What does the Charpy impact test tell us?
The Charpy impact test is performed to evaluate the resistance of plastics to breakage by flexural shock according to standard test method ASTM D6110 . It indicates the amount of energy needed to break standard test specimens under specific conditions of specimen, mounting, notching and pendulum velocity at impact.
How do you calculate Charpy impact value?
- The Knotch Impact Energy KV = mgH – mgh.
- m – Mass of the Pendulum.
- H – Height of Pendulum starting point.
- g – Gravity.
- h – Height of the pendulum from the first reversal point.
What is the result of impact test?
The qualitative results of the impact test can be used to determine the ductility of a material. If the material breaks on a flat plane, the fracture was brittle, and if the material breaks with jagged edges or shear lips, then the fracture was ductile.
What is a high fracture toughness?
Fracture toughness is a quantitative way of expressing a material’s resistance to brittle fracture when a crack is present. If a material has high fracture toughness, it is more prone to ductile fracture. Brittle fracture is characteristic of materials with less fracture toughness.
How is impact toughness measured?
The impact toughness of a metal is determined by measuring the energy absorbed in the fracture of the specimen. This is simply obtained by noting the height at which the pendulum is released and the height to which the pendulum swings after it has struck the specimen .
How do you interpret impact strength?
Impact strength is calculated by dividing impact energy in J by the area under the notch. The test result is typically the average of 10 specimens. The higher the resulting numbers the tougher the material.
What is good impact resistance?
High-density polyethylene (HDPE) HDPE is a durable, versatile thermoplastic that offers fantastic impact resistance and tensile strength. Since its molecules are packed together so tightly, HDPE boasts incredible toughness and rigidity. HDPE is also resistant to chemicals, corrosion, absorption, and abrasion.
What is cleavage failure?
Cleavage fracture is a fracture, usually of polycrystalline metal, in which most of the grains have failed by cleavage, resulting in bright, reflective facets. It is a type of crystalline fracture and is associated with low-energy brittle fracture. It exhibits a river pattern when examined under an electron microscope.