# Calculating Stress experienced by fibre composite.

• olski1
Hence, the stress on both materials should be the same. In summary, the stress taken up by the fibres in the longitudinal direction of a continuous aligned composite with a load of 25kN applied and a diameter of 2cm is 198.91 Mpa. This is determined by calculating the ratio of the fibre load to the composite load and using the formula for stress to find the stress on the fibres.
olski1
Hi,

I need to find the stress taken up by the fibres in the longitudinal direction, when a load of 25kN is applied to a continuous aligned composite with the diameter of 2cm. 60% matirx with E=2.8Gpa and 40% glass fibre E=73Gpa.

Attempt at solution
Known values

V_m = 0.6, E_m = 2.8 Gpa ,
V_f = 0.4 , E_f = 73 Gpa
Cross sectional area A_C=πr^2= π〖(0.01)〗^2=3.142 ×〖10〗^(-4) 〖 m〗^2

i first found,
F(fibre)/F(composite) = ((73×10^9×0.4)) / (73×10^9×0.4)+(2.8×10^9 )(0.6×3.142 ×10^(-4)) => F(fibre) = 24999.548 N

Then using stress= F/A, Where A(fibre) = V(fibre)*(A(comp))
therefore, stress on fibre is 198.91 Mpa

Is that the right method and answer?

One can check the answer against the average stress (load/area), and realize that assuming the two materials are of the same length, and that continuity applies, they must exhibit the same strain.

## 1. How is stress calculated in fibre composites?

The stress experienced by fibre composites is calculated using the formula σ = P/A, where σ is the stress, P is the applied load, and A is the cross-sectional area of the composite.

## 2. What factors affect the stress experienced by fibre composites?

The stress experienced by fibre composites is affected by factors such as the type and orientation of the fibres, the matrix material, the loading conditions, and the manufacturing process of the composite.

## 3. How do you determine the maximum stress a fibre composite can withstand?

The maximum stress a fibre composite can withstand is determined by performing mechanical tests, such as tensile, compressive, or flexural tests, on a sample of the composite. The stress at which the sample fails is considered the maximum stress the composite can withstand.

## 4. What is the difference between tensile and compressive stress in fibre composites?

Tensile stress is the stress experienced by the fibres in the composite when pulled in opposite directions, while compressive stress is the stress experienced when the fibres are pushed together. Tensile stress is typically higher than compressive stress in fibre composites.

## 5. How can we reduce stress in fibre composites?

Stress in fibre composites can be reduced by selecting appropriate fibre and matrix materials, optimizing the fibre orientation, and designing the composite structure to distribute the load evenly. Proper manufacturing techniques and quality control can also help reduce stress in fibre composites.