Engineering Unit: Grade 9 science IB Flashcards
What is a Mechanical Property?
A mechanical property determines how a material will react when it is subjected to one or more mechanical constraints.
List the types of Mechanical Properties:
- Hardness (resists penetration)
- Elasticity (returns to original shape)
- Resilience (resists physical impacts)
- Ductility (stretches without breaking)
- Malleability (flattens or bends without breaking)
- Tensile strength (resists tension, elastic)
What is a mechanical constraint?
A mechanical constraint describes the stress produced within a material when it is subjected to one or more external forces; mechanical constraints produce various effects inside a material.
List the 5 principle mechanical constraints:
- Compression (crushes materials)
- Tension (force that stretches materials)
- Torsion (force that twists materials)
- Bending (force that bends materials)
- Shearing (force that cuts/tears materials)
What are the 4 mechanical functions?
- Link
- Guide
- Lubrication
- Seal
Define a link:
Links are used to connect 2 or more parts of an object.
Define a guide:
Forces a part to follow a certain guiding motion (translation/rotation)
Definition of lubrication:
Reduces friction by technical means.
Definition of seal:
Prevents a gas or liquid from escaping.
Types of guiding:
Rotations, Translation, Helical
Gear Train:
- Components of a gear train include and driver, and a follower, sometimes they also include intermediates.
- In a gear train each gear turns opposite in direction to the gear(s) directly beside it
- Reversible
- Motion Transmission system: rotation - rotation
- Should be lubricated
Chain and Sprocket systems:
- Components of a chain and sprocket system include gears, and a chain .
- In a chain and sprocket system gears within the train turn one way, and gears outsides the chain turn the opposite direction.
- Reversible
- Motion Transmission system: rotation - rotation
- Should be lubricated
Chain and Sprocket systems:
- Components of a chain and sprocket system include gears, and a chain .
- In a chain and sprocket system gears within the train turn one way, and gears outsides the chain turn the opposite direction.
- Reversible
- Motion Transmission system: rotation - rotation
- Should be lubricated
Friction gear system
- Components of a friction gear system include and driver, and a follower, sometimes they also include intermediates.
- In a friction gear system each gear turns opposite in direction to the gear(s) directly beside it
- Reversible
- Motion Transmission system: rotation - rotation
- Should NOT be lubricated
- Diameter = teeth (equivalent to gear train)
Belt and Pulley system
- Components of a belt and pulley system include pulleys (gears without teeth), and a belt.
- In a belt and pulley system pulleys within the belt turn one way, and pulleys outsides the belt turn the opposite direction.
- Reversible
- Motion Transmission a system: rotation - rotation
- Should NOT be lubricated