Continuous fibre composite transverse loading

[olski1]

Why is the traverse loading strength of continuous fibre reinforced composites weaker compared to the longitudinal strength?

I sort of arrived at the conclusion, that since the composite is in an isostress state and due to the fibre having a very low tensile strength in the transverse direction. The majority of the mechanical properties relies on the matrix strength, which is usually lower than that of the fibre, thus leading to early on set of failure.

Is it also due to the shear stress created at the fibre ends? also, why do the fibres have a low tensile strength in the transverse direction?

Any help would be greatly appreciated :)

 

[gomoman]

traverse strength is depend on many factors such as the interface bond strength, the properties of matrik and reinforcement, the presence of voids etc. unlike longitudinal strength, it only depend on single factor ie the fibre strength.
yes i agree with u that, when tensile test is done in tranverse direction, the fiber have a negative effect, the composite is rely on the properties of matrix only.

 

[Studiot]

fibre having a very low tensile strength in the transverse direction

Some fibres do, eg graphite, some do not eg steel. So your theory does not hold water.

the composite is rely on the properties of matrix only.

This statement is never true.

traverse strength is depend on many factors

This is true and also applies to the stength in any direction.

Perhaps the most important factors affecting the strength of a fibre composite - apart from the obvious strengths of the components - are the lengths, orientation and lay of the fibres.

 

[Kmenex]

and how would those lengths, orientations and lay of fibers affect the composite?

 

[alphy]

I can provide some insights into the reasons for the lower transverse loading strength in continuous fibre reinforced composites.

Firstly, it is important to understand that the strength of a material is determined by its microstructure and the arrangement of its constituent components. In the case of continuous fibre reinforced composites, the fibres are arranged in a parallel orientation along the longitudinal direction, which is the direction of the applied load. This results in a high strength in the longitudinal direction as the fibres are able to resist the tensile forces effectively.

However, in the transverse direction, the fibres are arranged perpendicular to the applied load. This means that they are not as effective in resisting the tensile forces, resulting in a lower strength. Additionally, the fibres are also subjected to shear stress at their ends, which can further weaken their strength.

Moreover, the fibres themselves have a lower tensile strength in the transverse direction compared to the longitudinal direction. This is due to the manufacturing process of the composite, where the fibres are typically aligned and embedded in a matrix material. The fibres are stronger along their length, but weaker when forces are applied perpendicular to their length.

In conclusion, the transverse loading strength of continuous fibre reinforced composites is weaker due to the parallel arrangement of fibres in the longitudinal direction, the presence of shear stress at the fibre ends, and the lower tensile strength of the fibres in the transverse direction.