Did you know you can use Consteel to run second-order and buckling analyses on specific parts or elements of your model by defining a Custom Portion for the portion of interest?
The workflow starts in the Portions Manager, where you can manually group structural members, frames, columns, beams, bracings into Custom Portions. These are fully user-defined and, importantly, only these custom portions can be directly used for analysis. This allows you to isolate exactly the structural subsystem you want to investigate, without being constrained by the full model.
Once a portion is defined, it can be selected in the Analysis Settings, where you can choose whether second-order and buckling analyses should be performed on the entire model or only on the selected portion. The solver will then consider only that subset of elements when assembling the stiffness matrix and evaluating stability behavior.
Running these analyses on specific portions has clear engineering advantages. Second-order effects and buckling phenomena are often governed by local structural behavior, such as a critical frame, a bracing system, or a column group, rather than the entire structure. By isolating these regions, you can:
- reduce computational effort and analysis time, especially for large models
- focus on the most critical load paths and instability mechanisms
- perform faster iterations during design refinement
- avoid unnecessary influence from non-relevant parts of the structure
This targeted approach leads to more efficient and controlled stability analysis, particularly when investigating sensitive or highly utilized structural components.
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Try Consteel for freeDid you know that you could use Consteel to build 3D models with smart link elements which automatically adapt the model when profiles are changed?
Link elements are used to connect members that are not directly joined. In Consteel, three types of link elements are available: Link, Smart Link, and Constraints.
A smart link is a dynamic connection element designed to simplify the management of geometric changes between connected members. It automatically follows the movement, rotation, or profile changes of the primary member it is attached to, while also ensuring that any connected secondary member adapts accordingly.
A common application is connecting a main beam to a purlin or other secondary elements, with smart links positioned at specific points. They enable easy attachment of additional members while preserving the defined eccentricity, and automatically adapt to any changes in the main beam’s geometry or profile.
The Smart Link function, located on the Structural Members tab, opens the Edit Smart Link dialog box after activating the command. This allows you to:
- define the eccentricity of the link relative to the main section
- set the connection type in the Release field
The connection position can be specified manually or left to default automatically to the edge of the main member.
Defining the connecting section is optional. When specified, an eccentricity can be assigned, and the program automatically determines the link length based on the section height and reference point.
Smart links can be placed individually by clicking on a member or in groups by specifying distances from the member’s start. Any placement conflicts are indicated by a warning.
By combining associative behavior with precise control, Smart Links support efficient and reliable 3D modeling in Consteel. They help maintain structural intent throughout design changes, reduce manual corrections, and improve overall model consistency.
For workflows where geometry evolves and secondary members must remain accurately connected, Smart Links provide a clear advantage and enable a more resilient and adaptable modeling process.
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Try Consteel for freeDid you know that you could use Consteel to Consider the shear stiffness of a steel deck as stabilization for steel members?
In many practical steel structures, trapezoidal decking is treated only as a load-bearing surface. In reality, when properly connected to the supporting members, it behaves as a shear diaphragm and contributes to the overall stability of the structure. This effect can be directly taken into account in Consteel by applying shear field stiffness to beam elements.
The stabilizing effect comes from the in-plane shear stiffness of the deck. Under horizontal loading, the sheeting deforms and transfers forces between structural members. This behavior can be described by a single parameter, the shear stiffness (S), which represents the resistance of the diaphragm against deformation.
The overall stiffness is influenced by several components, including the shear deformation of the sheet, profile geometry, fastener slip, and connection flexibility. These contributions together define how effectively the deck can restrain phenomena such as lateral-torsional buckling.
A key requirement for this behavior is proper fastening. Typically, the sheeting must be connected along its edges and fixed to supporting members at each rib to ensure reliable diaphragm action.
In engineering practice, shear stiffness is determined using standardized or manufacturer-based methods rather than detailed analytical models. Consteel supports several established approaches:
- Schardt/Strehl method (DIN 18807), based on parameters describing shear and warping deformation
- Improved Schardt/Strehl method, including the effect of fastener spacing
- Bryan/Davies method, considering additional structural parameters
- Eurocode-based method, using general geometric properties of the sheeting
These methods differ in complexity and required input data, but all aim to provide a realistic stiffness value for use in global analysis. If the sheeting is not fixed at every rib, the calculated stiffness must be reduced accordingly.
The shear field object in Consteel allows engineers to include the diaphragm effect without detailed shell modeling. The calculated shear stiffness can be assigned directly to beam elements, providing additional lateral restraint.
The process involves selecting a trapezoidal sheet profile, choosing the appropriate calculation method, and defining the relevant geometric and connection parameters. The software then determines the stiffness and incorporates it into the structural model.
Including shear stiffness in the analysis can lead to higher critical load factors and reduced displacements, resulting in more efficient structural designs. However, it also means that the decking becomes part of the stabilizing system.
Any later modifications to the sheeting, such as openings or changes in fastening, may reduce this effect and should therefore be carefully assessed.
The shear stiffness of trapezoidal steel decking provides a measurable and often significant contribution to structural stability. By incorporating this effect in Consteel, engineers can achieve more realistic analysis results and optimize their designs while maintaining structural safety.
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Download modelIf you haven’t tried Consteel yet, request a trial for free!
