Modeling of “combined cutter - cone” connection in tricone drill bits

A theoretical analysis of the stiffness of the “cutter-cone” connection was performed. In the article the character and magnitude of the tension at the contact of "cutter-cone" are investigated. An analysis of the surface of the openings for carbide inserts revealed traces of plastic deformation and fretting wear.

Method for structural optimization of avionics of unmanned aerial vehicle

This paper presents an approach for identifying the optimal configuration of avionic systems of the unmanned aerial vehicle (UAV) based on an additive multi-attribute utility function.  The function arguments are technical and economic indicators of avionics design quality that are specified in accordance with the UAV requirements.  The method is developed on an improved decision model that has a high degree of adequacy primarily by the increasing number of the utility attributes and using advanced reliability models of avionic systems.  These reliability models consider in addition to the

Using model-oriented decision-making support system for the improvement of safe operation of a ship electric power installation

A model-based decision support system is proposed to increase the reliability of the ship electric power installation. This system consists of a simulation unit and an evaluation unit for modeling results using a fuzzy inference system. The developed system can be implemented as a part of control systems, either on the basis of programmable logic controllers, or on the basis of a separate programmable logic controller. The criteria used to evaluate the results of modeling and possible consequences are considered.

Improved calculation and strength of thermowells during operation

Accurate evaluation of possible safe operation of thermowells essentially depends on the accuracy of the maximum stresses in them during operation. These stresses are generally determined from simple engineering formulas for bulk of canonical shape, mostly cylindrical shells or beams for the relevant boundary conditions. Thus the general solution is obtained step by step. First the tangential stresses are obtained from relations for cylinder subjected to external pressure.

Reliability Model of Fault-tolerant System Based on the Majority Structure {3 of 5} With Combined Structural Redundancy and Maintenance

Designing of radio-electronic systems of responsible purpose with hardware-software implementation involves the mandatory provision of their property of fault-tolerance. The property of fault-tolerance are provided by the use of fault-tolerant systems. For these fault- tolerant systems at the stage of system engineering design it is necessary to solve the problem of reliability structural-parametric synthesis. A designer must have a high degree of adequacy of reliability models of fault-tolerant systems with different configurations to solve such a task.

Responsibility for environmental, including st.246 – illegal cutting of forests

Destruction of forests in Ukraine is one of the current challenges that concern not only environmental, but also ordinary citizens. Uncontrolled deforestation, especially in winter, reaches a critical level. Every day, thousands of illegally felled trees. Experts note that the most objective of reducing the area of the Ukrainian forests and felling oldest arrays show pictures from space.


Today there are many scientific and technical knowledge that make construction a reliable, fast and economical. To provides a safe and durable (the fundamental components of reliability) of builnings and structures are developed the methods of reliability theory. Improving the methods of calculation is enables researchers and designers to create effective structures with a preset (expedient) level of reliability, which directly affects to an amount of required materials and, appropriately, a cost of future building objects in general.

Software Failure Intensity Modelling and Identification the Margins of the Complexity Index

The behaviour of failure intensity function for software reliability model with complexity index depending on the model parameters has been simulated. It allows identifying the margins of the complexity index and explaining the defect revealing function behaviour depending on software complexity.

Extending the features of software for reliability analysis of fault-tolerant systems

The developed software ASNA-2, which is an improved version of the software ASNA-1, is based on the technology of automated estimation of reliability indexes of fault-tolerant systems. This software is designed for automated evaluation of the reliability indexes of fault-tolerant hardware – software systems. This paper describes a software ASNA-2 with the peculiarities of procedures of  reliability analysis of fault-tolerant systems.

Analytical reliability model of a redundant repairable system with limited number of restorations

Modern complex mission-critical systems are built as fault-tolerant systems, i.e. having the ability to function while some of their separate elements have a fault. The complexity of such fault-tolerant systems makes their reliability models quite big and complex. Therefore, such requirements for building models, as the high level of credibility and the appropriate level of formalization, are imposed on these models, which allows to implement the automation to their creating and analysis of reliability and, therefore, using modern computer tools.