The history of the Faculty of Electrical Engineering, Mechanical Engineering and Naval Architectu... more The history of the Faculty of Electrical Engineering, Mechanical Engineering and Naval Architecture in Split (FESB abbreviated in Croatian) begins in 1960 when the Faculty of Electrical Engineering becomes entirely autonomous and independent unit of the University of Zagreb. Five years later Mechanical and Technological Department was founded at the Faculty of Electrical Engineering in Split, offering two first years of study in the area of Mechanical Engineering. Also, this study programme provided students to continue the Mechanical Engineering programme in Zagreb after the fourth semester. Furthermore, the Naval Architecture study programme was established at the Department of Mechanical Engineering in year 1968. The Faculty was renamed as the Faculty of Electrical Engineering, Mechanical Engineering and Naval Architecture in Split in 1971, while in 1974 the Faculty became a constituent part of the newly established University of Split. The Faculty is referred to be as one of the University founders. The full four-year Mechanical Engineering programme of study was established in 1976. In the meantime, two new undergraduate study programmes were established in 2002: Computer sci
The main goal in designing the wind turbine is ensuring structural safety and optimal operational... more The main goal in designing the wind turbine is ensuring structural safety and optimal operational performance. Key aspects to be addressed are: long design life, sensitivity of structure to vibration and resonance, non- deterministic wind loads with significant time variations and micro-location dependence. In order to achieve these goals, a simple dynamic lumped-mass model of a conic tubular steel wind turbine tower has been developed in this paper. The tower stiffness matrix is determined by considering the stiffness of a cantilever beam with variable cross-section, and lumped masses for each conical segment are determined in such a way that the centres of gravity of conical segments match their actual position in the structure. There is a very good agreement between the measured field data and the results obtained by the developed simple numerical model.
Hydraulic systems provide good dynamic behaviour and therefore are one of the main design concept... more Hydraulic systems provide good dynamic behaviour and therefore are one of the main design concept for industrial applications, such as the example of drives for machine tools. The most important part of the hydraulic system is the pump. The main task of the pump is the converting mechanical energy from the prime mover into hydraulic energy, or the flow and pressure, with as high efficiency as possible. The paper shows the experimental determination of the actual flow rate of one type of the external gear pump, depending on the load condition. The analysis of test results shows the linear dependence of the actual flow rate of the pump and the discharge pressure. On the basis of the mathematical model, the volumetric efficiency values of the pump are obtained. They deviate from about 1 % of the experimentally determined values, which justifies the applied model. The presented model can be the basis for the simulation as in the example shown in this paper, while the experimental model ...
Cetiri fakulteta izvode studije strojarstva u Republici Hrvatskoj: Fakultet strojarstva i brodogr... more Cetiri fakulteta izvode studije strojarstva u Republici Hrvatskoj: Fakultet strojarstva i brodogradnje, Sveuciliste u Zagrebu, Fakultet elektrotehnike, strojarstva i brodogradnje, Sveuciliste u Splitu, Strojarski fakultet u Slavonskom Brodu, Sveuciliste Josipa Jurja Strossmayera u Osijeku i Tehnicki fakultet, Sveuciliste u Rijeci. Svi fakulteti ustrojeni su na nacin da osiguravaju kvalitetno izvođenje nastave i izobrazbu studenata na preddiplomskoj, diplomskoj i doktorskoj razini. U posljednje vrijeme sve se vise primjecuje potreba za normiranjem kompetencija inženjera strojarstva radi olaksavanja mobilnosti studenata, ostvarenja bolje prepoznatljivosti prvostupnika i magistara inženjera te doktora znanosti u ovom podrucju, a sto je moguce ostvariti uređenjem sustava kvalifikacija kroz Hrvatski kvalifikacijski okvir. U okviru aktivnosti na projektu ME4CataLOgue, stoga se prislo izradi kataloga znanja, vjestina i kompetencija za studije strojarstva u Republici Hrvatskoj. U ovom radu ...
