Trauma plate

A trauma plate, also known as a ballistic plate or ballistic panel, is a protective plate that is an add-on component or insert to a ballistic vest.[1][2] Its primary purpose is to absorb the ballistic impact of projectiles received and reduce ballistic trauma and blunt trauma transferred to the wearer of the vest. As such, trauma plates supplement the ballistic protection of the section of the vest that they are positioned in.

Trauma plates are most commonly found in the front, rear, and side pockets of a ballistic vest or plate carrier and positioned around the chest, back, and sides of the abdomen respectively. Vests like Dragon Skin do not contain traditional trauma plates, and may use a different form of protection like miniature trauma plates akin to scale armor.

Shapes and sizes

Trauma plates can be found in a variety of sizes and shapes. The most common shapes are rectangle, rounded rectangle, and irregular hexagon.

In concealed vests (vests worn under a shirt), the trauma plates are most commonly 5″ × 8″, with variants including 5″ × 7″, 5″ × 9″, 6″ × 8″, and 6″ × 9″. Thickness (depth) varies based on material and application but rarely exceed 1/4″.

In tactical vests, worn as outerwear, the trauma plates are most commonly 10″ × 12″ with some variation depending on the vest. Thickness varies, depending on material and application, but rarely approaches 1/2".

In specialized/military-grade vests, a considerable portion of the vest is made up of rigid, trauma-plate like inserts. Since they are an essential part of the vest, they are NOT typically considered the same as trauma plates or pads and are typically referred to as inserts, much like the aramid ballistic inserts found in concealed, duty, and tactical vests. SAPI vests are an example of this type of vest. In most SAPI based vests/carriers, the outer vest is made out of and lined with aramid material is made to carry multiple ballistic inserts, typically made out of ceramics. These inserts are shaped to fit the carrier and have sizes that vary depending on the size and shape of the vest.

Materials

Most trauma plates or pads are made of a combination of materials. The following categories denote the primary material used in different plate packages.

Ceramic

Ceramic plates or ceramic armor, typically composed of boron carbide or similar material, are common place in military applications. While materials offer very high ballistic value, they perform poorly in terms dispersing blunt trauma. As a result they are often backed with materials like aramid fabrics, high density plastics, and/or metals. The advantages of ceramic armor is that they are not only lighter than metals, but much harder as well, which enables them to deform most penetrators.

Ceramic material defeats projectiles by shattering it into pieces, decreasing the penetration ability of projectile. Compared to steel or titanium, ceramic plates have inferior multi-hit resistance due to its brittle nature. As such, they are vulnerable to projectiles which hit in a tight grouping, as these create a stress concentration on the plate and shatter the section of plate targeted. [3]

Metal

Most metal trauma plates are made primarily of steel or titanium, although aluminum and various alloys also exist. Metal trauma plates can be used for reducing blunt trauma due to the conductive traits of the material.

Given the nature of the material used, there is a risk for ricochet and spall. To address this, metal plates are often times encased in anti-spall lining designed to trap projectile fragments and spalling. Additionally, plate carriers and bullet resistant vests assist in trapping these fragments.

Fabric

Often called soft trauma plates, these are flexible plates that typically do little to reduce trauma. They are typically composed of layers of aramid fabrics, similar to, if not the same as the material found in the vest. They may also include thin sheets of metal or ultra high molecular weight polyethylene (UHMWPE) to add stiffness and some trauma protection.

Plastic

Multi-layered sheets/plates of ultra high molecular weight polyethylene (UHMWPE) can provide an added ballistic enhancement equal to or even greater than metal plates with less weight. With these, there is the cost of less trauma reduction and the improbable but possible risk of fracture. The layered sheets that exist in each plate, are sometimes separated by high density foam, which provides some compression to aid in dissipating the kinetic energy of an impact. Though this is more often found in cheap polycarbonate plates that provide some trauma reduction, but no ballistic value.

  • UHMWPE plates are often referred to as being ten times stronger than steel. UHMWPE can be strewn into a thread when made, and woven into a fabric that competes in strength, flexibility, and weight to modern aramid fabrics, and is now a commonly used material in vests.

Polymer

Several companies have created viscoelastic polymer compounds capable of a very high degree of energy/force dissipation as a result of shock, vibration, or g-force side loading. The material, and padding made from it, derives its superior energy adsorbing behavior from the unique physical properties of the viscoelastic compound.  The bulk of the compound is composed of a high molecular weight, highly viscous, highly elastic polymer fluid.  The fluid is then compounded with rheological modifiers and other fillers to control the physical and rheological properties of the finished padding compound.  Zoombang is one example of a polymer compound trauma pad (ZB-7 Trauma Pad).

Nanomaterials

As a potential material for future trauma plates and anti-ballistic fabrics, carbon nanotube and nanocomposite materials offer strength to weight ratios that are potentially superior to other materials. For further information on these materials as applied to ballistics, please visit the section on ballistic vest nanomaterials in ballistics. There are plates made of nanomaterials currently available in commercial products.

Special threat plates

Special threat plates (STP), also known as multi-threat, special purpose, rifle, and special application plates, are plates that have a notably higher ballistic rating (NIJ standard) than the vest. There is no standard for materials or ballistics for these plates, though most meet the NIJ Standard for armor type III. Some plates are made of a combination of materials, like ceramic on plastic, plastic on metal, etc.

Some manufacturers may use these labels as marketing rather than enhanced protection.

References

  1. "Ballistic Resistance of Body Armor NIJ Standard-0" https://www.ncjrs.gov/pdffiles1/nij/223054.pdf#page=21
  2. Johnson, Adam. "Trauma Plate." The Virginia Quarterly Review 75.3 (1999): 544.
  3. American Society of Composites (1999). American Society of Composites, Fourteenth International Conference Proceedings. CRC Press. p. 258. ISBN 1566767911.

See also

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