Limits...
Injury risk assessment of non-lethal projectile head impacts.

Oukara A, Nsiampa N, Robbe C, Papy A - Open Biomed Eng J (2014)

Bottom Line: Based on the principle that equal rigid wall maximal impact forces will produce equal damage on the head, these limits can be determined for any other projectile.This paper proposes a comparison between the "force wall approach" and two different head models.The first one is a numerical model (Strasbourg University Finite Element Head Model-SUFEHM) from Strasbourg University; the second one is a mechanical surrogate (Ballistics Load Sensing Headform-BLSH) from Biokinetics.

View Article: PubMed Central - PubMed

Affiliation: Royal Military Academy-Department of Weapon Systems and Ballistics-30 Avenue de la Renaissance, 1000 Brussels, Belgium ; Polytechnic Military School, 17 Bordj El-Bahri, Algiers, Algeria ; University of Liège (ULg)-Aerospace & Mechanical Engineering Department (LTAS) - 1, Chemin des Chevreuils, 4000 Liège, Belgium.

ABSTRACT
Kinetic energy non-lethal projectiles are used to impart sufficient effect onto a person in order to deter uncivil or hazardous behavior with a low probability of permanent injury. Since their first use, real cases indicate that the injuries inflicted by such projectiles may be irreversible and sometimes lead to death, especially for the head impacts. Given the high velocities and the low masses involved in such impacts, the assessment approaches proposed in automotive crash tests and sports may not be appropriate. Therefore, there is a need of a specific approach to assess the lethality of these projectiles. In this framework, some recent research data referred in this article as "force wall approach" suggest the use of three lesional thresholds (unconsciousness, meningeal damages and bone damages) that depend on the intracranial pressure. Three corresponding critical impact forces are determined for a reference projectile. Based on the principle that equal rigid wall maximal impact forces will produce equal damage on the head, these limits can be determined for any other projectile. In order to validate the consistence of this innovative method, it is necessary to compare the results with other existing assessment methods. This paper proposes a comparison between the "force wall approach" and two different head models. The first one is a numerical model (Strasbourg University Finite Element Head Model-SUFEHM) from Strasbourg University; the second one is a mechanical surrogate (Ballistics Load Sensing Headform-BLSH) from Biokinetics.

No MeSH data available.


Related in: MedlinePlus

Evolution of the strain energy in the SUFEHM against the impact velocity.
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Figure 16: Evolution of the strain energy in the SUFEHM against the impact velocity.

Mentions: Fig. (16) shows the evolution of the strain energy with the impact velocity. The threshold value for a skull fracture is 865 mJ. Therefore, there is a 50% of probability of skull fracture for temporal impacts at 60 ms-1 and for frontal impacts at 70 ms-1. An example of the predicted fracture for temporal impacts is shown in Fig. (17). The impact velocity of 60 ms-1 for the temporal impact corresponds to an impact force of 2.95 kN. According to the probability curve of Raymond, at this value, the probability of a skull fracture is 5 % (Fig. 13). The injury predictions of the SUFEHM are not the same compared to the force wall approach or Raymond study predictions. The shape, the caliber and the behavior during the impact of the projectiles used in the Raymond study or in the force wall approach (XM1006) are different from the FN303 projectile. That can explain the differences in the injury prediction. These parameters are essential for the occurrence of injuries and are not taken into account in the force wall approach. This issue should be investigated in order to define critical maximum impact forces according to these parameters. Nevertheless, the contact forces predicted by the SUFEHM are coherent with the forces calculated with the force wall approach or measured with the BLSH.


Injury risk assessment of non-lethal projectile head impacts.

Oukara A, Nsiampa N, Robbe C, Papy A - Open Biomed Eng J (2014)

Evolution of the strain energy in the SUFEHM against the impact velocity.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4231376&req=5

Figure 16: Evolution of the strain energy in the SUFEHM against the impact velocity.
Mentions: Fig. (16) shows the evolution of the strain energy with the impact velocity. The threshold value for a skull fracture is 865 mJ. Therefore, there is a 50% of probability of skull fracture for temporal impacts at 60 ms-1 and for frontal impacts at 70 ms-1. An example of the predicted fracture for temporal impacts is shown in Fig. (17). The impact velocity of 60 ms-1 for the temporal impact corresponds to an impact force of 2.95 kN. According to the probability curve of Raymond, at this value, the probability of a skull fracture is 5 % (Fig. 13). The injury predictions of the SUFEHM are not the same compared to the force wall approach or Raymond study predictions. The shape, the caliber and the behavior during the impact of the projectiles used in the Raymond study or in the force wall approach (XM1006) are different from the FN303 projectile. That can explain the differences in the injury prediction. These parameters are essential for the occurrence of injuries and are not taken into account in the force wall approach. This issue should be investigated in order to define critical maximum impact forces according to these parameters. Nevertheless, the contact forces predicted by the SUFEHM are coherent with the forces calculated with the force wall approach or measured with the BLSH.

Bottom Line: Based on the principle that equal rigid wall maximal impact forces will produce equal damage on the head, these limits can be determined for any other projectile.This paper proposes a comparison between the "force wall approach" and two different head models.The first one is a numerical model (Strasbourg University Finite Element Head Model-SUFEHM) from Strasbourg University; the second one is a mechanical surrogate (Ballistics Load Sensing Headform-BLSH) from Biokinetics.

View Article: PubMed Central - PubMed

Affiliation: Royal Military Academy-Department of Weapon Systems and Ballistics-30 Avenue de la Renaissance, 1000 Brussels, Belgium ; Polytechnic Military School, 17 Bordj El-Bahri, Algiers, Algeria ; University of Liège (ULg)-Aerospace & Mechanical Engineering Department (LTAS) - 1, Chemin des Chevreuils, 4000 Liège, Belgium.

ABSTRACT
Kinetic energy non-lethal projectiles are used to impart sufficient effect onto a person in order to deter uncivil or hazardous behavior with a low probability of permanent injury. Since their first use, real cases indicate that the injuries inflicted by such projectiles may be irreversible and sometimes lead to death, especially for the head impacts. Given the high velocities and the low masses involved in such impacts, the assessment approaches proposed in automotive crash tests and sports may not be appropriate. Therefore, there is a need of a specific approach to assess the lethality of these projectiles. In this framework, some recent research data referred in this article as "force wall approach" suggest the use of three lesional thresholds (unconsciousness, meningeal damages and bone damages) that depend on the intracranial pressure. Three corresponding critical impact forces are determined for a reference projectile. Based on the principle that equal rigid wall maximal impact forces will produce equal damage on the head, these limits can be determined for any other projectile. In order to validate the consistence of this innovative method, it is necessary to compare the results with other existing assessment methods. This paper proposes a comparison between the "force wall approach" and two different head models. The first one is a numerical model (Strasbourg University Finite Element Head Model-SUFEHM) from Strasbourg University; the second one is a mechanical surrogate (Ballistics Load Sensing Headform-BLSH) from Biokinetics.

No MeSH data available.


Related in: MedlinePlus