Work describes an approach to complex thermal analysis of buses salons starting from engine heat radiation and with its further distribution along the internal bus volume. Provided workflow chain in the article could be used as the base for any bus type climate and thermal investigation with the next optimization events. Heat analysis with materials thermal conductivity parameters was proceeded using Ansys Fluent and Ansys Steady State Thermal addons. Based on the obtained results, it is possible to draw conclusions about the impact of different parameters (temperature, heat radiation, humidity, etc) on the buses salons microclimate. Presented work could be much actual in practical plane like methodology used for efficient bus bodies development by engineers who could apply suggested materials for calculating the distribution of heat from the engine in the passenger compartment of the bus and studying the microclimate in different operating conditions. That could be especially valuable at the stage of the new bus models design and modelling.

This work is a logical continuation of studies presented in the author’s previous publications [1,2,3] on establishing the analytical application features of the developed methodology for simulating natural tests in accordance with UN/ECE Regulation No. 66. [4], as well as evaluating the identity between calculated and experimental results of checking the reserve of cabin space. The relevance of the proposed methodology is primarily related to the need to comply with the requirements of the current Regulation regarding the level of passive safety of passengers in the cabin during the certification of buses: a real-life approach to testing is conducted with a series of crash tests, which lead to the inevitable destruction of the bus body frame. We would like to remind that the specific weight of the body cost in the total cost of the bus, depending on its type, can reach up to 50% of its price, which leads to exorbitant costs during the certification of road prototypes before the start of their commercial operation.

Energy consumption and thermal comfort are among the issues that research engineers of heating, ventilation and air conditioning systems deal with when investigating the most feasible solutions for their implementation. Existing methods of thermal comfort assessment are not optimized in two important and interrelated aspects: achieving thermal comfort (a) at the lowest possible energy consumption (b). Thermal comfort is situationally achieved when occupants perceive the ambient temperature, humidity, air movement and thermal radiation as ideal and do not prefer warmer or colder air or a different humidity level. Thermal comfort is defined by ASHRAE Standard 55 as a subjective concept characterized by the sum of sensations that create physical and mental well-being in a person. That is, he/she is in a state in which he/she feels comfortable and does not need to change one or more environmental parameters. Many studies have been conducted according to the international standards for thermal comfort in vehicles. The presence of a large number of people in the bus leads to a deterioration of the air quality in its interior. The loss of quality is mainly caused by gases resulting from breathing and other organic particles. The presence of moisture, combustion products, particles can also reduce the air quality in the interior. Air quality is affected by the design features of heating, ventilation and air conditioning systems, which largely depend on the location of the power unit, which is the subject of the research. The influence of the bus engine layout is analysed in the presented work: for the rear-engine layout, the location of the engine vertically in the interior and other cases are also considered. Special fans are installed in the engine compartment to remove heat emitted by the engine.

Recently, the production of metal structural elements using additive processes is gaining popularity. They allow the production of an element of any geometry and structure, while reducing the mass of the produced part. Unfortunately, the AM technology causes structural elements to be burdened with numerous defects in the form of porosity, unmelted powder, weak interlayer bonds or residual stresses, etc. These defects translate into the possibility of an early, uncontrolled fatigue crack. For this reason, it is important to find ways to quickly detect damage caused by random variable loads. The work presents methods of diagnosing cracks and fatigue damage in structural elements produced using 3D printing. The division of research methods allowing for the detection of defects in structural elements and the characteristics of the most popular methods, taking into account their advantages and limitations, were presented. Methods appropriate for a given type of material, test conditions and damages are indicated. The most important methods of diagnosing defects in printed elements include: penetrating, ultrasonic, radiographic, eddy current and thermal imaging methods.

This paper considers the influence of the transitional modes of movement (acceleration, braking) of a multi-link vehicle on the vibration protection of transported non-fixed or partially fixed cargoes. The impact phenomenon, in this case, can be strengthened by the existence of coupling mechanisms between the links of a multi-link vehicle. To reduce such horizontal impact loads, it is advisable to use elements with viscoelastic damping in the coupling devices of a multi-link vehicle. To study the actual impact phenomena during the transportation of non-fixed or partially fixed cargoes under the extreme modes of movement of two-link vehicles, it is proposed to use a flat two- and three-mass dynamic model with viscoelastic damping. At the same time, the theory of elastic impact has been applied while the elastic-damping characteristics of vehicles' suspensions were not taken into consideration. It has been shown that the reported research results make it possible to estimate the approximate values of the mechanical parameters for restrictive devices that protect non-fixed or partially fixed cargoes from impact, during the transition modes of transportation, depending on the conditions of motion. This practically makes it possible to select the rational design parameters for the elements of viscoelastic restrictive devices, in particular elastic elements and dampers, in order to reduce impact loads on non-fixed heavy cargoes during transportation under extreme modes of movement. Based on this study, a procedure of vibration protection of non-fixed or partially fixed cargoes in the body of a two-link vehicle during its uneven movement has been proposed, which implies determining the maximum dynamic loads on these cargoes as well as the possibility of choosing the rational design parameters for restrictive devices in order to prevent or reduce the impact of these cargoes hitting the restrictive devices