on the roughness of the road. RAP material can be reused by adding the asphalt and the new aggregate according of the mixture composition so that it is expected will be obtained the quality as planned. One of the efforts made in improving the quality of asphalt mixture RAP material is using a modified asphalt with additional material, such as styrofoam. The use of styrofoam into the asphalt is expected to improve the technical properties of a mixture. The purpose of this research is to know the comparative characteristics of hot mix asphalt (asphalt concrete) type AC-WC that uses RAP material with additional asphalt pen. 60/70 and asphalt pen. 60/70 substitution in the styrofoam by 8%, 10% and 12% against the weight of asphalt based on levels of asphalt left on the material. The initial stages of this study is to conduct an examination of the physical properties of RAP material, then manufacturing a specimen with variations of the addition of asphalt and aggregate new levels based on the job mix diesign (JMD) Bina Marga Aceh (2013). Based on research results, parameter values marshall on all types of asphalt mixture with new aggregate as well as RAP materials and the use of 100% asphalt pen. 60/70 additional or different types of asphalt on OAC has fulfilled the technical specifications defined by the Bina Marga (2014). Best stability values obtained on asphalt mixture using RAP material with additional asphalt pen. 60/70 with 12% styrofoam substitution on OAC JMD Bina Marga Aceh, that amounted to 3,308.72 kg, the lowest value stability retrieved on asphalt mixture using a new aggregate based on the results of Department of Bina Marga Aceh on OAC i.e. of 983.94 kg.

scholarly journals Higher Order Haar Wavelet Method for Solving Differential Equations

2020 ◽  
Author(s):  
Jüri Majak ◽  
Mart Ratas ◽  
Kristo Karjust ◽  
Boris Shvartsman
Keyword(s):  
Differential Equations ◽  
Computational Cost ◽  
Haar Wavelet ◽  
Higher Order ◽  
Wavelet Method ◽  
Haar Wavelet Method ◽  
Convergence Results ◽  
Key Characteristics ◽  
Parameter Values ◽  
Excellent Accuracy

The study is focused on the development, adaption and evaluation of the higher order Haar wavelet method (HOHWM) for solving differential equations. Accuracy and computational complexity are two measurable key characteristics of any numerical method. The HOHWM introduced recently by authors as an improvement of the widely used Haar wavelet method (HWM) has shown excellent accuracy and convergence results in the case of all model problems studied. The practical value of the proposed HOHWM approach is that it allows reduction of the computational cost by several magnitudes as compared to HWM, depending on the mesh and the method parameter values used.

VIBRATION OF CIRCULAR BLADED DISK WITH IMPERFECTIONS

2011 ◽  
Vol 21 (10) ◽  
pp. 2893-2904 ◽  
Author(s):  
LADISLAV PŮST ◽  
LUDĚK PEŠEK
Keyword(s):  
Dynamic Properties ◽  
Single Point ◽  
Three Dimensional ◽  
Rotating Disk ◽  
Fe Model ◽  
Rotating Disks ◽  
Response Curves ◽  
State Response ◽  
Bladed Disk ◽  
Linear Damping

The steady state response of a model of circular bladed disk with imperfection is investigated. Disk imperfection results from additional two groups of damping heads fixed on opposite ends of one diameter. These damping heads are introduced into the computing model as additional point mass, damping and stiffness. Such type of imperfection causes the bifurcation of double eigenfrequencies into pairs of close eigenfrequencies. The effect of imperfection is examined both numerically on three-dimensional nonrotating FE-model and analytically on a simplified split 2DOF model of rotating disk excited by single point harmonic force. Nonlinear friction connection is analyzed and equivalent linear damping coefficient is derived and used in the calculation procedure. It is shown that nonproportional distribution of damping strongly influences the high of resonance peaks. Some examples of response curves illustrate the dynamic properties of stationary and rotating disks with mass-damping-stiffness imperfection.