Service strength approval of a drillship derrick must include beside the static strength validati... more Service strength approval of a drillship derrick must include beside the static strength validation under limit loads, also the fatigue evaluation for the critical areas of the derrick structure. During the service life structural members of the derrick are exposed to giga stress cycles with variable values, caused by wave and wind action and drilling operation. These variable stresses can generate the fatigue cracks and lead to the total fracture of the structure. For the fatigue strength evaluation of a drillship derrick is important to define the loading taking into account the drillship usage. To determine the loading it is necessary to evaluate the ship motion and to calculate the corresponding loads due to waves, wind and drilling operation acting on the derrick structure. For the fatigue life validation, the resulting stresses, caused by these loads must be determined and their representative spectra (cumulative frequency distributions) derived. In this paper the procedure to...
An outline of the Timoshenko beam theory, which deals with deflection and cross-section rotation ... more An outline of the Timoshenko beam theory, which deals with deflection and cross-section rotation as the basic variables, is presented. It is modified by decomposing total deflection into pure bending deflection and shear deflection, and total rotation into bending rotation and axial shear angle. The governing equations are condensed into two independent equations of motion, one for flexural and another for axial shear vibrations. The solution is given for natural vibrations. Nonlocal stress parameter is taken into account for vibration analysis of nanotube embedded in an elastic medium. The 4 th order partial differential equation for flexural vibration is extended to the 6 th order one. Nanotube response to moving nanoparticle gravity load is analyzed by employing modal superposition method, separation of variables, Galerkin method and harmonic balance method. In addition coupled flexural and torsional vibrations of a thin-walled girder are considered. The modified Timoshenko beam theory is applied for flexural vibrations while the complex torsional beam theory with warping cross-section is worked out in an analogical way. For vibration analysis of nonprismatic ship hull an advanced beam finite element is created. Application of the developed theory is illustrated in the case of nanotube and ultra large container ship vibrations.
Cetiri fakulteta izvode studije strojarstva u Republici Hrvatskoj: Fakultet strojarstva i brodogr... more Cetiri fakulteta izvode studije strojarstva u Republici Hrvatskoj: Fakultet strojarstva i brodogradnje, Sveuciliste u Zagrebu, Fakultet elektrotehnike, strojarstva i brodogradnje, Sveuciliste u Splitu, Strojarski fakultet u Slavonskom Brodu, Sveuciliste Josipa Jurja Strossmayera u Osijeku i Tehnicki fakultet, Sveuciliste u Rijeci. Svi fakulteti ustrojeni su na nacin da osiguravaju kvalitetno izvođenje nastave i izobrazbu studenata na preddiplomskoj, diplomskoj i doktorskoj razini. U posljednje vrijeme sve se vise primjecuje potreba za normiranjem kompetencija inženjera strojarstva radi olaksavanja mobilnosti studenata, ostvarenja bolje prepoznatljivosti prvostupnika i magistara inženjera te doktora znanosti u ovom podrucju, a sto je moguce ostvariti uređenjem sustava kvalifikacija kroz Hrvatski kvalifikacijski okvir. U okviru aktivnosti na projektu ME4CataLOgue, stoga se prislo izradi kataloga znanja, vjestina i kompetencija za studije strojarstva u Republici Hrvatskoj. U ovom radu ...
This paper addresses the Coulomb dry friction force as a technical indicator for fast and efficie... more This paper addresses the Coulomb dry friction force as a technical indicator for fast and efficient condition-based maintenance. To estimate the value of friction force, the Bayesian analysis is used. Instead of the complex Markov Chain Monte Carlo numerical method, a closed-form analytical solution is applied. Thus, a simple and efficient procedure for friction estimation is described. Such a solution in the Bayesian context is known as the conjugate prior. The procedure presented here is verified numerically and experimentally by directly comparing the estimated value with the measured one. Two families of conjugate priors, the gamma-exponential and the normal-gamma, are compared. It is shown that the latter is suitable for friction estimation. An additional parameter, the precision parameter, was proposed as a criterion for the acceptance of estimation.
