The AXISVM program is suitable for designing steel structures. For this the SD1 module provides a versatile support. This article discusses the basics of the module.
Definition of the design parameters #
The design of steel beams is based on “construction elements”, that can be composed of multiple beams and are created by defining the design parameters.
- Rolled I profiles (e.g. HEA, HEB)
- Single symmetric I-profile (welded/rolled)
- Closed rectangular profiles (e.g. RHS)
- Pipe profiles (e.g. ROR)
- T profiles
- Circular and rectangular solid profiles
The design of other cross-sections is possible. For certain cross-section types not all checks can be performed. The manual’s 6. “Results” part’s chapter 6.6.2 contains a table of all available checks for the individual cross-section types.
Design approach and section class #
The design approach specifies the method to calculate the resistances.
- By section class (elastic/plastic) – both resistance calculations are allowed, the method used is determined by the cross-section class
- Elastic design – all resistances are determined by the elastic cross-section values
The calculation of resistances for cross-section class 4 is based on effective (reduced) cross-section values.
The cross-section class determines the allowed methods for the calculation of cross-section resistances. The grading is cross-section classes is based on the slenderness criteria for cross-section parts under compression from the selected design code. For this classification, the type of load is taken into account (pure pressure, pure bending, bending with normal force).
Possible classes and features:
Section class 1 – plastic cross-section resistance
Section class 2 – plastic cross-section resistance
Section class 3 – elastic cross-section resistance
Section class 4 – elastic cross-section resistance, based on a reduced cross-section
Design member #
It is adjustable that the actual design member is braced or not. If it is not, than this option could be turned off and the design member is going to have a sway frame buckling mode.
This is optionable in planes x-y and x-z and has an impact on many calculation parameters. These settings affect the automatic flexural buckling calculation, and in case of lateral torsional buckling the lateral supports. Furthermore, they affect moment factors in the stability interaction check.
One design member can involve more beams in its entire length and they can be handled as one element from design approach. For this the following options available:
One design member per section between two adjacent beams or supports.
One design member on the entire length of the selected chain of beams.
Stability parameters #
With the settings of stability analysis and it’s parameters there are relating articles which are detailed enough. As a short overview here are the main types of calculation and options available in AXISVM:
- Buckling – either in y or in z directions the buckling length can be defined in different ways
- Buckling factors – it is a coefficient which can take into account the support conditions
- Buckling length – here the buckling length itself can be given
- Automatic – in this option the program automatically detects and sets the buckling length
- In the first two cases the apllied buckling curves can be set or to consider it by automatically, or the geometrical nonlinearity + imperfections should be considered
- Lateral-torsional buckling – here it is also several options to choose, the main difference between these methods is the way to consider the elastic critical moment
- Auto Mcr
- C1 Lopez formula
- Custom C1, C2, C3
- User defined – a direct Mcr value given by the user
- The parameters must be set carefully, the user decides to take into account the effect of restrained warping or not (only in case of 7 dof beam)
- Lateral-torsional buckling curves also can be set manually or automatically
- Web shear buckling – this stability check can also be done, with the following options:
- No stiffeners
- Transversal stiffeners
Source of information http://www.ingware.com
