Paper Example. Axially Compressed High-Strength Stainless Steel Columns

Numerical study of the behavior and failure modes of axially compressed high-strength stainless steel column subjected to transverse Impact. The purpose of this study is to analyze, investigate, and evaluate the behavior and failure modes of axially compressed high-strength stainless steel columns that have been subjected to transverse impact. This paper will be divided into four sections. The first section will be the introductory section which will outline the scope, purpose, definition of terms, and background information regarding the paper. Background information regarding steel, stainless steel, stainless steel columns, axial compression, and transverse impact on axially compressed steel columns will be highlighted.
The second section will be concerned with a literature review. In this chapter, scholarly articles and books regarding the behavior failure modes of axially compressed high-strength stainless after subjection to transverse impact will be analyzed. The third section will try to answer the question of this study which is how axially compressed stainless steel behaves when subjected to transverse impact in different failure modes. The fourth section will explain and describe the findings in section three. In this section, the reasons for the behavior of axially compressed stainless steel subjected to transverse impact and the different failure modes will be highlighted. Steel

Is your time best spent reading someone else’s essay? Get a 100% original essay FROM A CERTIFIED WRITER!

Order now

Steel is an alloy of iron and a few percentage of carbon. A few percentage of carbon is added to iron to improve the strength of iron. However, other elements may be added. Stainless steels are steels that contain a minimum of 11% chromium and less than 1.2% of carbon (Cai 2014). Other alloying elements may be added. These alloying elements may include silicon and nickel.

Stainless Steel

Stainless steel is made by mixing these elements and melting them together in an electric furnace, an 8-10 hour process that involves a lot of heat. Stainless steel can be hardened using methods such as cold working to make it high strength depending on the needs.

A column which is also known as a pillar is a vertical structure in engineering that is used to support and transmit weight. A column transmits weight through compression, the weight of the structure and any object on the structure above, to the elements below. A column is usually made of iron or steel and concrete. Columns are made to be very strong because they support and transmit a lot of weight. Therefore, the materials making these columns must be very efficient and strong. Many columns that are used to support huge loads of weight are made of stainless steel. The stainless steel is usually very strong.

Applications of high-strength stainless steel columns

High-strength steel columns are used in tall buildings to support and transmit the weight of materials above including roofing. High-strength stainless steel columns are used to in the construction of bridges. These columns support huge weight of the materials made to construct the road and also the weight of the vehicles above. Specifically, high-strength stainless steel columns are used to support beams that lie horizontally above them in buildings they transmit the weight of these beams to the elements below them.

Numerical Modelling

Numerical modelling is used by civil engineers to evaluate objects such as rocks and how they may affect constructed structures. In this case, it is the evaluation of how objects like rocks may affect high strength steel columns and beams. Axial and transverse compression is brought about by a force. Objects such as rocks may produce these forces that may axially or transversely compress stainless steel columns and beams.

Axial compression on a column

This loads are applied to the ends of the member column to produce axial compressive stresses. The compression results in the transmission of the weight from the load downwards to the elements below. Axial compression in a column basically loading along the length of the column.

Transverse Impact

Transverse impact or loading happens when the load or force is applied perpendicular to the axial loading. The transverse loading makes a 90% angle with the axial loading on a beam or a column. This has the effect of causing perpendicular stressing or bending.

Types of stainless steel

Ferritic Stainless Steel – this type of stainless steel has very low composition of carbon. The carbon composition usually do not exceed 0.1%. This type of steel is mainly composed of the element Chromium. Because of this, they are very resistant to corrosion. They are therefore applied in industries like in the manufacture of cars. They are also used to make kitchenware because of the same property of resisting corrosion (Martins 2014)

Martensitic stainless steel – in terms of structure, this type of steel is the same as ferritic stainless steel. The difference between martensitic stainless steel and ferritic stainless steel comes in because of their carbon percentages. Martensitic stainless steels have a higher carbon percentage that is usually around 1%. Because of this higher percentage of carbon, these stainless steels can be hardened further and hence they can be made stronger. Because they also have a high percentage of chromium, they can be strong and also be averagely resistant to corrosion. They are therefore applied in making materials that require these specifications such as water pumps.

