Joining parts of a plane. Image credit

Joining parts of a plane. Image credit

ZIMSEC O Level Combined Science Notes:Methods of Joining materials

  • Building structures such as bridges and pylons using solid material would be needlessly expensive
  • Most of this material would be in a neutral zone where it will not be subjected to any stress
  • This means that it can be eliminated by using trusses without affecting the strength of the structure
  • Since trusses and other pieces used in making structures do not conform to the shape/size of the structure
  • It is necessary to join various pieces of trusses together
  • Another reason for joining materials is to extend their length
  • For example railway lines often extend for hundreds and even thousands of kilometers
  • It would be impossible to create such a railway line without joining materials
  • Regardless of why they exist
  • Joins can and are often a source of weakness for structures
  • This is especially important in structures such as ships, bridges, planes, cranes etc
  • Where the joints are subjected to a lot of extremely high stresses
  • As a result very strong and efficient joints are needed
  • To prevent the structures from failing and creating costly and often fatal problems
  • In items like furniture, doors, floors and stair cases
  • Joints often come with certain advantages
  • They allow for an even distribution of load
  • They can also provide room for material to shrink and expand
  • These structures also “give”
  • For example a chair/sofa gives in when you sit on it
  • This allows the structure to spread out load
  • In some structures using rigid materials will increase their strength
  • Rigid material are not easily deformed/bend out of shape when forces are applied to them
  • There are various types of joints each with its own advantages and disadvantages

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

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