Impact testing

Critical infrastructures, such as nuclear power plants, water dams and chemical process plants are inherently vulnerable to external hazard events such as airplane crashes, seismic loads and explosions. To increase confidence in the structural analyses, the models and methods have to be validated with respect to experimental results.

For over two decades, VTT has led the way in impact testing, focusing on the effects of extreme events on reinforced concrete structures. Our state-of-the-art facility uses pressurized air to accelerate projectiles to precise velocities. For example, we can propel a 270 kg projectile to a velocity up to 160 m/s.

We work primarily with reinforced concrete slabs as impact target structures, with span up to 3.5 m and thickness up to 0.5 m, but our versatile setup allows us to test various mockup structures, tailored to specific research requirements. We can explore a multitude of physical phenomena, including bending and punching of target slabs, inclined impact, projectile behavior, impact force dynamics, vibration propagation, scale sensitivity and even liquid dispersal patterns. Our new testing facility also generates shock waves in air, enabling detailed studies of blast load effects on structures.

During each test, we conduct extensive measurements capturing displacements, velocities, accelerations, strains and forces. Every impact test is meticulously simulated using advanced numerical computational tools, complemented by semi-empirical methods for accuracy and reliability.

The testing facility can also be used to research and develop protective structural elements, advancing innovation and safety measures. In addition to tailored customer cases, the facility has been used for international OECD benchmarks and, first of all, for a continuous international research project IMPACT. The 5th phase of this project is planned to start in 2026, and new partners are welcome to join it.