International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

The modern society is highly material and financially oriented. Due to this reason, the processes have to be cost-effective with optimizing the expenses. Despite the tendencies of modernization, technological progress and automating proceedings, the role of a person as an “actor” in these processes is irreplaceable. Unfortunately, especially in the countries with highly developed economy, the expenses for staff are really high. The worker’s protection from occupational accidents and professional illnesses, as well as the employees’ efficiency in a long-term plan are connected with consumption resources which for the factories are often quite high. In short-term aspect, the resource-saving in a way of good working conditions is not a decision.

During the last years, more and more attention is given to a factor that remains at the background of a workplace – the stress. There are many studies about its negative effect on the workers, as that reflects on the whole effectiveness of the companies and the factories. The stress-management and the prevention of the Burnout syndrome are important prerequisites for sustainable economic growth because the performance, creativity, productivity, and competitiveness of every factory depend on the qualified, healthy, motivated and organized employees who work there. The aim of the study is a comparative analysis of the working conditions in Bulgaria, Macedonia and Germany for several branches for which personal indicators as environment, habits, motivation, etc. Are observed. Based on assessment of the workplace stress, conclusions should be drawn for its impact as a factor, threatening the workers’ health.

The paper presents a method for calculating the durability of structure regular zones in view of working stresses and aircraft routine flight profile. Application of the method is advisable at the early design stages. The method is based on the discrete atmospheric turbulence model and dependence model for durability calculation by nominal stresses. Fatigue damage for a routine flight has been determined as the amount of damage due to accidental loads and the damage resulting from enveloping ground-air-ground cycle, naturally repeated during each flight. It has been noted that the consideration of the fatigue curve break point in the low-stress area leads to an increase in the calculated durability by 10-15%. A comparison has been made of the calculated durability values for two airplanes with the experimental data of TsAGI. The correlation is satisfactory enough.