Reinforcement

The role of reinforcement in composite materials is primarily to add mechanical properties to the material such as strength and stiffness. However, electrical properties also depend on the reinforcement, and the type of reinforcement is therefore of decisive importance for the properties of a profile. The most common types of reinforcement are fibreglass, carbon fibres and aramid fibres. Fibreglass adds good all-round properties to the material, while carbon fibres provide high stiffness. Aramid fibres enable profiles to withstand impact. Fibreglass-reinforced profiles provide electrical insulation and electromagnetic transparency, whereas carbon fibres result in electro-conductive profiles.

Finally, the orientation direction of reinforcement is of great importance for the properties of finished products in relation to load-bearing capacities.

The profiles manufactured by Fiberline Composites A/S are a combination of various types of roving and different types of complex weaves and mats.

Structural profiles are often subjected to loads that are transversal to the length of the profile (i.e. transversal to the direction of pultrusion), and these profiles must often be capable of resisting pulling and similar stress caused by bolt removal, etc. Therefore, not only smooth unidirectional roving is used, but also roving with some of the fibres oriented transversely. In addition, mats and weaves with different fibre orientations are used.  Mats and weaves with fibre orientations of between 45° and 90° contribute primarily to improving resistance to stress caused by removal of bolts and mechanical properties in the transverse direction. The combination of roving and mats can be designed according to the requirements made to the individual profile. The content of the reinforcement in Fiberline structural profiles is normally 60% according to weight. All structural profiles contain combinations of mats and weaves. Therefore, Fiberline structural profiles always comply with the mechanical properties which are stated in this Design Manual.

Types of roving

Unidirectional

Spun

Mock

Types of mat

Continuous mat

Random fibre orientation

Weave

0º/90º

Complex mat

0º/90º membrane + random fibre orientation

Bidirectional complex mat
0º/±45º/90º weave + random fibre orientation

If a profile will be used in a corrosive environment, a so-called overlay veil is used which can be thin fibreglass matting, thin thermal plastic polyester matting, or acrylic matting which is placed on the entire profile surface to protect against corrosion of the glass fibres and ensuing deterioration in the mechanical properties of the profile.

The pultrusion process necessitates that a certain number of the fibres are oriented in the direction of pultrusion, but apart from this, reinforcement can be structured in innumerable ways, depending upon the load. It is therefore important to note that profiles which are not produced as structural profiles can have mechanical properties that are significantly different from the values which are stated.