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Beams are used all around us in many mechanical and structural engineering applications. They are commonly used to create a foundation or internal support for a larger structure, such as a building or a bridge. Beam analysis is a technique used to adequately design beams to withstand forces and stress while minimizing beam weight, space requirements, and material cost. Incorrectly designed beams can prematurely fail and have catastrophic effects.
Beam analysis requires a combination of mechanical engineering, design principles, and material properties. The process typically involves factors including the types of forces that will be applied, the span between supports, the beam shape, the material, and the design of the joints to allow one beam to be mechanically connected to other structural members. Different types of beam designs are based on the loading and mounting configurations. For example, cantilevered beams are supported at one end only and require a different design than simple beams, which are supported at both ends.
Beams can be constructed using a single material, such as carbon steel. They can also be constructed as a composite or laminated structure consisting of varying numbers of different layers of materials. The construction of a beam will influence its bending and deflection while under load. The deflection of a beam depends on its length, how it is supported, its cross-sectional shape, the material, and where the deflecting force is applied. Beam analysis will determine the amount of bending and deflection.
Until recently, manual methods using force diagrams and a series of complex mathematical equations were necessary for beam analysis. Today, this procedure is usually completed using engineering software that is designed to accept input data and determine a beam design to meet the performance criteria. These programs complete a mathematical analysis of the beam stresses and deflection, and also create diagrams showing stress distributions within the beam under various loading conditions. Beam analysis software uses a computational method known as Finite Element Analysis (FEA).
An important consideration in beam analysis is the margin of safety or safety factor. Most beams have a safety factor that serves to oversize the beam in the event of loading or other factors that cannot be predicted in the design of the beam. An excessive safety factor will drive a beam design that is larger than necessary, causing possible weight problems and higher fabrication costs. Beam analysis software can analyze different beam shapes and materials, to allow the user to assess options and select a final beam design that optimizes the ratio between cost and functionality.