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Our Sea International Journal of Maritime Science Technology, Oct 31, 2008
Brodski porivni i pomoćni strojevi temelje se kruto (na metalnim, ili podlogama od smole) ili ela... more Brodski porivni i pomoćni strojevi temelje se kruto (na metalnim, ili podlogama od smole) ili elastično (na elastičnim podlogama s gumenim dijelovima). Osnovna je svrha elastičnog temeljenja smanjiti nepovoljan utjecaj vibracija i neposredan prijenos buke izazvane radom strojeva na brodsku konstrukciju. Elastično se temeljenje zbog toga često rabi na putničkim brodovima. Cilj je u ovom radu prikazati pojednostavnjeni postupak proračuna elastičnog temeljenja brodskih strojeva kako bi se olakšao rad projektantima brodskih pogonskih i pomoćnih sustava. Pojednostavnjeni se proračun u osnovi svodi na određivanje statičkih sila u elastičnim podlogama, a zatim i prirodnih frekvencija sustava sa šest stupnjeva slobode, iz kojih se dobivaju kritične brzine vrtnje. Proračun je prikazan matrično (analogno metodi konačnih elemenata za deformabilne sustave) s pojedinostima potrebnim projektantu za samostalan rad. Načelno je prikazana i metodologija proračuna prisilnih prigušenih vibracija, to jest uzbudnih sila i posljedičnih dinamičkih odziva sustava. Doprinos je rada u matrično sažetoj metodologiji proračuna, te u prijedlogu izbjegavanja izračuna uzbudnih sila. Naime, u izvjesnim uvjetima, dostatno je poznavati samo ritam (frekvenciju) uzbude izazvanu radom motora s unutarnjim izgaranjem i brodskoga vijka, a ne i njezinu veličinu ili fazu, te u Campbellovu dijagramu usporediti tu frekvenciju s izračunatim prirodnim frekvencijama sustava. Tako se odlučuje je li složeniji pristup potreban ili ne. Prikazan je primjer rezultata proračuna za porivni sustav više putničkih brodova izgrađenih u domaćem brodogradilištu, uz usporedbu s rezultatima mjerenja iz literature na prvom brodu. Zaključuje se da proračun elastičnog temeljenja ne treba izbjegavati u praksi, što je često, nego primjenom predloženoga jednostavnog postupka provesti potrebne statičke i dinamičke analize. Tako se dovoljno rano u projektnoj fazi mogu predvidjeti i riješiti poteškoće koje je poslije bilo teško otklanjati.
Nase More Znanstveno Strucni Casopis Za More I Pomorstvo, Oct 31, 2008
Brodski porivni i pomoćni strojevi temelje se kruto (na metalnim, ili podlogama od smole) ili ela... more Brodski porivni i pomoćni strojevi temelje se kruto (na metalnim, ili podlogama od smole) ili elastično (na elastičnim podlogama s gumenim dijelovima). Osnovna je svrha elastičnog temeljenja smanjiti nepovoljan utjecaj vibracija i neposredan prijenos buke izazvane radom strojeva na brodsku konstrukciju. Elastično se temeljenje zbog toga često rabi na putničkim brodovima. Cilj je u ovom radu prikazati pojednostavnjeni postupak proračuna elastičnog temeljenja brodskih strojeva kako bi se olakšao rad projektantima brodskih pogonskih i pomoćnih sustava. Pojednostavnjeni se proračun u osnovi svodi na određivanje statičkih sila u elastičnim podlogama, a zatim i prirodnih frekvencija sustava sa šest stupnjeva slobode, iz kojih se dobivaju kritične brzine vrtnje. Proračun je prikazan matrično (analogno metodi konačnih elemenata za deformabilne sustave) s pojedinostima potrebnim projektantu za samostalan rad. Načelno je prikazana i metodologija proračuna prisilnih prigušenih vibracija, to jest uzbudnih sila i posljedičnih dinamičkih odziva sustava. Doprinos je rada u matrično sažetoj metodologiji proračuna, te u prijedlogu izbjegavanja izračuna uzbudnih sila. Naime, u izvjesnim uvjetima, dostatno je poznavati samo ritam (frekvenciju) uzbude izazvanu radom motora s unutarnjim izgaranjem i brodskoga vijka, a ne i njezinu veličinu ili fazu, te u