A4 Development and application of BPM for the investigation of mechanics of frozen solid materials

Objective

Temperature plays a crucial role in the behaviour of some natural and engineered particulate fluid systems (PFS). Thus, solid bonds (ice) formation can occur when the temperature drops below the freezing point in moist or fluid-saturated PFS. Resulting in mechanical properties such as stiffness, yield, or fracture stress is of highly important in numerous applications. The main objectives of the project are:

Development and validation of a micromechanical model of solid binding.
Description of the mechanical properties of frozen materials using the Discrete Element Method (DEM)

Supervisor

Prof. Dr-Ing. habil. Dr. h.c. Stefan Heinrich, Prof. Dr.-Ing. Maksym Dosta, Prof. Dr.-Ing. Jürgen Grabe

Methods and work programme

Different experimental and numerical methods are combined to investigate the problem.

Experimental investigations:

Measurement of material parameters in dry state
Analysis of the pore distribution and determination of the degree of saturation
Investigation of the mechanical properties of frozen materials (stiffness and strength)

Numerical investigations:

Simulation of fracture behaviour using the Bonded-Particle Model (BPM).
Automatic parameter adjustment for the determination of the unknown properties

Figure 1: DEM modelling of the mechanical properties.

The temperature range investigated is between -10°and -2°C.

Two models of the d bridges are developed:

Bridge region - single bridges between pairs of particles
Capillary range - bridges between more than two particles

Video: DEM simulation of the fracture of a frozen agglomerate.

Literature

[1] Dosta, M., Dale, S., Antonyuk, S., Wassgren, C.R., Heinrich, S. und Litster, S. (2016): Numerical and experimental analysis of influence of granule microstructure on ist compression breakage. Powd. Techn., 299, S. 87-97.

[2] Kozhar, S., Dosta, M., Antonyuk, S., Heinrich, S. und Schmidt, V. (2015): DEM simulations of amorphous irregular shaped micrometer-sized titania agglomerates at compression. Adv. Powd. Techn., 26, S. 1021-1030.

[3] Chan, T.T.; Heinrich, S.; Grabe, J.; Dosta, M. Microscale Modeling of Frozen Particle Fluid Systems with a Bonded-Particle Model Method. Materials 2022, 15, 8505. https://doi.org/10.3390/ma15238505