Robert Basan | University of Rijeka (original) (raw)

Papers by Robert Basan

Proceedings of the 6th International Conference on Simulation and Modeling Methodologies, Technologies and Applications, 2016

Journal of Materials Engineering and Performance, 2016

ABSTRACT High transverse contact ratio gears (abbr. HCR-gears), are non-standard involute spur ge... more ABSTRACT High transverse contact ratio gears (abbr. HCR-gears), are non-standard involute spur gears with a transverse contact ratio εα > 2. This paper deals with the analysis and methods of determination of tooth root stresses in external HCR-gearing with theoretically accurate profile. Results of previously developed load sharing and tooth root stresses calculation method have been compared with the results of the DIN 3990 method and results of the finite element method contact analysis (FEA). Analysis has revealed that results of own calculation method are in good agreement with numericaly obtained values and it also confirmed that sugested method is significantly more accurate and reliable than standard DIN 3990 method.

Engineering Review, 2008

Ključne riječi: -monotoni parametri -ponašanje materijala -čelik 42CrMo4 -tvrdoća Abstract: The p... more Ključne riječi: -monotoni parametri -ponašanje materijala -čelik 42CrMo4 -tvrdoća Abstract: The presented work is concerned primarily with experimental determination of the behaviour of normalised and quenched and tempered low-alloy steel 42CrMo4 (AISI4140) subjected to monotonic uniaxial tensile loading and determination of its monotonic parameters. Experiments were performed on standard specimens using a servohydraulic testing machine at room temperature. The behaviours of materials with differing hardnesses were analyzed and compared. After determination of principal monotonic parameters values, correlation was confirmed to exist between tempering temperature, i.e. achieved materials' hardness, and the monotonic yield strength as well as the ultimate strength. Simple expressions are proposed for fast estimation of cited monotonic properties from hardness.

International Journal of Fatigue, Mar 1, 2011

Strain-life fatigue parameters of unalloyed steels, low-alloy steels, high-alloy steels, aluminiu... more Strain-life fatigue parameters of unalloyed steels, low-alloy steels, high-alloy steels, aluminium alloys and titanium alloys and their strain-life behaviour across low-cycle, medium-cycle and high-cycle fatigue range were analyzed. Substantial differences were found to exist both among fatigue parameters and among De/2 À 2N f relationships of materials belonging to these main metallic materials groups. This turns out to be in contrast with the fact that most of the existing methods for the estimation of strainlife fatigue parameters from monotonic properties show rather limited regard as to which group material in question belongs to. From results of the analysis it can be concluded that in estimation of strain-life fatigue parameters differential approach might be desirable, i.e. that separate expressions should be developed for every material group. It is expected that such an approach and resulting expressions could result in more accurate estimations of fatigue parameters and hence, more accurate estimations of time to crack initiation. In Universal slopes method [6] Manson proposed r 0 f to be estimated from ultimate strength R m ; e 0 f from true fracture ductility e f , while to both exponents b and c constant values were assigned. Same author in his Four-point correlation method [6] proposed more intricate expressions which are based on estimates of elastic De e /2, i.e. plastic strain amplitudes De p /2 at four different numbers of loading cycles (N = 1/4, 10, 10 4 , 10 5 ). According to Mitchell's method [7], both r 0 f and b can be estimated from R m while e f presents the basis for calculation of e 0

High transverse contact ratio gears (abbr. HCR gears) are non-standard spur gears with a transver... more High transverse contact ratio gears (abbr. HCR gears) are non-standard spur gears with a transverse contact ratio 2<ε α <3. This paper deals with the influence of various geometrical parameters such as pressure angle, tooth height, teeth number, transmission ratio, addendum modification coefficients sum and its distribution on the value of force acting on teeth pair in the relevant contact point. The influence of these parameters on mentioned force calculated according to the theoretical load distribution was determined. The analisys resulted with diagrams and analytical expressions which quantify the dependence of the relevant tooth force on the geometry of HCR gears.

HCR involute gears (transverse contact ratio ε α > 2) have bigger load capacity but also worse... more HCR involute gears (transverse contact ratio ε α > 2) have bigger load capacity but also worse sliding conditions between teeth flanks in comparison to standard LCR gears. These factors are very important and must be considered early in the design process. This paper deals primarily with the influence of normal pressure angle α n , basic rack profile tooth addendum height h aP and transverse contact ratio ε α on HCR-gears' load carrying capacity and efficiency. Results are presented in form of 3D diagrams which can serve as design and tribological guidelines for optimal choice of HCR-gears geometry.