Campbellovu dijagramu usporediti tu frekvenciju s izračunatim prirodnim frekvencijama sustava. Tako se odlučuje je li složeniji pristup potreban ili ne. Prikazan je primjer rezultata proračuna za porivni sustav više putničkih brodova izgrađenih u domaćem brodogradilištu, uz usporedbu s rezultatima mjerenja iz literature na prvom brodu. Zaključuje se da proračun elastičnog temeljenja ne treba izbjegavati u praksi, što je često, nego primjenom predloženoga jednostavnog postupka provesti potrebne statičke i dinamičke analize. Tako se dovoljno rano u projektnoj fazi mogu predvidjeti i riješiti poteškoće koje je poslije bilo teško otklanjati.
Advanced Ship Design for Pollution Prevention, 2010
The use of reliability models is often limited by a lack of satisfactory data for the estimates o... more The use of reliability models is often limited by a lack of satisfactory data for the estimates of system parameters. This paper discusses the problem of life cycle management with insufficient failure record of the equipment. This deficiency is addressed by using expert opinion and Bayesian modeling. The framework for Bayesian updating of the reliability models is presented and the different aspects of updating process are discussed. The use of expert opinion, generic data and the types of uncertainties associated is presented. Since the most of the generic data provides only constant failure rate, updating process for the exponential sampling distribution is described in detail.
The history of the Faculty of Electrical Engineering, Mechanical Engineering and Naval Architectu... more The history of the Faculty of Electrical Engineering, Mechanical Engineering and Naval Architecture in Split (FESB abbreviated in Croatian) begins in 1960 when the Faculty of Electrical Engineering becomes entirely autonomous and independent unit of the University of Zagreb. Five years later Mechanical and Technological Department was founded at the Faculty of Electrical Engineering in Split, offering two first years of study in the area of Mechanical Engineering. Also, this study programme provided students to continue the Mechanical Engineering programme in Zagreb after the fourth semester. Furthermore, the Naval Architecture study programme was established at the Department of Mechanical Engineering in year 1968. The Faculty was renamed as the Faculty of Electrical Engineering, Mechanical Engineering and Naval Architecture in Split in 1971, while in 1974 the Faculty became a constituent part of the newly established University of Split. The Faculty is referred to be as one of the University founders. The full four-year Mechanical Engineering programme of study was established in 1976. In the meantime, two new undergraduate study programmes were established in 2002: Computer sci
The main goal in designing the wind turbine is ensuring structural safety and optimal operational... more The main goal in designing the wind turbine is ensuring structural safety and optimal operational performance. Key aspects to be addressed are: long design life, sensitivity of structure to vibration and resonance, non- deterministic wind loads with significant time variations and micro-location dependence. In order to achieve these goals, a simple dynamic lumped-mass model of a conic tubular steel wind turbine tower has been developed in this paper. The tower stiffness matrix is determined by considering the stiffness of a cantilever beam with variable cross-section, and lumped masses for each conical segment are determined in such a way that the centres of gravity of conical segments match their actual position in the structure. There is a very good agreement between the measured field data and the results obtained by the developed simple numerical model.