Austenitic stainless steel – this is the most common type of steel. It has a very high composition of the element nickel. It also generally has high composition of other elements such chromium and molybdenum. Because of this, it possesses good characteristics of being both strong and also being highly resistant to corrosion. It also possesses qualities like malleability which is the ability to be formed into sheets without breaking. Austenitic stainless steel therefore has a lot of applications. However, because of this qualities, it is very expensive.

Duplex stainless steel – this type of steel is a combination of both ferritic and austenitic stainless steels. It has a less composition of nickel. It is mostly applied in under water oil industries because of the property of resisting corrosion as a result of salt water.

Categories of failure modes in steel

Failure modes in steel are a result of corrosion and other types of mechanical damage. Mostly, it is due to corrosion. The person who examines what causes a metal to fail is called a metallurgist. Failure modes in steel can be manifested in the following ways:

Mechanical overload. This type of failure happens as a result of a weight or a load that outstretches the limit of the steel. This could be as a result of the weight being excess or going beyond the limit, or the stainless steel being weaker than expected (Cai 2014)

Fatigue – This is the weakening of a structure especially those supported by metal such as steel, which happens progressively in a cycle. Typically, in concrete structure supported by weak or failing steel, a crack happens that grows in with time until the steel and structure generally reaches maximum weakness.

Hydrogen embrittlement – this is generally the cracking in a metal in this case steel that is induced by hydrogen. When a steel is subjected to stress and hydrogen, it may crack.

Creep- This type o failure is the behavior of a metal slowly as result of stress. This stress may be below the strength capability of the metal but may be making the metal to move slowly. Over time, this slow movement could be significant. Corrosive fatigue – this is the weakening of steel in the form the cyclic fatigue but in this case, the metal being in a corrosive environment. The rate of mechanical failure of the steel is higher because of presence of a material to induce stress and being in a corrosive environment.

Types of failure modes in high-strength stainless steel

Plastic Global Failure – plasticity is a common mechanism that is evident in high strength stainless steel. Excessive plasticity especially in austenitic stainless steel cause the general failure of the steel when the plasticity collapses.

Tensile tearing failure- tensile strength is the capability of a material to withstand the force of pulling away or being stretched. Tensile tearing failure in high-strength stainless steel is the incapability of high strength stainless steel to withstand this kind of force.

Transverse shear failure – this is the inability of high strength stainless steels to develop resistance to materials or loads that act on them perpendicularly or transversely. Shear failure causes the appearance of cracks in structures. The onset of shear failure can therefore be determined by observing the appearance of cracks in structures like columns or beams that are made of high strength stainless steels.

Plastic buckling- buckling is the behavior of a material to bend and give away when a critical force is applied to it. High-strength structures such as columns or beams may buckle when a constant critical force or load is applied. This happens when this applied load or weight is beyond the limit of the structure and of course the high-strength stainless steel adding strength to the structure.

In addition, to these failure modes, high-strength stainless steel may fail due to the factors mentioned for steel above. High strength stainless steel is applied in structures that are very critical such as making beams and columns in tall and big buildings and also in bridges. Any failure that may occur in these stainless steels as mentioned above may be very costly in terms such as the destruction of a lot of money and may be loss of lives.

In buildings generally, beams are used to support slabs that support weight on materials that lie or will lie on top of the slabs. These concrete slabs are made by adding concrete mixture to stainless steels. The purpose of these steels is support the weight. Columns on the hand support these beams and hence the slabs. They are vertical structures that make a 90-degree angle with the ground below them. They are made of high-strength stainless steel with a concrete mixture added to them. They therefore support and transmit a lot of weight downwards. In bridges, columns supports a lot of load and weight that is exerted by the materials that make the roads above them. Vehicles and accidents especially make exert a lot of weight. The stainless steels that make these column members must therefore be very strong to be able to handle and transmit the weight.

As illustrated in the four pictures above, axial compression and impact loading are certain kinds of forces that causes high strength stainless steel columns to behave in a certain way. These reactions as a result of these types of impacts may cause failure in these structures. Axially compressed columns are columns that are subjected to some force above them. This force acts directly on top of them. The columns then support and transmit the weight downwards along the axis of the column.