Oluschinski: Created page with "{{Language_sel|LANG=ger|ARTIKEL=Faserorientierung}} {{PSM_Infobox}} '''Fibre orientation; Glass fibre orientation''' FORCETOC ==Orientation of reinforcement fibres== Fibre orientation refers to the alignment of reinforcing fibres in the matrix. Fibres are used in many engineering plastics to increase the strength and stiffness (see also: Tens..."

2026-09-03T12:18:13Z

Created page with "{{Language_sel|LANG=ger|ARTIKEL=Faserorientierung}} {{PSM_Infobox}} <span style="font-size:1.2em;font-weight:bold;">'''Fibre orientation; Glass fibre orientation'''</span> __FORCETOC__ ==Orientation of reinforcement fibres== Fibre orientation refers to the alignment of reinforcing fibres in the matrix. Fibres are used in many engineering plastics to increase the strength and stiffness (see also: Tens..."

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{{Language_sel|LANG=ger|ARTIKEL=Faserorientierung}}
{{PSM_Infobox}}
<span style="font-size:1.2em;font-weight:bold;">'''Fibre orientation; [[Glass Fibre Orientation|Glass fibre orientation]]'''</span>
__FORCETOC__

==Orientation of reinforcement fibres==

Fibre orientation refers to the alignment of reinforcing fibres in the matrix. Fibres are used in many engineering [[Plastics|plastics]] to increase the [[strength|strength]] and [[Stiffness|stiffness]] (see also: [[Tensile Test Compliance|tensile test compliance]]) of the [[Material & Werkstoff|material]]. The injection moulding process orients these fibres in relation to the flow direction. This means that the material properties in the [[Plastic Component|component]] are no longer isotropic but anisotropic (see: [[Anisotropy|anisotropy]]). This means that the material has different properties in the fibre direction and across it.

It is therefore necessary to systematically investigate the relationship between fibre orientation and material properties as a function of material composition.

==The 5-layer model of fibre orientation==

In components manufactured using the injection moulding process, the fibres align themselves along the direction of flow of the matrix during mould filling, particularly in areas with high shear gradients and due to the low flow resistance of the fibres. For this reason, the fibres are oriented parallel to the [[Weld Line|weld lines]] and do not contribute to increasing the [[Strength|strength]] of the matrix material in the weld line ('''Fig. 1''').

[[File:Faserorientierung1.jpg|450px]]
{|
|- valign="top"
|width="50px"|'''Fig. 1''':
|width="600px" |Light microscope image of a cross-section, component made of PA66-CF in the area of the weld line [1]
|}

The flow processes during injection moulding cause a layer structure of fibre orientation due to the parabolic velocity profile. At the edge, the melt solidifies very quickly and the fibre orientation is random. In many [[Thermoplastic Material|thermoplastics]], an almost fibre-free edge zone with thicknesses of up to 300 μm is also observed. In the centre of the cavity, i.e. in the laminar flow region, the fibres are aligned perpendicular to the flow direction. Between the edge layers and the core layer, the melt is sheared, and the fibres orient themselves in the flow direction. A 5-layer model of fibre orientation was developed by [[Menges, Georg|MENGES]] and GAISBÜSCH ('''Fig. 2''') [2].

[[File:Fibre Orientation Fig-2.jpg]]
{|
|- valign="top"
|width="50px"|'''Fig. 2''':
|width="600px" |Velocity profile and fibre orientation during the injection moulding process according to [[Menges, Georg|Menges]] [2]
|}

==Mechanical properties and toughness characterisation==

In the 5-layer model, the [[Glass Fibre Orientation|main orientation of the glass fibres]] is parallel to the flow direction, which is also reflected in the mechanical properties ('''Figs. 3''' and '''4''').

[[File:Fibre Orientation Fig-3.jpg]]
{|
|- valign="top"
|width="50px"|'''Fig. 3''':
|width="600px" |Tensile tests – [[Tensile Test#Tensile test, stress–strain diagram|Stress–strain diagrams]] of polypropylene depending on the injection direction (longitudinal and transverse) and the filler content (20, 30, 40 m.-% glass fibres and 10 m.-% glass fibres + 30 m.-% mineral) [3]
|}

[[File:Fibre Orientation Fig-4.jpg]]
{|
|- valign="top"
|width="50px"|'''Fig. 4''':
|width="600px" |Toughness characterisation of polypropylene depending on the injection direction (longitudinal and transverse) and the filler content (20, 30, 40 m.-% glass fibres and 10 m.-% glass fibres + 30 m.-% mineral) in the instrumented Charpy impact test, a) maximum force, b) deflection at maximum force, c) [[J-Integral Evaluation Methods (Overview)|J-value]], d) [[Extended CTOD Concept|crack opening displacement]] [3]
|}

==See also==

* [[Fibre Agglomeration|Fibre agglomeration]]
* [[ICIT with AE]]
* [[Fibre-reinforced Plastics Fracture Model|Fibre-reinforced plastics fracture model]]
* [[Glass Fibre Orientation|Fibre-reinforced plastics fracture model]]
* [[Interlaminar Shear Strength|Interlaminar shear strength]]
* [[Fibre-reinforced Plastics|Fibre-reinforced plastics]]
* [[Fibre–Matrix Adhesion|Fibre–Matrix adhesion]]

==References==

{|
|-valign="top"
|[1]
|VDI 3822, Blatt 2.1.2 (2024-06): Failure Analysis – Defects of Thermoplastic Products Made of Plastics Caused by Faulty Processing
|-valign="top"
|[2]
|[[Menges, Georg|Menges, G.]], Geisbüsch, P.: Die Glasfaserorientierung und ihr Einfluss auf die mechanischen Eigenschaften thermoplastischer Spritzgussteile – Eine Abschätzmethode. Colloid & Polymer Science, 260 (1982) 1, pp. 73–81; https://doi.org/10.1007/BF01447678
|-valign="top"
|[3]
|Jäger, S.: Einfluss der Faserorientierung auf das mechanische Kennwertniveau medial und thermisch beanspruchter Polypropylen-Glasfaser-Verbunde. Martin-Luther-Universität Halle-Wittenberg, Master Thesis (2010) (see [[AMK-Library]] under B 3-168)
|}

[[Category:Morphology and Micromechanics]]

Fibre Orientation - Revision history