Try Consteel for freeModeling stiffeners in Consteel
With Superbeam feature in Consteel, modelling of stiffeners is easy and effective. Multiple options and various shapes are available. Analysis is possible with beam and shell elements either.
gateIntroduction
Are you wondering how a web opening would influence the lateral-torsional buckling resistance of your beam? Check it precisely with a Consteel Superbeam based analysis
It is often required to let services pass through the web of beams. In such cases the common solution is to provide the required number of opening in the webplate. Such an opening can have a circular or rectangular shape, depending on the amount, size and shape of pipes or ventilation or cable trays.
Beams must be designed to have the required against lateral-torsional buckling. The design procedure defined in Eurocode 3 is based on the evaluation of the critical bending moment value which provides the slenderness value, needed to calculate the reduction factor used for the design verification.
There is no analytical formula provided in the code for beams with web openings. Would the neglection of such cutouts cause a miscalculated and unsafe estimation of the critical moment value?
The following demonstration will be made with a 6 meters long simple supported floor beam with a welded section.
Exposed to a linear load of 10 kN/m, the critical bending moment value of the solid web beam can be obtained by performing a Linear Buckling Analysis (LBA) with Consteel.
The obtained critical multiplier for the first buckling mode is 3.00 which means that the actually applied load intensity can be multiplied by 3.00 to reach the critical load level. The corresponding critical moment will have the value of Mcr = 3.0 * 47.18 = 141.54 kNm yielding a slenderness of 1.286 (Mpl,Rd = 234.20 kNm) and a lateral-torsional buckling resistance of 0.394 * 234.20 = 92.27 kNm. With this value the actual utilization ratio is at 51%.
How would this value change if a rectangular opening needs to be cut into the web of this beam?
Analytical formula for critical bending moment
By looking to the analytical formula (ENV 1993-1-1 F.4) to calculate the critical moment of double symmetric sections loaded at eccentric load application point it becomes obvious that the section properties having effect on the moment value are Iz, Iw and It.
An opening in the web has no effect on the first two values and has very little effect on the last one. As it has been already shown in previous article, the presence of such an opening can have effect on the vertical deflection, but as long as the lateral stiffness of a beam is much lower than it’s strong axis stiffness, the vertical deflections can be neglected when the lateral-torsional buckling resistance is calculated. The usual linear buckling analysis (LBA) performed also by Consteel neglects the pre-buckling deformations.
Therefore one can expect that in general web openings can be disregarded when the critical moment value is calculated.
Analysis with Consteel Superbeam
Beam finite elements cannot natively consider the presence of web openings. In order to obtain the precise analysis result, it is possible to use shell finite elements. The new Superbeam functionality comes as a solution in such cases. Instead of using beam finite elements, let’s use shell elements!
Opening can be positioned easily along the web, either as an individual opening or as a group of openings placed equidistantly. The opening can be rectangular, circular or even hexagonal. Circular openings can be completed with an additional circular ring stiffener.
The rectangular opening for this example can be easily defined with this tool. As there is no need to provide any additional opening on the remaining part of the beam, only the first part which includes the opening will be modelled with shell elements and the rest can still be modelled with beam finite elements. Using this technique, the total degrees of freedom of the model can be kept as low as possible. When using Superbeam, the designer has the choice whether to use beam or shell finite elements, as appropriate.
gateDefining cutouts with Superbeam feature in Consteel
Defining cutouts is a useful additional function within the Superbeam feature. They are easy to modify, various shapes and multi-placing option are available. Watch our feature preview for more details.
gateDual handling of members with Superbeam function in Consteel
Superbeam is a new function introduced with Consteel 15. It is developed for dual handling of members. Superbeam makes it possible to examine structural parts with the accuracy of shell elements but with the ease of using a beam element concerning definition, modification and model handling. We prepared a video to show how to convert a 7DOF beam into shell elements and how easy it is to work with it.
GateWeb openings and their deflection effect on beams
It is often required to let services pass through the web of beams. In such cases, the common solution is to provide the required number of openings in the web plate. Such an opening can have a circular or rectangular shape, depending on the amount, size and shape of pipes or ventilation or cable trays.
If the structural engineer has the freedom to position these openings along the beam, where to place them? What would be its effect on the deflection of the beam?
The effect of such openings on the deflection is more important when the length of the opening along the beam is increased. As circular openings are made with equal length and depth, they are usually less critical than rectangular openings.
The following demonstration will be made with a 6 meters long simple supported floor beam with a welded section.
Exposed to a linear load of 10 kN/m, the deflection at mid-span of the solid web beam is 4.6 mm.
Let’s assume that a 250 mm deep rectangular opening with a length of 400 mm needs to be provided on the web, at a distance of 300 mm from the left support.
Traditional analysis with beam finite elements
Consteel 7DOF beam finite elements are very powerful, but cannot consider natively such opening. The usual approach is to build a Vierendeel-type of model, by using additional beam elements with a T shape section „above” and „below” the opening. These additional beam elements are defined eccentrically to the reference line of the solid-web beam.
Eccentricities can be easily defined in Consteel using both smart and traditional link elements.
The deflection with this refined model will be equal to 4.8 mm.
Analysis with Consteel Superbeam – use shell elements for more precise analysis results
gateExample hall model for trying the smart link feautre in Consteel
Watch our user guide about How to use the smart link feature to learn more.
gateExample model for trying the smart link feature in Consteel
Watch our user guide about How to use the smart link feature to learn more.
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