A trauma pad is a specialized, non-ballistic layer worn directly behind a body armor plate or soft armor panel. Its purpose is to mitigate the blunt force trauma that occurs even after the primary armor successfully stops a projectile. While ballistic armor prevents penetration, a trauma pad absorbs and disperses the residual kinetic energy transferred to the wearer’s body upon impact. This insert reduces the severity of secondary injuries, such as broken ribs or internal organ damage.
The Mechanism of Blunt Force Reduction
When a projectile strikes body armor, the kinetic energy is absorbed by the armor material, preventing penetration. This energy is transferred into the armor plate, causing it to deform inward toward the wearer, a phenomenon known as backface deformation (BFD). The National Institute of Justice (NIJ) standard allows for a maximum BFD of 44 millimeters (about 1.7 inches), a deformation that can still cause injury to underlying tissue and organs.
A trauma pad acts as a buffer zone designed to manage this concentrated energy transfer and limit BFD. It works by dispersing the impact force across a wider surface area of the wearer’s torso, significantly reducing localized pressure. By distributing the force, the trauma pad lessens the peak force felt at any single point, mitigating the risk of blunt force injuries like bruising and rib fractures. Tests have shown that adding a trauma pad can decrease BFD by over 30 percent in some armor systems.
Materials and Design Considerations
Trauma pads are engineered from materials selected for their energy-absorbing and energy-dissipating characteristics, rather than their ability to stop bullets. Common materials include high-density foam, proprietary polymer blends, and layered non-Newtonian materials. High-density closed-cell foam is frequently used due to its ability to compress and rebound, absorbing impact energy through controlled deformation.
Some advanced pads utilize non-Newtonian materials, which instantly solidify or dramatically increase their viscosity upon sudden, high-force impact. This hardening allows the pad to create a temporary, more rigid surface, effectively spreading the energy across the entire area and reducing concentrated force. Design variations focus on optimizing compression and rebound properties to maximize energy absorption without adding excessive thickness or weight. Trauma pads generally range in thickness, often being around a quarter-inch thick, balancing protective capabilities with low-profile wearability.
Placement and Role in Ballistic Systems
A trauma pad is always positioned between the primary ballistic protection and the wearer’s body, sitting inside the plate carrier or vest pocket flush against the armor plate. This placement ensures the pad is the last layer of defense before the kinetic energy reaches the body. The trauma pad’s role is purely supplementary; it provides no ballistic protection and does not increase the armor’s certified threat level.
The trauma pad must be distinguished from soft ballistic armor, which is designed to stop fragmentation and lower-velocity projectiles. The trauma pad is a non-ballistic insert focused solely on mitigating the secondary effects of impact, while soft armor is a primary defensive layer. Whether used with hard armor plates (such as ceramic or steel) or flexible soft armor panels, the trauma pad is an addition to the protective system to manage non-penetrating trauma resulting from a successful ballistic stop.