Dijetni problem jedan je od najstarijih problema optimalizacije. Cilj je odabrati određenu kolici... more Dijetni problem jedan je od najstarijih problema optimalizacije. Cilj je odabrati određenu kolicinu namirnica koja ce zadovoljiti nutritivne potrebe uz najmanju cijenu promatranog obroka. U ovom je radu dijetni problem upotrijebljen sa svrhom optimalizacije studentske prehrane na Sveucilistu u Splitu. Cilj je minimalizirati energetsku vrijednost složenog obroka - rucka. Nakon prikupljanja podataka i provedene statisticke analize razmatrano je zadovoljavanje nutritivnih potreba na primjeru deset razlicitih obroka. Slijedilo je definiranje matematickog modela: varijabli odlucivanja i funkcije cilja te, obzirom na propisane namirnice i nutritivne zahtjeve, potrebna ogranicenja u vidu nejednadžbi. Problem je rijesen uz pomoc MS Excel-ovog alata Solver. Provedena je analiza osjetljivosti. Predložena su optimalna rjesenja.
Summary The theory of torsion of thin walled beams of open cross-sections with influence of shear... more Summary The theory of torsion of thin walled beams of open cross-sections with influence of shear on the basis of the classical Vlasov’s theory of thin-walled beams of open cross-sections for beams with single and double symmetrical cross-sections is developed. It is proved that the beam subjected to torsion with influence of shear exerted by couples in the beam crosssections is also subjected to bending due to shear in the plane orthogonal to the plane of symmetry. The beam is subjected to torsion with influence of shear only in the case of double symmetrical cross-sections. The principal cross-section axes as well as the principal pole are defined according to the classical theory of thin-walled beams of open sections. Illustrative examples are given, as well as a comparison with the finite element method.
This paper discusses the torsion and bending of a thin-walled girder of open cross-section, where... more This paper discusses the torsion and bending of a thin-walled girder of open cross-section, where the torsional stiffness is low compared to the warping stiffness. A computer program is given for the plane system of a thin-walled girder of open section. The modelling of plated structures by thin-walled girders of open section for ship's bottom structures is illustrated. The results were verified by finite element method, employing membrane elements.
A computer program with graphical user interface for the determination of the geometrical propert... more A computer program with graphical user interface for the determination of the geometrical properties of arbitrary thin-walled cross-section: open, closed-open and closed is presented. Both numerical and graphical outputs are enabled. The directions of corresponding shear flows are shown. The program calculates integrals for determination of shear factors as well. Obtained results are compared with those in published articles.
Dijetni problem jedan je od najstarijih problema optimalizacije. Cilj je odabrati određenu kolici... more Dijetni problem jedan je od najstarijih problema optimalizacije. Cilj je odabrati određenu kolicinu namirnica koja ce zadovoljiti nutritivne potrebe uz najmanju cijenu promatranog obroka. U ovom je radu dijetni problem upotrijebljen sa svrhom optimalizacije studentske prehrane na Sveucilistu u Splitu. Cilj je minimalizirati energetsku vrijednost složenog obroka - rucka. Nakon prikupljanja podataka i provedene statisticke analize razmatrano je zadovoljavanje nutritivnih potreba na primjeru deset razlicitih obroka. Slijedilo je definiranje matematickog modela: varijabli odlucivanja i funkcije cilja te, obzirom na propisane namirnice i nutritivne zahtjeve, potrebna ogranicenja u vidu nejednadžbi. Problem je rijesen uz pomoc MS Excel-ovog alata Solver. Provedena je analiza osjetljivosti. Predložena su optimalna rjesenja.
Summary The theory of torsion of thin walled beams of open cross-sections with influence of shear... more Summary The theory of torsion of thin walled beams of open cross-sections with influence of shear on the basis of the classical Vlasov’s theory of thin-walled beams of open cross-sections for beams with single and double symmetrical cross-sections is developed. It is proved that the beam subjected to torsion with influence of shear exerted by couples in the beam crosssections is also subjected to bending due to shear in the plane orthogonal to the plane of symmetry. The beam is subjected to torsion with influence of shear only in the case of double symmetrical cross-sections. The principal cross-section axes as well as the principal pole are defined according to the classical theory of thin-walled beams of open sections. Illustrative examples are given, as well as a comparison with the finite element method.
This paper discusses the torsion and bending of a thin-walled girder of open cross-section, where... more This paper discusses the torsion and bending of a thin-walled girder of open cross-section, where the torsional stiffness is low compared to the warping stiffness. A computer program is given for the plane system of a thin-walled girder of open section. The modelling of plated structures by thin-walled girders of open section for ship's bottom structures is illustrated. The results were verified by finite element method, employing membrane elements.
A computer program with graphical user interface for the determination of the geometrical propert... more A computer program with graphical user interface for the determination of the geometrical properties of arbitrary thin-walled cross-section: open, closed-open and closed is presented. Both numerical and graphical outputs are enabled. The directions of corresponding shear flows are shown. The program calculates integrals for determination of shear factors as well. Obtained results are compared with those in published articles.
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