Trans Motauto World
Vol. 10 (2025), Issue 3

Table of Contents

  • TRANSPORT TECHNICS. INVESTIGATION OF ELEMENTS. RELIABILITY

    • Designing and modeling of fixtures for manufacturing grapple buckets Nikolay Stankov

      pg(s) 78-84

      The paper presents the process of automated designing and parametric modeling of fixtures for manufacturing grapple buckets using the CAD system. The presented grapple buckets are designed for bulk materials and they are part of the grapple construction. Grapples are installed on cranes, excavators and other specialized machines. A methodology has been developed that covers all stages of design – from the creation of 3D models of the parts, sub-assemblies and assemblies, to the generation of design documentation through template files. The presented approach allows the development of parametric models with multiple configurations, which cover different variants of the products. Using the presented methodology leads to a reduction in the volume of generated documentation and optimizes the design process. Data management within a PDM system ensures centralized storage, actuality and accessibility of information.

    • Comparative analysis of the braking behaviour of a single track vehicle with different types of front suspensions

      pg(s) 85-88

      Modal simulations comparing the behaviour of different types of motorcycle suspension in specific conditions are found in the literature. However, there is a lack of sufficient field experiments that can be used both to calibrate the models and to realistically assess the advantages and disadvantages of alternative designs. The aim of this publication is to evaluate the behavior of the authors’ alternative front suspension of a motorcycle in braking mode. To achieve this goal, a series of road tests were conducted on the same motorcycle equipped with a different type of front suspension. Both experiments were conducted with the same equipment using the same methodology. The results were processed in the Matlab environment. The obtained results can be used both to evaluate the designed suspension and to validate simulation models and optimize the suspension according to the same methodology. The results were processed in the Matlab environment. The obtained results can be used to validate simulation models and optimize the suspension

    • Renovation of functional surfaces on aluminum alloy injection molds using plasma transfer arc technology (PTA)

      pg(s) 89-94

      Article presents the results of research aimed at determining the quality of the weld layers produced during the renovation of the surfaces of molds intended for injection molding of aluminum alloys. Plasma arc transfer (PTA) technology was used. Medium alloy steel X38CrMoV5-1 (H11) was used as the mold material. Three types of additives in powder form were used to create functional layers: two iron-based types with the designation HSS 23 and HSS 30 and one nickel-based type with the designation DEW Nibasit 625-P. The quality of the layers was assessed using non-destructive and destructive tests. The surface integrity of the layers was assessed using visual and capillary tests. Chemical composition of the elements was determined by energy-dispersive X-ray spectroscopy (EDX) analysis using a SEM microscope and the hardness of individual layers was evaluated also. Since molds are subject to significant frictional wear during operation, friction coefficients

    • An unmanned aerial vehicle with an extended flight time

      pg(s) 95-97

      The question of application of unmanned aerial vehicles (quadrocopters or multicopters) with electric drive for long-term monitoring operations in territories with operating power system or electrified railroad transportation is considered. The disadvantage of drones of this type is the limited capacity of the on-board battery, which implies the need to recharge it, i.e. to stop the flight and return the aircraft to the base. The authors propose a constructive solution to this problem, which is based on a non-contact (induction) method of charging during the flight of an aircraft due to the energy of the electromagnetic field arising from the flow of electric current in the highvoltage wires of the power system or the contact network of railroads. For this purpose, an additional circular electric winding is installed on board the aircraft, in which an electromotive force (EMF) is induced in the electromagnetic field during flight. This EMF is used to charge the battery of the unmanned aerial vehicle. Also, in the proposed design of the unmanned aerial vehicle, solar panels are provided for recharging the batteries during the flight during daylight hours.

