By |October 31st, 2017|FEMAP, Linear FEA, Nonlinear FEA, RFEM, Stability, Steel Structures|

I got a really interesting question on my email from Fateme. I wanted to address this issue so many times now, so finally there is a great occasion to do this! In Abaqus, can we review the capability of a structural member? Whether or not it can bear the load like: shear, bending, twisting, axial [...]

## Structural rigidity: Moment of inertia

By |October 9th, 2017|Arf of Engineering, Q&A, Steel Structures|

I got a question from Manoj about the basics of rigidity. Since the post about structural rigidity (gummy bears!) is so popular I figured it would be nice to share another story about rigidity I often use... cavemen! The question may seem simple, but I'm sure there will be plenty cool ideas in this post [...]

## Buckling length in sway and non-sway structures

By |August 31st, 2017|Linear FEA, Stability, Steel Structures|

One of the few difficult things about buckling lengths is, that you need to know if your structure is a "sway" structure or a "non-sway" structure. Commonly the simple check is made with displacements, but unfortunately, it may lead to serious mistakes! Why should you care about sway and non-sway system Firstly, I want to [...]

## Buckling length basics

By |August 22nd, 2017|Linear FEA, RFEM, Stability, Steel Structures|

I'm preparing materials for another training about stability and I figured I have never written anything about frame stability on the blog! It's high time, so I decided to make a small roundup of methods on calculating buckling length in a frame system. Buckling length - do I need it? Let's start with the obvious: [...]

## Structural rigidity explained!

By |April 25th, 2017|Linear FEA, Stability, Steel Structures|

Structural rigidity is a very underrated concept I'm afraid. You see, usually, which part is more rigid than other does not directly influence the code-driven design methods. "Magic" happens when you do static design, and this process is far less regulated that dimensioning itself. I often meet engineers who completely do not understand this concept. [...]

## Materially nonlinear analysis – how does it work

By |April 3rd, 2017|Nonlinear FEA, Steel Structures|

When people think about nonlinear analysis usually what first comes to mind is material nonlinearity. This is the most “visible” aspect of nonlinearity in calculations. I won’t dare to say that materially nonlinear analysis is the most important one (I think that there is not such thing), but without a doubt, this is an important [...]

## Boundary conditions influence on static design – case study

By |March 20th, 2017|FEMAP, Linear FEA, Nonlinear FEA, Steel Structures|

Each day we do simplifications to boundary conditions just to reduce time spent on analysis. We are all aware, that structured support is crucial, but the actual influence of the proper boundary conditions is rarely examined. See yourself how drastic influence BC have on your design! I will discuss this using a project I just [...]

## Design your silos with FEA – it pays!

By |February 28th, 2017|FEMAP, Nonlinear FEA, Steel Structures|

Designing steel silos with analytical approach always yields very conservative results. Nonlinear Finite Element Method allow for great optimization of those structures (and other shell structures as well!). I will discuss this based on a silo I have recently designed. […]

## Connection rigidity: 5 things you need to know!

By |February 13th, 2017|Linear FEA, Nonlinear FEA, RFEM, Steel Structures|

Most engineers use a popular approach: connection is either a hinge or a rigid one. This is usually not the case. Just as with many other engineering problems in certain cases we simplify the reality by assuming perfect conditions (i.e. hinge). It is crucial to understand when such assumptions are incorrect, as this may lead [...]

## Connection rigidity: when it really matters?

By |December 20th, 2016|Nonlinear FEA, RFEM, Steel Structures|

Connection rigidity is important in many structural solutions. However taking it into account requires time, the time we usually don’t have. I share here my views on when connection rigidity is important, and when can it be ignored. […]

## Slippage in bolted connections

By |December 13th, 2016|Nonlinear FEA, RFEM, Steel Structures|

Slippage in connections is often neglected in the design of steel structures. I have seen its importance when I was working in the team investigating the structural failure. Just as easily I could learn about it when it was my design under investigation! It is incredible how easy it is to discard slippage from calculations, [...]

## Connection rigidity impact on static design

By |December 5th, 2016|Nonlinear FEA, RFEM, Steel Structures|

This is the third post about the rigidity of the connections in steel structures. Since we already have discussed what a hinge actually is, and how to calculate the connection rigidity, it is time to discuss how this all fits into the static design. It is also important to discuss the impact of connection rigidity [...]

## How to calculate connection rigidity

By |November 22nd, 2016|Nonlinear FEA, RFEM, Steel Structures|

In last post, we have learned how to check if the connection is a real hinge. Today we will treat our joint between steel members as semi-rigid and we will calculate connection rigidity. This is a very useful tool. It can be used to make an even more accurate design if necessary. If you ever [...]

## How to check if a connection is a hinge

By |November 8th, 2016|RFEM, Steel Structures|

In the first workshop for students in WrUT organized by Enterfea and Dlubal, a problem of rigidity of the connections in steel structures was presented and discussed. I had a pleasure to teach there with Ola Kociołek (CEO of Dlubal Poland). Have you ever wondered how to be sure that your connection is a hinge? [...]

## Nonlinear design of hopper for coal dust

By |August 14th, 2016|FEMAP, Nonlinear FEA, Steel Structures|

Today I will show you the nonlinear design process for coal dust hopper. This time tension will be the main issue (along with some bending), so structure won’t be susceptible to stability failure. In such cases, the approach to design is slightly different, as I point out in this post. […]

## Process of nonlinear design on example of polygonal shell column

By |July 17th, 2016|FEMAP, Nonlinear FEA, Steel Structures|

I have recently calculated a polygonal column for a book my friend writes. I have decided to use this real-life example to show how the process of numerical design looks like in practice. […]

## Critical bending moment: How to calculate it with numerical analysis (in RFEM)

By |May 29th, 2016|Linear FEA, RFEM, Steel Structures|

Lateral torsion buckling (LTB) is a very dangerous phenomenon, that can easily cause the collapse of a poorly designed beam. In civil engineering codes, the critical bending moment is crucial in the proper design of bent beams susceptible to LTB, as it allows for slenderness calculation.  In “typical” cases everything is ok since code equations [...]

## When to ignore contact in FEA?

By |July 4th, 2017|FEMAP, Linear FEA, Nonlinear FEA, Steel Structures|

Linear FEA calculations are the most common type of static analysis done with finite elements. So far we have discussed when it is safe to ignore material nonlinearity and when to ignore geometric nonlinearity. Ignoring those aspects allow you to use linear analysis which is a simple yet robust tool. There is another thing we should [...]