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The suspension system of track vehicles is often equipped with torsion bars. The torsion bar is a key element of the vehicle's suspension system. The service life of torsion bars depends primarily on the quality of the material used, the diameter of the torsion bars and the method of attachment and placement. In order to obtain the characteristics of the torsion bar, an experimental test stand was created on which accelerated tests were performed. Furthermore, a virtual model of torsion bar operation was created. The torsion bar was modelled using finite elements (FE part). Dynamic simulation was performed using MSC Adams software. Finally, the values measured in the accelerated tests and the results of simulations were compared. Comparing the values found, it was proved that this difference is not significant. This virtual model can be used to investigate the service life of torsion bars and to predict their service life.

The combat vehicle gearbox, during the operation, generates vibration signals being related to the technical condition of gearbox. The analysis of the vibration signal could be used to determine accurately the behaviour of gearbox. Along with the development of the computer technology, the multi-body dynamic solution has been used widely to simulate, analyse, and determine the technical condition of gearbox. The purpose of this paper is to introduce the dynamic model of combat vehicle gearbox, and the simulation process based on the multi-body dynamic software, namely MSC.ADAMS. This proposed model allows the detection of failure conditions of individual gears and bearings in the gearbox. In this way, the fault conditions of the individual transmission components are identified. In the future, we would like to include a material wear module in the model, and we would like to model the life of the gearbox. We assume that we would also carry out accelerated tests of the gearbox to verify validity.

This paper focuses on creating a virtual model of mechanical gearbox used in medium-sized terrain vehicle using MSC.Adams software. This software is regarded as the most common and effective tool to simulate the gearbox as multibody system and to record and analyse the vibration signal from the gearbox. The paper makes an overview of modelling and simulation and performs an analysis with frequency spectrum. The paper demonstrates that it is possible to simulate vibration signals through the model of the gearbox created in 3D CAD software and then analyse in multi-body dynamics software MSC.Adams. Successful application of the virtual model not only help us decrease the cost of design work, but also help us identify the patterns of the vibration signal and the relations between the signal and the technical condition of the gearbox. The goal is to create a virtual model of a mechanical gearbox. In MSC.Adams, the vibration values of the rotating components can be detected in different gears. These values are then analysed and evaluated. The result is a simulation of fault states and identification of vibration frequencies for practical applications.

The aim of this article is to evaluate the technical condition of a mechanical four-speed gearbox tightly connected to a mechanical two-speed auxiliary gearbox placed in an off-road vehicle. When observing the technical condition of the mechanical gearbox, we used one of technical diagnostics methods, namely vibrodiagnostics. The mechanical gearbox was monitored during all its life cycle up to failure occurrence. In the article there is a detailed description of the stand where the gearbox technical condition was monitored. When observing vibration signals, we used four tri-axial sensors placed in four selected spots depending on the design arrangement of antifriction bearings. In order to evaluate the measured results, two methods were applied, namely the root mean square gRMS based on the measured acceleration in three axes. The other method used for monitoring the technical condition was the Crest factor. The aim of the experiment was to monitor the technical condition of the mechanical gearbox, mainly its antifriction bearings, therefore the values were measured when the gear was put into fourth position and into overdrive in the auxiliary gearbox. When the gear is put into fourth position, the torque is transmitted from the motor through the main gearbox and the auxiliary gearbox directly. Single gearbox wheels are engaged but not loaded (they do not transmit the torque). At the end of our article we introduced the measured values along with the oral evaluation of the technical condition of the mechanical gearbox and the auxiliary gearbox.

The knowledge and experience learnt from product designing have resulted in development of their reliability theory. The classical concept of safe – life is based on product over dimensioned design that considers safety factor or safety margin for measure. However, practical engineering has found this concept in a manner inconvenient as design fault-resistance to determine the ultimate condition and operating stress are random values. A way out is in the concept of stochastic approach to reliability design resulting from the defect-production probability distribution law. That concept allows product designing with predetermined reliability, such as in the example contained in this paper.