Hydraulic systems provide good dynamic behaviour and therefore are one of the main design concept... more Hydraulic systems provide good dynamic behaviour and therefore are one of the main design concept for industrial applications, such as the example of drives for machine tools. The most important part of the hydraulic system is the pump. The main task of the pump is the converting mechanical energy from the prime mover into hydraulic energy, or the flow and pressure, with as high efficiency as possible. The paper shows the experimental determination of the actual flow rate of one type of the external gear pump, depending on the load condition. The analysis of test results shows the linear dependence of the actual flow rate of the pump and the discharge pressure. On the basis of the mathematical model, the volumetric efficiency values of the pump are obtained. They deviate from about 1 % of the experimentally determined values, which justifies the applied model. The presented model can be the basis for the simulation as in the example shown in this paper, while the experimental model ...
Cetiri fakulteta izvode studije strojarstva u Republici Hrvatskoj: Fakultet strojarstva i brodogr... more Cetiri fakulteta izvode studije strojarstva u Republici Hrvatskoj: Fakultet strojarstva i brodogradnje, Sveuciliste u Zagrebu, Fakultet elektrotehnike, strojarstva i brodogradnje, Sveuciliste u Splitu, Strojarski fakultet u Slavonskom Brodu, Sveuciliste Josipa Jurja Strossmayera u Osijeku i Tehnicki fakultet, Sveuciliste u Rijeci. Svi fakulteti ustrojeni su na nacin da osiguravaju kvalitetno izvođenje nastave i izobrazbu studenata na preddiplomskoj, diplomskoj i doktorskoj razini. U posljednje vrijeme sve se vise primjecuje potreba za normiranjem kompetencija inženjera strojarstva radi olaksavanja mobilnosti studenata, ostvarenja bolje prepoznatljivosti prvostupnika i magistara inženjera te doktora znanosti u ovom podrucju, a sto je moguce ostvariti uređenjem sustava kvalifikacija kroz Hrvatski kvalifikacijski okvir. U okviru aktivnosti na projektu ME4CataLOgue, stoga se prislo izradi kataloga znanja, vjestina i kompetencija za studije strojarstva u Republici Hrvatskoj. U ovom radu ...
Service strength approval of a drillship derrick must include beside the static strength validati... more Service strength approval of a drillship derrick must include beside the static strength validation under limit loads, also the fatigue evaluation for the critical areas of the derrick structure. During the service life structural members of the derrick are exposed to giga stress cycles with variable values, caused by wave and wind action and drilling operation. These variable stresses can generate the fatigue cracks and lead to the total fracture of the structure. For the fatigue strength evaluation of a drillship derrick is important to define the loading taking into account the drillship usage. To determine the loading it is necessary to evaluate the ship motion and to calculate the corresponding loads due to waves, wind and drilling operation acting on the derrick structure. For the fatigue life validation, the resulting stresses, caused by these loads must be determined and their representative spectra (cumulative frequency distributions) derived. In this paper the procedure to...
An outline of the Timoshenko beam theory, which deals with deflection and cross-section rotation ... more An outline of the Timoshenko beam theory, which deals with deflection and cross-section rotation as the basic variables, is presented. It is modified by decomposing total deflection into pure bending deflection and shear deflection, and total rotation into bending rotation and axial shear angle. The governing equations are condensed into two independent equations of motion, one for flexural and another for axial shear vibrations. The solution is given for natural vibrations. Nonlocal stress parameter is taken into account for vibration analysis of nanotube embedded in an elastic medium. The 4 th order partial differential equation for flexural vibration is extended to the 6 th order one. Nanotube response to moving nanoparticle gravity load is analyzed by employing modal superposition method, separation of variables, Galerkin method and harmonic balance method. In addition coupled flexural and torsional vibrations of a thin-walled girder are considered. The modified Timoshenko beam theory is applied for flexural vibrations while the complex torsional beam theory with warping cross-section is worked out in an analogical way. For vibration analysis of nonprismatic ship hull an advanced beam finite element is created. Application of the developed theory is illustrated in the case of nanotube and ultra large container ship vibrations.
