Kritiska vippningslaster för kompositbalkar/lättbalkar av trä

Sammanfattning: This thesis has focused on the calculation of critical loads for lateral torsional buckling forthree selected wood-based composite beams with varying heights based on the availableMasonite Beams standard range. The main objective has been to investigate and compare ahand calculation model with the recommended method in Eurocode 5, as well as comparethem with results from finite element analysis.In this study, two instability phenomena have been addressed, namely lateral torsionalbuckling and flexural column buckling. The reason for addressing flexural columnbuckling is that the Eurocode method is based on a simplified flexural column bucklingmodel to facilitate the calculation of the moment carrying capacity regarding lateraltorsional buckling for I-beams subjected to bending.The hand calculation model used in this study is based on classical stability theory. Itis applied to a cross-section that differs moderately from the actual cross-section, whichin turn underestimates the load-bearing capacity. As lightweight beams are composed oftwo different wood-based materials, the cross-section has been transformed to a fictitiouscross-section to facilitate the hand calculation. In the pursuit of more realistic results, afinite element model has been established, and two analyses based on this model havebeen performed.The beams are assumed to be supported at the ends under forked conditions, which meansthat they are free to deflect vertically and laterally but the rotation about the beam axis isfixed. They have been examined for three load cases, namely constant bending moment,point load at the midpoint, and uniformly distributed load.By comparing the results obtained from the hand calculation and the Eurocode method,this study concludes that the Eurocode method significantly underestimates the momentcapacity and is applicable to braced beams. However, the hand calculation overestimatesthe moment capacity, as evident