Nonwoven fabric in Ballistic resistance

Ballistic protection is the major area of concern in the case of protective clothing or defence textiles and it is achieved by using nonwoven fabrics in a better way as compared to conventional woven fabrics, says Pravin H Ukey, LG Patil and SS Borikar.
Nonwoven fabrics are broadly defined as sheet or web structures bonded together by entangling fibre or filaments (and by perforating films) mechanically, thermally or chemically. They are flat, porous sheets that are made directly from separate fibres or from molten plastic or plastic film.

The nonwovens industry is one of the areas of the textile market. Not only it is fascinating and economically viable but it is an area experiencing a tremendous amount of growth.

Now a day´s nonwovens are widely used in the field of technical textiles such as protective clothing, geotextiles, medical textiles, etc.

Ballistic protection is the major area of concern in the case of protective clothing or defence textiles and it is achieved by using nonwoven fabrics in a better way as compared to conventional woven fabrics.

Bulletproof fabric is the very important to have the protection from the bullets and other equivalents weapons. It can be made from hard or soft bulletproof material.

The hardness can be of metals such as titanium, aluminium etc. whereas soft can be fibrous materials like nylon based fibres. There are many advantages and disadvantages of using both soft and hard bulletproof material. In spite of all these the soft material is mostly used because of its comfort ability, light weight and better bulletproof effect.

To achieve advancements in body armour performance levels at a reduced weight will not only require further advancements in materials, but the use of models and simulations to develop innovative system designs.

Recent innovations in materials and manufacturing technology during the 20th century led to the discovery of advanced man-made textile materials (such as nylon, fibreglass, Kevlar, and many other synthetic fibres) that have provided body armour with extraordinarily improved ballistic protection levels at a significantly reduced weight-a potent combination of enhancing the effectiveness and mobility of military troops, law enforcement officers, and security personnel.

While those same demands (increased protection at decreased weight) continue today, it is recognised that future improvements will be increasingly difficult to achieve because the financial costs associated with developing new fibres are becoming cost-prohibitive and the time-to-market for their commercialisation remains long term. Many investigations have focused on the construction and analysis of the ballistic resistance models. High-velocity impact response is dominated by stress wave propagation through the material, in which the structure does not have time to respond, leading to very localised damage.

Meanwhile, fibre failure occurs at the point of impact due to local high stresses, and also due to the impact indentation effects related to high fabric deformation. For resistance to low-velocity impact, the ability to store energy elastically in the fibres is the fundamental parameter.

Frictional fibre sliding is the important energy absorbing mechanism used in ballistic fabrics. The energy absorbed due to frictional forces is a continuous function of displacement and is strongly affected by the rate of displacement. So the sliding mechanism of the structure will better than the fracture of the fibres at the high rate of displacement. The displacement will not damage the structure and so the bullets will not pass through the structure. The compound non woven fabric through the needle bonding can be the better solution for this.

Frictional sliding can be a significant contributor to energy absorption if this mechanism can be triggered under impact conditions. An inter-phase that has