The impulsive acceleration of active protection elements such as armor plates or other terminal ballistics interception devices can preferably be realized by single-stage electromagnetic launcher systems using pancake coils. The technology with controlled multipartite coil assemblies represents a new supplementary topic in the entire field of ballistics with a high growth potential which is not yet exhausted.During the year 1999 a separate test facility with modular structured energy packs (3 50 kJ) has been built up at ISL as a basic installation for testing reinforced or armored coils and multiple-coil systems. Each power supply module comprises one energy storage capacitor, a thyristor stack adapted to maximum charging voltage, a corresponding number of crow-bar diodes and a well-designed coaxial power line serving as a pulse forming network and current limiting reactor. To provide high flexibility these modules can be triggered independently by fiber optic transmitters with an overall jitter lower than 50 ns. Three packs are designed for a maximum charging voltage of 10.75 kV. First measurements have shown that peak currents up to 120 kA per module and current slew rates of more than 2.5 kA/ s can be generated.The paper presented here describes the test facility and the prototype arrangement of a steerable launcher system with two orthogonally assembled pancake coils fed by two of the modular pulsed power supply units described above. The selection of the launch direction is defined by a short delay (only a few microseconds) between the trigger pulses, so that the usual propagation delay time implied by (mechanical) inertia will be avoided. Further on the first investigations and results concerning steerability and electromechanical efficiency will be presented.

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Interaction between large blast and targets can rarely be studied directly, due to cost and practicality considerations. Blast tests using reduced-scale high explosive charges represent an attractive alternative. The first necessary step consists in studying blast propagation in free-field at the considered reduced-scales. The second step focuses on the determination of the blast load around various types of reference obstacles, in order to provide a critical input for numerical simulation. This approach also aims to build simplified models allowing faster risk assessment processes for government agencies. Since 2017, the French Institute for Radiological Protection and Nuclear Safety (IRSN) and the French-German Research Institute of Saint-Louis (ISL) have been studying blast propagation in free-field and in front of a hemi-cylinder at two different reduced scales using Hexomax ® charges. IRSN developed a significant experience on hemispherical blast effect assessment using 42 g reference Hexomax ® charges detonated in contact to a planar surface supporting a hemi-cylindrical obstacle, both equipped with pressure sensors including two types of technologies: piezo-electric and piezo-resistive. Based on this experience, ISL developed its own outdoor blastpad: 333 g Hexomax ® charges are detonated in a factor two up-scaled version of the IRSN test configuration. Similar sensors are flush-mounted on the pad and the surface of an up-scaled version of the IRSN obstacle. To assess the resulting experiments extensibility, blast characteristics were measured at distances ranging between 0.6 and 3.5 m/kg 1/3 from the different charges with or without obstacle. A classic post-processing methodology identified in the literature was applied to determine all peak overpressure values. The results were consequently compared to the directly determined values in order to propose a unified technique of processing overpressure data for reduced-scale blast tests, including various types of pressure sensors. Finally, this work contributes to the optimization of large scale blast tests designed to evaluate structural response.

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