The paper proposes a model of tribotechnical diagnostics, which allows us to determine the technical condition of an internal combustion engine within its life cycle and then take measures, including its decommissioning due to excessive wear of major components. The paper also focuses on tribodiagnostic methods that are suitable for assessing the technical condition of internal combustion engines used in various means of transport (automobiles, railway locomotives powered by internal combustion engines, aircraft powered by reciprocating internal combustion engines, special and garden equipment). An internal combustion engine from agricultural equipment was selected for the experiment and monitored throughout its life cycle. The paper describes in detail the appropriate methods used for the proposed tribotechnical diagnostics model, including the results from the measurements by these methods. The said methods were then evaluated and mutually compared. The following advanced instrumental analytical methods were used to evaluate the collected engine oil samples: atomic emission spectrometry (AES), ferrography, automatic laser counter and LNF particle classifier, FTIR infrared spectrometry. The result of the work (paper) is the design of a tribotechnical diagnostics model for determining the technical condition of an internal combustion engine during its life cycle and the determination of limit values for assessing the technical condition of a Honda GCV 165 internal combustion engine. The results are based on individual measurements. [ABSTRACT FROM AUTHOR]

The paper deals with the prediction of life cycle costs related to special motor vehicles. In the first part, there is an analysis of the applied commercial software programs used for calculating and predicting the life cycle cost of vehicles. Next, there is a description of risks which might occur when calculating the life cycle cost and of the possible risk management. In the second part of the paper it is suggested that the motor vehicle life cycle cost can be predicted based on accurate data which are generally difficult to obtain, e.g. failure intensity z(t) or mean time between failures (MTBFs) used for calculating the cost after maintenance. The final part includes a proposal for the prediction of the ownership life cycle cost which consists of the operating and maintenance costs of special motor vehicles. This proposal is based on the company logistic information system, which at regular intervals assesses special vehicle life cycle cost during operation and maintenance. Under special motor vehicles here we understand the vehicles which are equipped with a chassis and a special vehicle superstructure which consumes operation units and on which maintenance is performed. Such vehicles are used in the construction or agricultural industry as well as in the military environment. The paper focuses on the design of a prediction model of the ownership life cycle cost of the military environment, where a relevant military logistic information system is used. [ABSTRACT FROM AUTHOR]

Changes in maintenance approaches of more complex vehicles and related systems are closely associated with the development of motor vehicles and the ever increasing demand for mobility. Ever since the production of the first motorized vehicles started, engineers have been addressing maintenance issues, which aim to maximize the reliability of vehicles and eliminate unwanted failures. The purpose of this article is to show how proactive maintenance can be performed. Proactive maintenance is based on on-line diagnostic systems in motor vehicles. In this paper, the authors describe the possibilities of obtaining operational data on automatic transmission from on-board diagnostics and its subsequent processing. Furthermore, the article presents a model proposed for determining the amount of wear of individual machine parts in an automatic transmission. Finally, a comparison of the data from the proposed model and the data from the CAN bus is made. The authors show the possibility of access in the field of sustainability towards proactive maintenance and the effort to predict future wear of machine parts in an automatic transmission using modelling. In this case, Matlab & Simulink software was used, which is suitable for these processes. This approach to the sustainability of motor vehicles is in principle identical or very similar to the systems used under various designations in industry, aviation, computer science, etc. [ABSTRACT FROM AUTHOR]

This paper focuses on determining the technical condition of a bearing box in the vehicle by means of vibrodiagnostics. In the next step, we determined the technical condition of roller bearings in the bearing box by measuring the vibration signal. One of the possibilities of determining the technical condition, including the location of accelerometers, the arrangement of relevant measured devices, and the analysis of frequency spectrum, is described in the paper. The aim of the experiment was to measure vibrations of the bearings placed in the vehicle bearing box and then to carry out the analysis of the measured data. The second part of the paper presents the analysis of samples of the plastic lubricant used for lubricating the tested roller bearings. For the analysis, we used an AES Spectroil Q100 device which works on the principle of atomic spectral analysis. [ABSTRACT FROM AUTHOR]