    • Modelling of Spacecraft Operating Conditions During Off-Nominal Situations in Orbit and Analysis of Acoustic Emission Monitoring Parameters for Their Optimisation

      pg(s) 98-101

      The subject of the article is the planning and comprehensive preparation of an experiment for monitoring the condition of a satellite’s structure under vacuum conditions modelled using a space environment simulator. Simulating the space environment is essential for verifying the performance of materials, structural components and equipment prior to their actual launch. Such testing makes it possible to confirm the correctness of material selection, the accuracy of engineering calculations and the validity of technical decisions made during the design phase. The behaviour of materials under vacuum, extreme temperatures, sharp thermal fluctuations, and exposure to cosmic radiation may differ significantly from their performance under standard operating conditions on Earth.

  • TRANSPORT. SAFETY AND ECOLOGY. LOGISTICS AND MANAGEMENT

    • Development of the Republican Road Network of Bulgaria in the Conditions of Membership in the European Union

      pg(s) 102-104

      Analyzing the current state of the road infrastructure in Bulgaria, it should be emphasized that it is the result of the long-term preferential and large-scale industrialization of the national economy. This policy, until the beginning of democratic changes in the country, put the development of the road infrastructure on the back burner, due to the limited resources and the set priority. Investment during the transition years is characterized by irrationality, mainly due to the lack of a justified, detailed developed and provided with financial resources long-term plan in this area. Bulgaria’s accession to the European Union led to a rethinking of the content of the state infrastructure policy, a change of views and the need for rapid integration of the national transport system with the European one. The development of the transport infrastructure plays an important role in strengthening the ties between European countries and in the inclusion of new member states of the European Union. The country’s road infrastructure affects the competitiveness, economic growth and employment of the working population. This report examines and analyzes the changes and modifications that have occurred in the structure, condition and density of Bulgaria’s road infrastructure for the period 2007 – 2024. The main goal is to derive recommendations and guidelines for the future sustainable development of the country’s road network based on the analysis of the development of the road infrastructure during the first eighteen years of Bulgaria’s membership in the European Union.

    • A variant of modified algorithm for processing a packet of reflected ultrawideband pulses

      pg(s) 105-107

      This study synthesizes a variant of a modified algorithm for measuring the time delay of a signal reflected from a small-sized (point) target, using an ultrawideband (UWB) sequence of ultra-short (US) probing pulses. The research is a continuation of a series of publications dedicated to the possibilities of reducing the number of operations during analog-to-digital converter (ADC) discretization of the reflected signal

  • VEHICLE ENGINES. APPLICATION OF FUELS TYPES. EFFICIENCY

    • Development of an Internal Combustion Engine for Shell Eco-marathon Competition Vehicle

      pg(s) 108-111

      In this article, the authors describe the development process of a custom internal combustion engine (ICE) for a vehicle competing in the Shell Eco-marathon. The engine will be designed to replace the Honda GX35 previously used in the vehicle. The new engine has to comply with competition regulations and improve the overall fuel efficiency of the vehicle. An engine test stand was developed for measuring the power and brake-specific fuel consumption (BSFC) of small IC engines which allowed tests to be carried out on the GX35 to collect data for the design. Based on the data obtained from the tests and the information gathered from educational materials, a suitable IC engine will be later developed.

    • Power Sources for Unmanned Aerial Vehicles: A Review

      pg(s) 112-117

      Unmanned Aerial Vehicles (UAVs) are increasingly being deployed across a broad range of applications, including surveillance, logistics, environmental monitoring, and military operations. However, their operational effectiveness remains fundamentally constrained by current energy storage technologies, primarily lithium-ion batteries. These conventional power sources suffer from low specific energy, limited endurance, prolonged charging times, and safety concerns under extreme operating conditions.
      This paper presents a comprehensive review of alternative energy solutions for UAV platforms, focusing on hydrogen fuel cells, solar photovoltaic systems, tethered power configurations, wireless power transfer (WPT) technologies, and hybrid propulsion architectures. Each technology is assessed in terms of energy density, system complexity, operational endurance, and suitability for specific mission profiles.