Aspects of Osillations of Beams and Plates

2005 ◽  
Author(s):  
Mariya A. Zarubinska ◽  
W. T. van Horssen
Keyword(s):  
Boundary Value ◽  
Initial Boundary ◽  
Initial Boundary Value Problem ◽  
Initial Boundary Value Problems ◽  
Boundary Values ◽  
Internal Resonances ◽  
Specific Parameter ◽  
Plate Equations ◽  
Initial Boundary Value ◽  
Parameter Values

In this paper some initial boundary value problems for beam and plate equations will be studied. These initial boundary values problems can be regarded as simple models describing free oscillations of plates on elastic foundations or describing coupled torsional and vertical oscillations of a beam. An approximation for the solution of the initial-boundary value problem will be constructed by using a two-timescales perturbation method. For the plate on an elastic foundation it turns out that complicated internal resonances can occur for specific parameter values.

scholarly journals Modelling Properties of an Alkaline Electrolyser

Energies ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 3073
Author(s):  
Krzysztof Górecki ◽  
Małgorzata Górecka ◽  
Paweł Górecki
Keyword(s):  
Potassium Hydroxide ◽  
Dynamic Properties ◽  
Operating Conditions ◽  
High Productivity ◽  
Electrolysis Process ◽  
Average Value ◽  
Current Voltage ◽  
Wide Range ◽  
Current Voltage Characteristics ◽  
Parameter Values

This paper proposes a model of an electrolyser in the form of a subcircuit dedicated for SPICE. It takes into account both the electric static and dynamic properties of the considered device and is devoted to the optimisation of the parameters of the signal feeding this electrolyser, making it possible to obtain a high productivity and efficiency of the electrolysis process. Parameter values the describing current-voltage characteristics of the electrolyser take into account the influence of the concentration of the potassium hydroxide (KOH) solution. A detailed description of the structure and all the components of this model is included in the paper. The correctness of the elaborated model is verified experimentally in a wide range of changes in the value of the feeding current and concentration of the KOH solution. Some computations illustrating the influence of the amplitude, average value, duty factor, and frequency of feeding current on the productivity and efficiency of the electrolysis process are performed. On the basis of the obtained results of the investigations, some recommendations for the operating conditions of electrolysers are formulated.

scholarly journals Mobile Laser Scanning Data for the Evaluation of Pavement Surface Distress

2020 ◽  
Vol 12 (6) ◽  
pp. 942 ◽  
Author(s):  
Maria Rosaria De Blasiis ◽  
Alessandro Di Benedetto ◽  
Margherita Fiani
Keyword(s):  
Point Cloud ◽  
Laser Scanning ◽  
Road Traffic ◽  
Single Point ◽  
Three Dimensional ◽  
Point Clouds ◽  
Road Surface ◽  
Important Indicator ◽  
The Road ◽  
Laser Systems

The surface conditions of road pavements, including the occurrence and severity of distresses present on the surface, are an important indicator of pavement performance. Periodic monitoring and condition assessment is an essential requirement for the safety of vehicles moving on that road and the wellbeing of people. The traditional characterization of the different types of distress often involves complex activities, sometimes inefficient and risky, as they interfere with road traffic. The mobile laser systems (MLS) are now widely used to acquire detailed information about the road surface in terms of a three-dimensional point cloud. Despite its increasing use, there are still no standards for the acquisition and processing of the data collected. The aim of our work was to develop a procedure for processing the data acquired by MLS, in order to identify the localized degradations that mostly affect safety. We have studied the data flow and implemented several processing algorithms to identify and quantify a few types of distresses, namely potholes and swells/shoves, starting from very dense point clouds. We have implemented data processing in four steps: (i) editing of the point cloud to extract only the points belonging to the road surface, (ii) determination of the road roughness as deviation in height of every single point of the cloud with respect to the modeled road surface, (iii) segmentation of the distress (iv) computation of the main geometric parameters of the distress in order to classify it by severity levels. The results obtained by the proposed methodology are promising. The procedures implemented have made it possible to correctly segmented and identify the types of distress to be analyzed, in accordance with the on-site inspections. The tests carried out have shown that the choice of the values of some parameters to give as input to the software is not trivial: the choice of some of them is based on considerations related to the nature of the data, for others, it derives from the distress to be segmented. Due to the different possible configurations of the various distresses it is better to choose these parameters according to the boundary conditions and not to impose default values. The test involved a 100-m long urban road segment, the surface of which was measured with an MLS installed on a vehicle that traveled the road at 10 km/h.