Cetiri fakulteta izvode studije strojarstva u Republici Hrvatskoj: Fakultet strojarstva i brodogr... more Cetiri fakulteta izvode studije strojarstva u Republici Hrvatskoj: Fakultet strojarstva i brodogradnje, Sveuciliste u Zagrebu, Fakultet elektrotehnike, strojarstva i brodogradnje, Sveuciliste u Splitu, Strojarski fakultet u Slavonskom Brodu, Sveuciliste Josipa Jurja Strossmayera u Osijeku i Tehnicki fakultet, Sveuciliste u Rijeci. Svi fakulteti ustrojeni su na nacin da osiguravaju kvalitetno izvođenje nastave i izobrazbu studenata na preddiplomskoj, diplomskoj i doktorskoj razini. U posljednje vrijeme sve se vise primjecuje potreba za normiranjem kompetencija inženjera strojarstva radi olaksavanja mobilnosti studenata, ostvarenja bolje prepoznatljivosti prvostupnika i magistara inženjera te doktora znanosti u ovom podrucju, a sto je moguce ostvariti uređenjem sustava kvalifikacija kroz Hrvatski kvalifikacijski okvir. U okviru aktivnosti na projektu ME4CataLOgue, stoga se prislo izradi kataloga znanja, vjestina i kompetencija za studije strojarstva u Republici Hrvatskoj. U ovom radu ...
This paper addresses the Coulomb dry friction force as a technical indicator for fast and efficie... more This paper addresses the Coulomb dry friction force as a technical indicator for fast and efficient condition-based maintenance. To estimate the value of friction force, the Bayesian analysis is used. Instead of the complex Markov Chain Monte Carlo numerical method, a closed-form analytical solution is applied. Thus, a simple and efficient procedure for friction estimation is described. Such a solution in the Bayesian context is known as the conjugate prior. The procedure presented here is verified numerically and experimentally by directly comparing the estimated value with the measured one. Two families of conjugate priors, the gamma-exponential and the normal-gamma, are compared. It is shown that the latter is suitable for friction estimation. An additional parameter, the precision parameter, was proposed as a criterion for the acceptance of estimation.
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Our Sea International Journal of Maritime Science Technology, Oct 31, 2008
Brodski porivni i pomoćni strojevi temelje se kruto (na metalnim, ili podlogama od smole) ili ela... more Brodski porivni i pomoćni strojevi temelje se kruto (na metalnim, ili podlogama od smole) ili elastično (na elastičnim podlogama s gumenim dijelovima). Osnovna je svrha elastičnog temeljenja smanjiti nepovoljan utjecaj vibracija i neposredan prijenos buke izazvane radom strojeva na brodsku konstrukciju. Elastično se temeljenje zbog toga često rabi na putničkim brodovima. Cilj je u ovom radu prikazati pojednostavnjeni postupak proračuna elastičnog temeljenja brodskih strojeva kako bi se olakšao rad projektantima brodskih pogonskih i pomoćnih sustava. Pojednostavnjeni se proračun u osnovi svodi na određivanje statičkih sila u elastičnim podlogama, a zatim i prirodnih frekvencija sustava sa šest stupnjeva slobode, iz kojih se dobivaju kritične brzine vrtnje. Proračun je prikazan matrično (analogno metodi konačnih elemenata za deformabilne sustave) s pojedinostima potrebnim projektantu za samostalan rad. Načelno je prikazana i metodologija proračuna prisilnih prigušenih vibracija, to jest uzbudnih sila i posljedičnih dinamičkih odziva sustava. Doprinos je rada u matrično sažetoj metodologiji proračuna, te u prijedlogu izbjegavanja izračuna uzbudnih sila. Naime, u izvjesnim uvjetima, dostatno je poznavati samo ritam (frekvenciju) uzbude izazvanu radom motora s unutarnjim izgaranjem i brodskoga vijka, a ne i njezinu veličinu ili fazu, te u Campbellovu dijagramu usporediti tu frekvenciju s izračunatim prirodnim frekvencijama sustava. Tako se odlučuje je li složeniji pristup potreban ili ne. Prikazan je primjer rezultata proračuna za porivni sustav više putničkih brodova izgrađenih u domaćem brodogradilištu, uz usporedbu s rezultatima mjerenja iz literature na prvom brodu. Zaključuje se da proračun elastičnog temeljenja ne treba izbjegavati u praksi, što je često, nego primjenom predloženoga jednostavnog postupka provesti potrebne statičke i dinamičke analize. Tako se dovoljno rano u projektnoj fazi mogu predvidjeti i riješiti poteškoće koje je poslije bilo teško otklanjati.
