Open Access

In the field of explosive reactions, there is a type of explosive effect that lacks a sufficient database and reproducible experiments regarding biomechanics. It concerns the primary explosive effect. It is defined as pure shock wave of the explosion. The physical behavior of the shock wave when interacting with different types of tissue and, in particular, the subsequent transitions of the shock wave, have barely been investigated. The transition of the shock wave into other materials is the focus of the research Therefore, the aim of the investigations is the development of a multidisciplinary method to investigate shock wave behavior in various generic tissue simulants under the most reproducible conditions possible with realistic loads in an experimental test series with short set-up times. An autoclave is used to generate the pressure waves. A simplified torso model consisting of ballistic gelatin is used as a simulant. In this paper, the influence of protective equipment on the pressure load in the tissue simulant is investigated. For this purpose, consecutive test setups are used. First, the behavior of ballistic gelatin as a tissue simulant is investigated. Then, the simplified torso model is covered with typical combat clothing consisting of four layers. Afterwards a currently used UHMWPE ballistic protective plate is placed in front of the simplified torso model. Finally, the combat clothing and the protective plate are examined in combination. Three cast-in pressure sensors are used as measuring devices, as well as an acceleration sensor attached to the protective plate. The experiments show that the maximum overpressure in a model rotected by combat clothing and the protective plate can be reduced by 95%. However, the propagation speed of the shock wave within the simplified torso model increases from 1535.5 m/s to 2204.5 m/s. This shows that even protective equipment, which is not primarily intended to protect against blast, offers a significant reduction in the pressure load in the protected area. On the one hand it is caused by the media transition from air to PE and the resulting higher reflection of the acceleration of the transmitted wave within the simulant. On the other hand, it is also reduced due to the damping and dispersion caused by the clothing layers.

Die Thematik "low-level blast", als Dauerwirkung aufgrund von Training und Einsatz für Soldaten und weitere Einsatzkräfte relevant, wird im Hinblick auf den aktuellen Stand der Forschung und den Arbeitsschutz beleuchtet.

Die Thematik "low-level blast" (LLB) wird im Hinblick auf ihre Bedeutung für den Arbeitsschutz des Soldaten in Trainings- und Ausbildungssituationen beleuchtet, dabei der aktuelle Stand der Forschung sowie das abgeschlossene wehrmedizinische Sonderforschungsvorhaben, gemeinsam mit dem Bundeswehrkrankenhaus Berlin und weitere Arbeiten der BAM, vorgestellt.

In order to gain an understanding of the Low Level Blast (LLB) exposure of soldiers when using weapon systems, it is necessary to characterize these weapon systems with regard to their overpressure effect [1]. Carrying out static measurements of weapon systems in the rough terrain of firing ranges and training areas poses a challenge for sensitive measurement technology. Furthermore, soldiers are often exposed to LLB in dynamic situations [2]. Therefore, commercially available blast gauges are often used, which, however, are not sufficient for high-resolution measurement of overpressure exposures with academic requirements due to their intended use [3]. Static measurement setups, such as with penile probes, must be used to characterize weapon systems, but they cannot make valid statements about the real load on dynamically behaving soldiers. However, this real load on the soldier is essential in order to be able to adequately assess the potential resulting medical effects. As part of this challenging measurement task, a prototype of a self-sufficient, high-resolution measurement system is presented, which can be used by an operator in dynamic situations without interference. The complete measuring chain was realized as a self-sufficient unit. The system is based on a 20-liter backpack system, which contains the power supply, the measuring amplifier and the measuring card. The measuring computer is attached to the front of the backpack to allow quick access. The measuring system is capable of recording four channels with a sampling rate of up to 2 MHz. Piezoelectric integrated charge pressure sensors are used as a high-resolution pressure sensor (type: PCB138B32). The pressure sensor is placed on a XX- carrier plates with the dimensions XY × YY. The pressure sensors are attached at the typical positions for Blast-Gauges measurements, like on the left shoulder, on the upper chest and on the back of the head. At the same time, commercial blast gauges are placed at the positions of the pressure sensors to qualify the blast gauges (type: B3 Blast Gauges Gen 6). The measuring system is referred to as a “Sensor Carrier Operator (StEk)”. As part of the functional testing of the measurement system, tests are carried out with hand weapons. For this purpose, a soldier is equipped with the StEk and blast gauges. The handguns used are the pistole P8 (caliber 9 mm) and the long rifle G36 (caliber 5.56 mm). The firing position is standing freehand. In addition, the soldier carried out an examination of the carrying comfort of the StEk as part of the training. Furthermore, it was evaluated whether the measuring chain was adequately integrated into the measuring system. The quality of the pressure measurement was also examined, whereby a direct comparison was made with the blast gauges. The measurement system presented here enables the combined (static and dynamic) scientific characterization of weapon systems, particularly with regard to overpressure loading.

Background Military and law enforcement personnel are routinely exposed to shock waves from weapon systems and explosive devices during training and operations. Even when such shock wave exposure results in mild traumatic brain injury (mTBI) without abnormalities on routine imaging, persistent neurological symptoms may occur. Yet, the biological processes that link an acute blast wave insult to progressive neuronal dysfunction remain poorly defined. Methods We established Caenorhabditis elegans nematodes as a genetically accessible animal model for blast-related mTBI (br-mTBI). Animals were exposed in gelatin to shock waves generated by a custom-built shock wave generator (SWG), which produces explosive shock waves with an abrupt overpressure peak followed by a negative pressure phase. The resulting pressure-time curves are very similar to the profiles of conventional explosives in free-field setups. To enable mechanistic studies under controlled laboratory conditions, we developed a complementary platform using a medical radial extracorporeal shock wave therapy (rESWT) device. Motor behavior, mechanosensory function, neuronal morphology and cytoskeletal integrity were analyzed during aging. Results SWG-derived shock waves induced immediate but reversible motor and sensory deficits, followed by an accelerated age-dependent decline in movement and touch sensitivity. The rESWT platform accurately reproduced these phenotypes. Touch receptor neurons showed progressive structural abnormalities, including degeneration, alongside acute PTL-1/Tau mislocalization consistent with cytoskeletal injury. Conclusions Defined shock wave exposure is sufficient to provoke long-term neuronal functional decline in C. elegans, accompanied by structural deterioration and premature neurodegeneration. This tractable model enables lifelong phenotyping and mechanistic dissection of how an acute shock wave insult progresses to chronic neuronal dysfunction, and provides a scalable platform for identifying molecular and pharmacological modifiers that promote resilience.