Lateral-torsional and lateral-distortional buckling of I-section members with web openings
The use of beams with large circular web openings has increased steadily during the last decade. However, not all aspects of the design of cellular beams have been studied extensively, such as lateral-torsional buckling, a general buckling mode of the beam. Currently, two approaches exist for calculating the critical lateral-torsional buckling moment of cellular beams, but these are not very accurate and there is a need for a new design rule. In order to demonstrate this need we have done numerical simulations in Abaqus for a number of geometries, of which this paper summarizes the most important results. The first approach for calculating the critical moment is accurate for some cases, but, due to web distortion, very unsafe for other cases. The second approach is overly conservative. To formulate a design rule in the future, more research will be needed.
This study was focussed on the effects of changes in interocclusal clearance on the activity of oral muscles. Two types of occlusal splints were incorporated in 20 subjects without TMJ-syndrome. Their muscle reactions were recorded electromyographically in the masseter muscle. The results show 5 groups of muscle reaction correlated with the mean postural face height. The changed height of the postural position has a significant influence on the control pattern of the masticatory system.