Vehicle's gearbox is regarded as one of the most crucial elements in a vehicle but it sustains a variety of faults such as a broken tooth, misalignment, imbalance, looseness, and even a broken case. Using accelerometers, which are mounted on the case to measure a vibration signal, we can detect faults and monitor the condition but the signals are often complicated and difficult to interpret. Moreover, it is costly and almost impossible to change the structure of a gearbox in order to survey, for instance, the dependence of a vibration signal on the structure, or types of a fault. In this paper a dynamic model of gearbox was developed with tooth breakage to study the capability of simulation using MSC.Adams software. In this simulation we focus on the gearbox used in a common military vehicle. The simulation was based on a nonlinear contact force to predict what happens to the gearbox in case the tooth breaks. The contact mechanics model of the meshing teeth is studied thoroughly by selecting contact simulation parameters such as stiffness, force exponent, damping and friction coefficients. To simulate the real working environment of the gearbox, simulated bearings were also built in the MSC. Adams. The paper shows that it is possible to simulate vibration signals by the gearbox model created in 3D CAD software and analyze the results in the multi-body dynamics software MSC.Adams. [ABSTRACT FROM AUTHOR]

In the paper there is a draft of a general model to be used for calculating life cycle costs and determining an optimum period of durability of a motor vehicle. This model is created in the MATLAB software environment. The paper contains calculations and input data which are necessary for making a model that would predict motor vehicle life cycle costs and determine the optimum period of durability. The suggested model might be used for working out life cycle costs of a new vehicle type for which the costs have not been determined yet. This model can also be applied when comparing several types of motor land vehicles of the same category during purchase. It is advisable to use the model mainly during tenders, since life cycle costs are one of the major criterion when selecting a supplier. The model enables us to calculate not only life cycle costs, but also vehicle amortization which depends upon mileage and age of a vehicle. All cumulative values might be transformed into unit values related to the mileage. [ABSTRACT FROM AUTHOR]

The paper addresses the issue of identifying the technical condition of rotating parts with by means of vibrodiagnostics. This method has been developing rapidly in recent years and it is conceived to be used for predicting failure occurrence. This enables us to determine an optimum time to perform machine preventive maintenance. The aim is to determine this point in time for groups of components, such as electric motors, gear boxes, and even combustion engines. In this paper, we focus on monitoring the technical condition of the medium truck bearing box on which we simulate different field conditions. A measuring device, DEWE 50/8, including the DEWEsoft software product of the Dewetron Company, has been used for the actual measurement. Along with the vibrodiagnostics used when determining the technical condition of the bearing box, we have also applied thermography for monitoring thermal changes of individual components. The aim of the research is to determine the moment when a preventive action is to be performed or when to change components before the failure occurs and increases the costs. [ABSTRACT FROM AUTHOR]

The article deals with temporary repairs. Applying a different technology, using a reproduction part, or performing a repair by a serviceman without the competence is typical features of temporary repairs. Temporary repair makes possible for an object to fulfill its function for a limited time, until regular repairs can be made. The complexity perplex modern vehicles their reparability. It is necessary to look for the new procedures of the implementation so-called temporary repairs. There is an analysis of temporary repairs in selected countries in NATO. The authors suggested procedure battle damage assessment and repair, which they expressed in the form of diagrams. The kit for battle damage for vehicles IVECO is described in the final part of the article. [ABSTRACT FROM AUTHOR]

The paper introduces a container workshop project of performing maintenance of The Czech Republic's land combat vehicles under field conditions. The presented workshop consists of two ISO 1C size range containers with special equipment. The first container is called a "working unit" and the other one is a "special purpose unit". During combat activities the containers would be arranged in L shape with rolled out roof. The article presents organization and technical conditions essential for implementation of the system of military equipment temporary repairs for military technical support's functioning. Furthermore, the article mentions such issues as unification and adjusting the equipment in a design and production processes, pro-active diagnostics, procedural conditionings, technology and temporary repair. Each issue is discussed considering possibilities and needs of temporary repairs system implementation. [ABSTRACT FROM AUTHOR]