Tài liệu tham khảo giáo trình nhôm trong thiết kế xây dựng bằng tiếng anh - Chương 7 Plate elements in compression GENERAL DESCRIPTION Local buckling In aluminium design it is often economic to employ wide thin sections, so as to obtain optimum section properties for a minimum weight of metal. The extrusion process makes this possible. The limit to which a designer may thus go in spreading out the material depends on local buckling of the individual plate elements comprising the section. If the section is made too wide and thin, premature failure will occur with local buckles. | CHAPTER 7 Plate elements in compression GENERAL DESCRIPTION Local buckling In aluminium design it is often economic to employ wide thin sections so as to obtain optimum section properties for a minimum weight of metal. The extrusion process makes this possible. The limit to which a designer may thus go in spreading out the material depends on local buckling of the individual plate elements comprising the section. If the section is made too wide and thin premature failure will occur with local buckles forming in elements that carry compressive stress Figure . The first step in checking the static strength of a member is to classify the cross-section. Is it compact or slender If it is compact local buckling is not a problem and may be ignored. If it is slender the resistance will be reduced with interaction occurring between local buckling of individual plate elements and overall buckling of the member as a whole. Types of plate element Two basic kinds of element are recognized namely internal elements and outstands. An internal element is attached to the rest of the section at both Figure Local buckling. Copyright 1999 by Taylor Francis Group. All Rights Reserved. Figure Basic element types internal left and outstand right . its longitudinal edges an outstand at only one Figure . In some lightgauge steel codes these have been confusingly referred to as restrained and unrestrained elements. An element may be subjected to uniform compression see Section as when it forms part of a compression member or of a horizontal compression flange in a beam. Or it may be under strain gradient as in a beam web see Section . Elements are usually in the form of a plain flat plate. However it sometimes pays to improve their stability by adding a stiffener in which case they are referred to as reinforced or stiffened elements see Section . Plate slenderness parameter The ability of an element to resist local buckling depends on the .