CROSSINGS FOR ANIMALS – AN EFFECTIVE METHOD OF WILD FAUNA CONSERVATION GYVŪNŲ PERĖJOS – EFEKTYVUS FAUNOS APSAUGOS METODAS / ПЕРЕХОД ДЛЯ ЖИВОТНЫХ – ЭФФЕКТИВНЫЙ МЕТОД ОХРАНЫ ФАУНЫ

2012 ◽  
Vol 20 (1) ◽  
pp. 86-96 ◽  
Author(s):  
Damian Beben
Keyword(s):  
Natura 2000 ◽  
Steel Bridge ◽  
The European Union ◽  
Engineering Structures ◽  
The Road ◽  
Wild Fauna ◽  
Bridge Structures ◽  
Road Systems ◽  
On The Road ◽  
Corrugated Plates

The paper characterizes the problem of preservation of wildlife animals in connection with extension of transportation road systems. The constantly evolving transportation infrastructure in Europe, especially in its Midwestern part, on one hand connects, making it easier for people to travel and ship goods, but on the other hand it irreversibly divides and leaves a painful impress on virgin natural areas (fragmentation of the environment). The paper briefly presents the European Ecological Network Nature 2000 as the European Union program concerning the environmental protection. It enumerates possible types of animal crossings together with their characteristics. Some examples of underpasses, overpasses and crossings on the road surface are also presented. It also presents specificity and phases of designing engineering structures of this type, as well as the most common design errors and their influence over the use of such structures by animals. Finally the soil-steel bridge structures made from corrugated plates are characterized in their function as crossings for animals. The conclusion mentions complexity of the problem of animal crossing construction, which can be of use to designers and constructors of this type of engineering structures. Santrauka Straipsnyje apžvelgtos laukinės gyvūnijos išsaugojimo problemos, susijusios su besiplečiančiu transporto tinklu. Nuolat besivystanti transporto infrastruktūra Europoje, ypač Vidurio vakaruose, viena vertus, jungia ir palengvina žmonių mobilumą,sukuria jungtį su uostais, tačiau, kita vertus, daro didelę žalą natūraliai aplinkai (aplinkos fragmentacija). Straipsnyje trumpai pristatoma Europos ekologinio tinklo ,,Natura 2000“ ES programa, skirta aplinkos apsaugai. Išvardyti galimi gyvūnų perėjų tipai su jiems būdingomis charakteristikomis. Pateikiami požeminių, virš kelio ir perėjų per patį kelią pavyzdžiai. Straipsnyje taip pat apžvelgiama inžinerinių struktūrų projektavimo specifika ir fazės, aptariamos dažniausiai pasitaikančios projektavimo klaidos ir jų įtaka gyvūnams. Galiausiai apibūdinamas dirvos ir plieninių tiltų struktūros, pagamintos iš gofruotų plokštelių, naudojimas gyvūnų perėjoms. Išvadose aptariamas gyvūnų perėjų konstrukcijų problemų kompleksiškumas, į kurį turėtų atkreipti dėmesį gyvūnų perėjas konstruojantys inžinieriai ir dizaineriai. Резюме Анализируются проблемы охраны диких животных в связи с расширяющейся транспортной сетью. Постоянно развивающаяся транспортная инфраструктура в Европе, особенно на западе центральной части Европы, с одной стороны, объединяет людей, облегчает их мобильность, открывает доступ к портам, с другой – наносит непоправимый вред натуральной природе. В статье вкратце представлена программа Европейской экологической сети – Natura 2000, касающаяся охраны окружающей среды. Перечислены возможные типы переходов для животных с их типичными характеристиками. Представлены примеры подземных переходов, переходов над дорогой и по самой дороге. Проанализирована специфика и фазы проектирования инженерных структур, а также часто совершаемых ошибок при проектировании и их влияние на животных. Охарактеризовано применение для переходов животных почвенностальных структур мостов из гофрированных пластин. Проанализирована комплексность проблем, касающихся конструкций для переходов животных, на которые следует обратить внимание инженерам и дизайнерам при констру ировании переходов для животных.

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