The concept of slenderness ratio λ = μ 1/i, i being the radius of gyration, can be seen simply from the formula: slenderness ratio is the ratio of the calculated length of the member to its corresponding radius of gyration.From this formula, it can be seen that the concept of length/finish ratio takes into account the end constraints of the member, the length of the member itself and the cross-section characteristics of the member.The influence of the concept of slenderness ratio on the stability calculation of compression bars is obvious, because the larger the slenderness ratio, the more likely the member to be unstable.You can look at the formulae for axial compression and compression bending members, which contain parameters related to slenderness ratio.For tensile members, the code also gives a limit of slenderness ratio, which is to ensure the stiffness of the member in the state of transport and installation.The higher the stability requirement, the smaller the stability limit given by the code.