Strength of material 2 Essay Example | Topics and Well Written Essays - 500 words

Strength of material 2 - Essay Example Beams: Beams are often classified according to their ideal support conditions as either simply supported beams or cantilever beams. Beams are subject to bending stresses when loads are applied and experience compressive, shear and tensile forces. A simply supported beam is fixed on two ends. When loading the maximum tensile stress occurs at the midpoint of the bottom edge of the beam and the maximum compressive stress occurs at the midpoint of the top edge. A cantilever beam is supported on one end only and must be built into the wall that supports it. Two forces act on cantilever beams – firstly, a vertical upward force which supports the weight of the beam and any downward loads and secondly ‘the fixing moment’ which prevents the unsupported beam from falling (Eric William Nelson et all, 1997). A beam may be strong enough to resist bending moments set up by its load and yet may sag without collapsing. This is called deflection and is dictated by the elasticity a nd strength of the material used to build it. Columns and Struts: Columns, also known as stanchions support compressional loads along their longitudinal axes. The effective of excessive loading on a column is that the column could cause it buckle or crush like a wall coming down. A ‘short column’ is one whose height is small relative to its thickness is small relative to its thickness. Whether or not the column will remain stable under increasing axial load will depend on the strength of the material that constitutes the column. A ‘long’ or ‘slender’ column has a greater height relative to its thickness. A long column becomes unstable and buckles at a load much smaller than which would crush a short column of the same cross-section and material. This is called the ‘critical load’. Unlike beams, the loading capacity of a column depends less upon the strength of the material of which it is made than upon its stiffness and this decreases with a