The greater the depth of a beam the more load it can support

The greater the depth of a beam the more load it can support

ZIMSEC O Level Combined Science Notes: The relationship between a beam’s strength and depth

  • A beam is stronger if it’s depth if it has greater depth
  • For example if a plank is turned on its narrow side it is stronger than when it is lying in its wider side

Beams in nature and engineering

  • Where the load is applied in any direction such as in
  • Engineering structures
  • Biological structures such as the human body
  • In such cases a hollow cylindrical beam(tube)  is ideal
  • For example long bones, lamp posts, chair legs, building columns etc
  • In tubes the un-stretched material has been removed this makes them efficient and lighter
  • It would be difficult for animals such as humans to walk with solid beams
  • Tubes are equally strong in all directions including at right angles to the surface.
  • Square tubes are not as strong as tube beams in this regard.
  • A beam must be light and strong
  • Cylindrical beams achieve this by removing unstretched material
  • This increases their mass to strength ratio
  • A beam must also be thick in order to support extra weight
  • It must not be too long as this will result in it weakening the structure
  • beams in tall structure tend to be cylindrical
  • This is because tubes tend to crease rather than crack when placed under compression

Buckling

  • When cylindrical tubes are placed under pressure they are likely to buckle
  • Buckling occurs when the beam is not strong enough to resist shear forces
  • This can be prevented by making the beams thicker or by increasing their cylindrical diameter

To access more topics go to the Combined Science Notes page.


Quick NetOne, Econet, And Telecel Airtime Recharge