Andreas Heine
Fraunhofer Institute, Germany
Characterizing the response of protective materials and structures toward hypervelocity impact and high-intensity laser irradiation
Abstract:
Dynamic testing against relevant threats is key for the assessment of materials and structures regarding their suitability for protective applications. Ballistic and blast testing is available at many institutes around the world. In this presentation, we focus on two less widespread though quite important experimental capabilities existing at Fraunhofer EMI.
With light-gas guns, impact velocities of more than 7 kilometers per second are possible in laboratory experiments. The extra-large light-gas gun operated at Fraunhofer EMI is capable to achieve such velocities with accelerated masses of up to 100 grams. That range of possible test parameters is accessible only at a few laboratories worldwide, and for facilities in Europe, this combination of maximum velocity and mass is unique. In combination with flash X-ray and electro-optical diagnostics, it allows studying the interaction of projectiles and targets in a domain relevant for air defense and space applications. An example in this regard are impacts of hypervelocity fragments onto composite materials, modeling wall structures representative of missiles.
A fully different loading regime on a different time scale is generated by laser radiation of high intensity. Related processes of laser-matter interaction are studied with a 120-kilowatt continuous-wave laser at the institute. In general, the thermomechanical target response is strongly dependent on irradiation time, laser power, beam size, as well as on atmospheric conditions influencing the laser beam. In this context, varying properties of laser spots on the target are simulated experimentally, and the resulting effects on materials are observed in the optical and infrared spectral ranges as well as through target damage assessment. These types of characterization are necessary, for example, when developing protective materials, ensuring the functionality of structures in an environment where laser effectors are applied.
Exemplary results from impact and laser experiments are shown. As an outlook, it is demonstrated how these already relatively unique experimental capabilities will be combined for assessing the effects of hypervelocity projectiles against strongly heated structures.
Biography:
Dr. Andreas Heine is the head of the impact physics department at the Fraunhofer Institute for High-Speed Dynamics (EMI). He has been working in the fields of terminal ballistics, impact physics, explosion mechanics, light-gas guns, and the related dynamic material behavior for 20+ years. Dr. Heine has authored 60+ scientific publications, is serving on the scientific committee of the Lightweight Armor Group (LWAG), was a co-organizer of the 2024 International Conference on Impact Loading of Structures and Materials (ICILSM), and is an editorial advisory board member of the International Journal of Impact Engineering (IJIE). As the department head, he also oversees research activities in the fields of high-intensity laser-matter interaction, additive design and manufacturing, and applications of artificial intelligence.