Finite Element Analysis In Structural Engineering

 1. Finite Element Analysis in Structural engineering 

 Everything we see around us, from roads, bridges, dams, sewerage and pipeline systems, to buildings, railways, and airports, falls under the structural engineering umbrella. Structures built all across the world have become increasingly complicated throughout time, as have the tools for analysing their performance. Today, FEA is one of the most essential approaches. In the subject of structural engineering, the term "finite element analysis" (FEA) is a buzzword. It's a very valuable tool for numerical approximation of complex physical structures that can't be examined using normal mathematical answers, like Slope Deflection, Work Energy Principle, and so on. To put it another way, "unsolvable" engineering issues are addressed with high precision.

2. When is FEA used? 

You might be wondering what those "unsolvable" physical structures are. Consider two identical wooden beams, which are both constructed of the same material and have the same features. Their only difference is their geographical location. The first beam is in a relatively theoretical position, with both ends supported and only the central span weighted. The deflection of the centre span may be simply computed, hence this scenario would be considered easy. On the other hand, with the second beam, we want to cross a narrow stream. This relatively straightforward task is now, in practical application, an engineering nightmare, as there are literally dozens of more or less possible situations that could go about — from our wooden beam breaking under excessive load or sliding at any end from the riverbank, to withstanding years of temperature oscillations, wind, and rain.

3. Where is FEA used in structural engineering? 

Typical areas FEA deals with include fields such as structural analysis, heat transfer, mass transport, electromagnetic potential, and many others. These are all important to encompass when designing and planning any object, as engineers are required to determine the structure’s behavior in diverse situations, more or less predictable. The object’s performance when subjected to loads, gravity, wind, temperature oscillations, and even natural disasters such as earthquakes or tsunamis, is 5 analyzed, in order to determine whether the structure will break, wear out, or somehow else be damaged, or will it work as it should. Generally, solutions such as unit load and moment distribution method, as well as strain energy formula, are employed in determining the behavior of simpler structures (supported beams, trusses). However, non-standard objects require an in-depth analysis, using structural codes. These codes allow a more reliable and less costly testing, compared to laboratory experiments, and provide a set of acceptable behaviors of structures during earthquakes and high wind loads. One of the major structural engineering concerns are earthquakes, and in general, all sorts of natural disasters, both because a large number of buildings are not constructed up to standards, and because the characteristics of such catastrophes are not easily and accurately predictable. 

4. FEA Applications in Buildings: 

Whether you are building a simple residential building or the next Burj Khalifa, understanding the structural behavior and integrity of your building is extremely important to ensure the safety of its occupants. 

Structural analysis involves determining the behavior of a structure when it is subjected to loads, such as those resulting from gravity, wind, or even in extreme cases natural disasters (e.g., earthquakes). Using basic concepts of applied mathematics, any built structure can be analyzed—buildings, bridges, dams or even foundations. For example, in the right conditions, a structure such as the Burj Khalifa would oscillate by up to 3m at its highest point. Imagine living on the top floor and 7 being subjected to this kind of motion. For more reasons than one (nauseated inhabitants included), this kind of motion needs to be controlled, and most structures use a damper to reduce the motion. Taipei 101 has a famous tuned mass damper.
To be precise, Burj Khalifa has no damping system like a tuned mass damper or so. The structural integrity of the building itself is the damping system and it confuses winds. 

However, in contrast to Taipei 101, rather than take valuable space with a damper, the team of architects and engineers responsible for the Burj Khalifa instead specifically designed its shape to “confuse” winds, and therefore reduce oscillation from wind loads. 

Originally, civil engineers used laboratory experiments to solve these design problems, especially in regards to the behavior of the steel structures when subjected to high wind loads and earthquakes. However, such reliance on laboratory testing was costly and not immediately accessible. Thus, structural codes were developed. These codes made it easier for engineers to define what sort of behavior was acceptable and safe for standard structures. However, with the recent advent of accessible CAE tools, designing, testing and guaranteeing the safety of an innovative building project and its materials has become easier, faster, and significantly cheaper.

4.1. Innovative Building Materials 

Concrete has been a building material for a very long time. There are many phenomena like alkali-silica reactions where research continues. Why does concrete crack and how does the composition influence the crack growth? Can we create self-healing materials? 9 One of the biggest ifs in an FEA simulation is the accurate determination of material properties. This is where novel research areas like multiscale modeling come into the picture. Using a multiscale model, one is able to use the microstructure (or otherwise each individual component property) to determine the property of the concrete (or otherwise the property of the whole).

4.2. Sedimentation, Erosion & Hydrology 

The motion of water produced in coastal areas is more predominant than inland waterways. Generation of high current waves, tides, ocean currents, storm surges, tsunamis, wind currents, etc. bring complications, and along with water particles cause subsequent damage and destruction of marine structures. In the context of coastal flow problems, the boundary conditions of reflection and diffraction of wave-current complicate the civil engineers to analyze the same to get the solutions. Thus, coastal flow modeling (finite element modeling of fluid flows) and analysis based on numerical-empirical methodology is of today’s trend. It is not just the coastal areas but also the catchment regions where hydrological models have been used over the last decades to understand the flow of water in porous soil and thus contributing to the groundwater levels. 

5. Benefits Of FEA In Structural Engineering 

 5.1. Improved Accuracy 

Past structural design processes started by sketching, which were followed by prototype development and the manufacture of the designed structures. In such cases, the testing phase sometimes reveals that some parameters are overlooked and this leads to the failure of some structures. Such challenges are overcome through the use of F.E.A. F.E.A. requires the designers to input all the material parameters. The inclusion of all parameters enables precise modeling of all physical stresses on each structural unit. This use of F.E.A. increases material accuracy in the design of structural components by showing how all stresses may impact on the design of a structure. 

5.2. Affordable and Faster Design Cycle 

In the use of F.E.A., most design iterations don’t depend on manufacturing and machine shop schedules. Almost all new designed structural components can be tested in a few hours. As such, you don’t have to wait for weeks or days for a hard copy to get the tests done.

5.3. Improved Design 

F.E.A. allows the designer of a structure to model a whole structural system instead of separate structural components. The modeling is helpful in improving the speed of product development. The use of different types of finite element analysis allows the designer of a structure to determine how the stress components in one part of the structure will impact the other materials and components in another separate piece of the structure. 11 

5.4. Insights Into Crucial Design Parameters 

The use of different types of finite element analysis allows you to model the exteriors and interiors of any designed structure. Finding out how critical design factors affect the entire inside and outside of a structure is of great advantage to a designer. A designer needs to understand where failures may occur and why they will occur. 

5.5. Virtual Prototyping 

F.E.A. simulations assist in reducing many iterations of the initial metal prototyping phase. The prototypes are costly because they take a lot of time and labor to build by hand. Unlike hard prototyping that may take weeks, as a designer you can use F.E.A. software to simulate the structural system you intend to build. You can also model the structure in different materials and designs within hours. 

5.6. Few hardware Prototypes 

The high-quality simulations in F.E.A. software allow structural designers to start virtual testing early in the design process. The ease of using simulations reduces the designer’s reliance on many physical prototypes and thus cutting prototyping costs. This outcome implies you can cut material wastage and shorten the design cycle. Many structures are either failing or at a point where they pose significant safety concerns. For instance, over 25% of bridges in the U.S. are handling more traffic than their design specifications or they need considerable repair work. Redesigning and prototyping such structures may take lots of time and resources if done in the physical form. It’s thus ideal for structural engineers in these areas to seek different types of finite element analysis simulations to find remedial measures that will improve the functionality of such structures