ABSTRACT
In a complex structure, analysis is very often carried out by computer methods using small deflection elastic theory. In general, this results in many of the components of the structure being in axial compression. If these elements of the structure are slim, then there is a possibility of these components buckling at very small axial loads. Very often the axial stresses may be small, but because they are in compression, the structural components catastrophically fail by buckling or instability. If the component is long and slender, then it can fail elastically, but if it is short, it can fail inelastically and in these cases, the elastic theory has to be modified to cater for inelastic instability. Both elastic instability and inelastic instability are considered in this chapter.