Nase More Znanstveno Strucni Casopis Za More I Pomorstvo, Oct 31, 2008
Brodski porivni i pomoćni strojevi temelje se kruto (na metalnim, ili podlogama od smole) ili ela... more Brodski porivni i pomoćni strojevi temelje se kruto (na metalnim, ili podlogama od smole) ili elastično (na elastičnim podlogama s gumenim dijelovima). Osnovna je svrha elastičnog temeljenja smanjiti nepovoljan utjecaj vibracija i neposredan prijenos buke izazvane radom strojeva na brodsku konstrukciju. Elastično se temeljenje zbog toga često rabi na putničkim brodovima. Cilj je u ovom radu prikazati pojednostavnjeni postupak proračuna elastičnog temeljenja brodskih strojeva kako bi se olakšao rad projektantima brodskih pogonskih i pomoćnih sustava. Pojednostavnjeni se proračun u osnovi svodi na određivanje statičkih sila u elastičnim podlogama, a zatim i prirodnih frekvencija sustava sa šest stupnjeva slobode, iz kojih se dobivaju kritične brzine vrtnje. Proračun je prikazan matrično (analogno metodi konačnih elemenata za deformabilne sustave) s pojedinostima potrebnim projektantu za samostalan rad. Načelno je prikazana i metodologija proračuna prisilnih prigušenih vibracija, to jest uzbudnih sila i posljedičnih dinamičkih odziva sustava. Doprinos je rada u matrično sažetoj metodologiji proračuna, te u prijedlogu izbjegavanja izračuna uzbudnih sila. Naime, u izvjesnim uvjetima, dostatno je poznavati samo ritam (frekvenciju) uzbude izazvanu radom motora s unutarnjim izgaranjem i brodskoga vijka, a ne i njezinu veličinu ili fazu, te u Campbellovu dijagramu usporediti tu frekvenciju s izračunatim prirodnim frekvencijama sustava. Tako se odlučuje je li složeniji pristup potreban ili ne. Prikazan je primjer rezultata proračuna za porivni sustav više putničkih brodova izgrađenih u domaćem brodogradilištu, uz usporedbu s rezultatima mjerenja iz literature na prvom brodu. Zaključuje se da proračun elastičnog temeljenja ne treba izbjegavati u praksi, što je često, nego primjenom predloženoga jednostavnog postupka provesti potrebne statičke i dinamičke analize. Tako se dovoljno rano u projektnoj fazi mogu predvidjeti i riješiti poteškoće koje je poslije bilo teško otklanjati.
Advanced Ship Design for Pollution Prevention, 2010
The use of reliability models is often limited by a lack of satisfactory data for the estimates o... more The use of reliability models is often limited by a lack of satisfactory data for the estimates of system parameters. This paper discusses the problem of life cycle management with insufficient failure record of the equipment. This deficiency is addressed by using expert opinion and Bayesian modeling. The framework for Bayesian updating of the reliability models is presented and the different aspects of updating process are discussed. The use of expert opinion, generic data and the types of uncertainties associated is presented. Since the most of the generic data provides only constant failure rate, updating process for the exponential sampling distribution is described in detail.
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Papers by Jani Barle