We analyzed the load and deformation in hollow beams made from multilayered glass-fiber-reinforced polymer, specifically assessing deformation under concentrated load. We performed nonlinear numerical analysis on beam with rectangular cross-sections with set dimensions and material properties. Beams with three different spans were analyzed, loaded with two concentrated forces at varying distances between applied force and supports. As the force was increased, we assessed the deformation near the supports. These results are shown in dimensionless diagrams, where the ratio of the applied and initial force correlates to the ratio of deformation near the support to deformation near the mid-span.

Sažetak: U radu je analiziran utjecaj ekscentriciteta kod rešetkastih nosača na unutarnje sile u štapovima. Analiza je provedena na konkretnom ravninskom rešetkastom nosaču s unaprijed odabranim dimenzijama nosača. Pretpostavka je da su štapovi ispune potpuno upeti u pojaseve kao i gravitacijski tip opterećenja. Usvojena je kombinacija zbroja vlastite težine i pokretnog opterećenja, koncentriranih u čvorovima gornjeg pojasa. Ekscentriciteti su zadavani u donjem pojasu, zatim gornjem pojasu te u oba pojasa. Vrijednosti ekscentriciteta su zadane kao omjer skraćenja štapa ispune i njegove duljine. Iz proračunom dobivenih rezultata, za kombinaciju opterećenja (stalno + promjenjivo), praćene su promjene vrijednosti momenta i uzdužnih sila na mjestima najvećih tlačnih sila, a to su: tlačni štap pojasa na sredini rešetke te tlačni štap ispune u prvom polju.Ključne riječi: rešetka, unutarnje sile, ekscentricitet, tlačni štap, pojas, ispuna THE INFLUENCE OF EXCENTRICITY ON INNER FORCES IN TRUSSESAbstract This paper analyses the influence of eccentricity on inner forces in the elements of a truss grider. A specific planar truss with predefined dimensions was analysed. It's assumed that web elements are equally rigidly connected to the chords and that the loads are gravitational. The load combination of self weight and one live load is used. Eccentricity is applied first in the lower chord, then in the upper chord and finally in both chords. Eccentricities are calculated as the ratio of the shortened length and the total length of the web element. From the results of the analysis, for the used load combination (self weight + live load) the changes in bending moments and axial forces were observed in the places of maximal compressive axial forces, that is the compressive top cord in the middle of the span and the compressive web element in the first field.

This paper presents an analysis of the deformations in hollow cross-sectional beams made of multilayer glass fiber-reinforced polymer at force application positions. A non-linear numerical analysis is conducted on a beam with a rectangular cross-section and familiar dimensions and material characteristics. Three beams with different spans that are all loaded with two concentrated forces are analyzed, where the distance of the forces from the supports is varied. The kneading deformations at the vicinity, where the two concentrated forces are applied, are monitored with regard to force increase. The results are shown in dimensionless diagrams, wherein the ratio of the actual and initial forces is related to the ratio of deformations at the force application points and mid-span.

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