Oluschinski: Created page with "{{Language_sel|LANG=ger|ARTIKEL=Bruch}} {{PSM_Infobox}} Fracture FORCETOC ==The fracture of plastics== Fracture is the most dangerous cause of failure on the material side. The term "fracture" refers to the macroscopic separation of the material leading to the loss of the load-bearing capacity of the body. In the case of plastics, material separation occurs through the brea..."

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Created page with "{{Language_sel|LANG=ger|ARTIKEL=Bruch}} {{PSM_Infobox}} <span style="font-size:1.2em;font-weight:bold;">Fracture</span> __FORCETOC__ ==The fracture of plastics== Fracture is the most dangerous cause of failure on the material side. The term "fracture" refers to the macroscopic separation of the material leading to the loss of the load-bearing capacity of the body. In the case of plastics, material separation occurs through the brea..."

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{{Language_sel|LANG=ger|ARTIKEL=Bruch}}
{{PSM_Infobox}}
<span style="font-size:1.2em;font-weight:bold;">Fracture</span>
__FORCETOC__

==The fracture of plastics==

Fracture is the most dangerous cause of failure on the [[Material & Werkstoff|material]] side. The term "fracture" refers to the macroscopic separation of the material leading to the loss of the load-bearing capacity of the body. In the case of [[Plastics|plastics]], material separation occurs through the breakage of molecular chains, the pulling out of molecular chains and the tearing open of [[Phase Boundary Surface|phase boundary surfaces]]. Furthermore, [[Micromechanics & Nanomechanics|crazes]] and shear bands can occur as local plastic deformations or spherulitic boundaries (see: [[Spherulitic Structure|spherulitic structure]]) can be torn open. These localised plastic deformations can be detected using scanning electron microscopy methods (see: [[Scanning Electron Microscopy|scanning electron microscopy]]).

The physical cause of a fracture is that the atomic or molecular bonds are destroyed as a result of external and/or internal mechanical [[Stress|stresses]], in some cases with the involvement of surrounding media, [[Velocity|speed]] and, in particular, temperature, resulting in a free surface ([[Fracture Surface|fracture surface]]).

==The real fracture strength==

For each material, there is a theoretical fracture strength (cohesive strength) dependent on the bonding forces, which can be estimated using [[HOOKE's Law | HOOKE's law]] and the [[Surface Energy | surface energy]]. However, the real fracture strength is several orders of magnitude lower. The reason for this is the concentration of stress on a few atomic bonds at the tip of [[Crack | cracks]] or crack-like material inhomogeneities.

Crack initiation and [[Crack Propagation | crack propagation]] processes precede fracture. The type of crack propagation determines the characterisation of the fracture. While stable crack propagation often leads to a macroscopic toughened fracture, unstable crack propagation leads to macroscopic brittle fractures.

Tough fractures are associated with the occurrence of micromechanical deformation mechanisms such as crazing or shear yielding. Macroscopically, a plastic deformation of the moulded part or [[Component Testing | component]] is often visible. In contrast, brittle fractures are low-deformation fractures.

==See also==

* [[Fracture Types | Fracture types]]
* [[Fracture Mechanical Testing | Fracture mechanical testing]]
* [[Fracture Surface | Fracture surface]]
* [[Fracture Behaviour | Fracture behaviour]]
* [[Fracture Behaviour of Plastics Components | Fracture behaviour of plastics components]]

'''References'''

* [[Blumenauer, Horst|Blumenauer, H.]], Pusch, G.: Technische Bruchmechanik. Deutscher Verlag für Grundstoffindustrie, Leipzig (1993) 3rd Edition, p. 15, (ISBN 3-342-00659-5; see [[AMK-Büchersammlung | AMK-Library]] under E 29-3)

[[Category:Fracture Mechanics]]
[[Category:Damage Analysis_Component Failure]]

Fracture - Revision history