The new project (working title IMPACT V) is under planning phase.
Estimated start time (testing activities): 2027
Estimated duration: 4 years
Estimated participation fee: 200 – 240 k€ divided upon 4 years
Shortlist of topics to be studied:
- scaling effect
- bending damage up to failure
- curved structures
- steel-concrete composite structures including inclined impacts
- arching effect for impacts near moment transferring supports
If you have any questions about the project or are interested to join it, please contact Mr. Ari Vepsä.
History
VTT has coordinated IMPACT projects since 2004, developing capabilities concerning external impacts on civil structures in collaboration with an international network of experts. The work has greatly increased understanding of related phenomena and enhanced analysis capabilities in the field. During IMPACT projects I-IV (2004-2025) we have gained valuable experimental data on the behaviour of reinforced target structures under various types of impacts. From the test result database, it is possible to predict the quantitative response and the failure mode of the protective structure as a function of the design parameters of the target structure and the type and severity of the impact. Such information is valuable for setting engineering design limits. The following topics have been studied in the project:
- Perforation limit of simply supported rectangular slab under rigid projectile impact. Varied parameters: slab thickness, bending /shear reinforcement ratio, pre-stressing state, amount of corrosion.
- Local shear cone formation and shear reinforcement tensile strain of simply supported rectangular slab under semi-rigid projectile impact. Varied parameters: bending /shear reinforcement ratio, impact velocity, distance of load application point to supports.
- Global bending reinforcement tensile strain and global displacement of simply supported rectangular slab under soft projectile impact. Varied parameters: slab inclination, bending /shear reinforcement ratio, impact velocity, liquid filling.
- Vibration propagation in mock-up structures under soft projectile impact. Varied parameters: structure geometry.
- Size-effect study to assess transferability of aforementioned test results obtained on small scale specimens.
In addition, important progress in the domain of computational studies have been made to enhance the toolkit available for computational predictions of airplane crashes. However, during the course of the project, it has been noticed that there are still many knowledge gaps. In particular, the following topics have been raised:
- Generalization of impact studies carried on simply supported square slabs to more complex geometries, involving cylindrical and dome shapes.
- Assessing the effect of concrete ageing on impact resistance.
- Conducting repetitive tests to assess reproducibility and scattering of test results and statistical significance of second order phenomena.
- Conducting dedicated tests to discover material behaviour of concrete and steel under high strain rates.
- Continuation of some previously studied topics, which contain still open questions. In particular, the size-effect study requires more testing to provide conclusive answers.