High transverse contact ratio (HCR) gears are non-standard involute gears with a transverse conta... more High transverse contact ratio (HCR) gears are non-standard involute gears with a transverse contact ratio εα > 2 which proved adequate for use in automobiles, trucks, aircrafts and ships. The paper deals with the dependence of the sliding friction losses on HCR spur gears geometry such as pressure angle, tooth height, gears centre distance resp. addendum modification coefficients sum, addendum modification coefficients sum distribution and other parameters. The calculations are based on the comparison between the values of the sliding friction loss geometrical factor, which comprises the influence of the magnitude, and form of the toothing. A proper choice of these parameters is necessary for achieving good gearbox efficiency. The calculations results are shown in diagrams which can be a tribological guideline to a designer in choosing gears optimal geometrical parameters.

This article describes investigations into the existence of correlation between experimentally de... more This article describes investigations into the existence of correlation between experimentally determined cyclic parameters and hardness of quenched and tempered representative low-alloy steel 42CrMo4. A good correlation was found to exist between cyclic strength coefficient K’ and Brinell hardness HB, but not between cyclic strain hardening exponent n‘ and hardness HB. Nevertheless, good agreement between calculated and experimental cyclic stress-strain curves shows that cyclic parameters i.e. cyclic stress-strain curves of the investigated steel can be successfully estimated from its hardness.

Although significant number of commercial software packages for calculation, analysis and design ... more Although significant number of commercial software packages for calculation, analysis and design of wide vari-ety of mechanical elements are available today, development of own, custom software solutions remains very important. Usualy in the framework of scientific work, custom applications with novel techniques and solutions get developed but often remain in form which is unsuitable for wider, practical use. Additional development of user-friendly environment, user-interface and necessary documentation often reveals itself to be the critical step in achieving wider acceptance of such tools and solutions. Such custom developed solutions offer good control over implemented methodology and procedures and the way calculations are performed, greater flexibility and easy subsequent implementation of neccessary improvements and modifications. An example of own, custom-developed software application for gear design and modelling with its possibilities and options is presented.

High transverse contact ratio (HCR) gears are more frequently in use because of their increased l... more High transverse contact ratio (HCR) gears are more frequently in use because of their increased load-carrying capacity compared to low contact ratio gears, although they are very sensitive to manufacturing errors. The calculation procedure of load distribution, established for HCR gears with pitch errors, depends on the position of tooth pairs, with regard to pitch error. The critical position of tooth pairs, which causes the maximum stress increase, compared to geometrically ideal gears, is defined in this paper.

Procedia Engineering, 2015

ABSTRACT In order to address problems connected with the choice of a proper material during early... more ABSTRACT In order to address problems connected with the choice of a proper material during early stages of product development when limited or no experimental data on candidate materials are available, a web-based information system consisting of material properties database and expert system for the estimation of cyclic and fatigue material parameters has been established. Material properties database is user-expandable and draws mainly on existing, published literature sources and results of relevant research. Besides the well-established estimation methods and the methodology for their evaluation, the results of own research in the form of a newly proposed approach and method for the estimation of strain-life fatigue parameters as well as the methodology for the evaluation of estimation methods are incorporated in the system as well.

Procedia Engineering, 2011

International Journal of Fatigue, 2011

Computational Materials Science, 2010

ABSTRACT Modeling of material behaviour has significant influence on design and optimization of m... more ABSTRACT Modeling of material behaviour has significant influence on design and optimization of mechanical struc-tures and consequently calculation of their lifetime. When using complex constitutive material model that describes elastic–plastic behaviour of the cyclically loaded material and takes into account damage occurrence and accumulation, the process of parameter identification from experimental data is very complex and time-consuming. In this paper the damage occurrence and accumulation within the material are described by means of models of Bauschinger effect, kinematic and isotropic hardening (or softening) according to Chaboche material model and mean stress relaxation according to Ohno–Wang material model. Since the material model is highly non-linear, its parameter identification requires complex numerical procedures, carefully chosen algorithms and numerical operators, followed by software solution development. The developed automated system for material model parameter identification is validated by comparing the calculated with experimental response of the material. Its usage can make material behaviour modeling for numerous materials accurate, fast and user-friendly.

Computational Materials Science, 2009

The material model presented in this paper describes elasto-plastic behaviour of the material und... more The material model presented in this paper describes elasto-plastic behaviour of the material under a cyclic load application. It takes into account damage occurrence and accumulation in the material and it's relation to isotropic and kinematic hardening or softening. The material constitutive model for description of low-cycle fatigue behaviour is highly non-linear and therefore its parameter identification requires complex numerical procedure, such as genetic algorithm (GA). Because of its complexity, the unique genetic operators' routines in GA calculation procedure are developed to make possible fast and reliable convergence to the results. These routines are incorporated in developed software solution. The calculation resulted in identification of material parameters that are validated in comparing material response of numerical solution with experimental data.

11th International Conference on Machine Design …, 2004

Procedia Engineering, Jan 1, 2010