Fibre composite structures for engineering applications shou

Fibre composite structures for engineering applications should be designed to retain structural integrity and remain durable for the intended service life. While in service, composites can lose their functionality by suffering changes in their strength and stiffness properties while still carrying significant loads. In this discussion topic, you need to list the major factors that affect the durability of composite materials/structures. Also, the effects/implications of these factors on the durability and structural performance of the three most commonly used fibres such as glass, carbon and aramid (Kevlar) should be discussed. Support your discussion with appropriate literature.

Solution

Fibre composite structures for engineering applications should be designed to retain structural integrity.There are some factors that affect the durability of the materials given below:

1.The fibre types, relative portions of constituents, manufacturing processes, installation procedures are the main factors that affect the durability.

2.In the sun exposure,the bending strength will be affected.

3.The shear strength also will be decreased slightly.

4.Tensile & compressive stresses act to have stabilising effects on the moisture diffusion, which shows that bending stresses have a comparatively trivial effect on absorption of moisture.

5.Structural design,quality of individual material components,mix proportion parameters,workmanship,curing and exposure environment are also affect the durability.

6.Sometimes the properties with influence in the creep fatigue behaviour of materials will be lost.

The main factors affect the durability of glass,carbon and aramid shown below:

The factors affecting glass strength and therefore durability are:

Size: A critical flaw increases with the increase in the size.

Temperature changes:The hot glass tries to expand while the cold glass does not expand.

State of stress: The holes will be created with the increase of stress.

Mechanical loading rate: These will be damaged when the load will be increased.

Implications: We should apply the stresses only upto the limit. We should carry the precautions while the changing of temperature occurs. We have to stop the applying load before it reaches the proportional limit.Mostly it is better to choose the smaller sizes.

The factors affecting durability of carbon are:

Fibre types: Sometimes the type of fibres affect the durability. The structural stabilty always depends upon the type of fibre.

Manufacturing process: There will be the loss of bonding in between the layers due the process of manufacturing.

Installation procedures: The structural output depends upon the method of installation. The better the quality of installation, the better the structural output.

Implications: We should take precautions during manufacturing. We should not allow the occurance of layer forming in structure. We should make the structure perfect with the good quality constituents.

The factors affecting durability of aramid are:

Material properties: Aramid offer good mechanical properties at a low density. It will produce many losses with the higher insignificant properties.

Structural strength: These materials improve the resistance with the higher tensile strength. The gaps will be formed due the lack of sufficient strength.

Manufacturing process: There will be weak structural formation will be occured due to the improper manufacturing.

Implications: We should not allow the formation of gaps between the layers. We should apply the proper manufacturing process. We need to take some precautions against the environmental conditions. It is better to maintain the sufficient structural strength. With these some implications we can maintain the structural formation in the better state.