First Period Summary

The project successfully accomplished its goals at the end of the first period.

The main progress beyond the state of the art and associated impact are summarised below:

  1. A new resin system was designed with nanofiller for improved energy absorption for aerospace applications. Then a new use of basalt fiber for impact absorptions was suggested with convincing initial results.
  2. Developed new sample geometries, test setups and measurement techniques to accurately characterize the composite materials under high dynamic loading, and study the dynamic wave propagation within structures.
  3. A new regularisation technique for reducing and removal of mesh dependency is under development to balance effects of the heterogeneous microstructure on local continua and keep the boundary value problem of softening (damaged) continua well-posed. It is not commercially available and it is being tested within the software DYNA3D. Coupling SPH to FE could lead to better modelling hence designing and understanding of composite materials under extreme loading. This will lead to lighter structures and CO2 emissions.
  4. New damage and meso-scale models were developed to describe materials behaviour under dynamic loading. The material model able to describe shock wave formation and propagation in composite with long fibre reinforcement coupled to a physically based damage model is not currently available in any commercial software and initial validation demonstrated that it is well above the current state of the art. The new material models under development would allow better design of aeronautical structures and lead to a new “right at first time” design philosophy and could extend the working boundary of composite materials.
  5. Full field optical strain measuring instruments, namely the shearography and the high speed 3D DIC instruments are being developed to experimentally measure surface strain components over the field of view at a very high-temporal (μs) and spatial resolution (sub-millimetre). These experimental results will improve material characterization techniques allowing for development of new and improved material models.
  6. Development of smart impact sensing concept based on high-speed fibre-optic sensors and piezosensor networks makes a new level of in situ monitoring of the extreme dynamic loading feasible. The “Supergator” FBG interrogator developed by TFT reaches beyond state of the art performance with 1Mhz sampling rate and resolution below 1.0 pm at a dynamic strain range more than 5%. This is possible due to a novel combination of a spectrometer and an interferometer approaches in a single photonic integrated circuit, which provides significant advantages in size and cost of the interrogator. Integrated sensors and the peripherals as part of SHM concepts capable of sensing impact loadings provide a valuable contribution for the involved aircraft manufacturers towards more efficient and more intelligent structural components.
  7. Development of algorithm for linear and nonlinear phased array 3D imaging of damage in impacted samples were performed. 3D volume measurement techniques for post event damage characterisation indirectly contribute to safety of the air transport industry. More accurate and reliable assessment of impact damages (e.g. reliable detection and characterisation of barely visible impact damages and defects, accurate damage sizing, information on damage 3D structure) can be coupled with remaining life predicting tools and measures for repair organisation.

Extreme CPD