PSI - Issue 73

Kateřina Matýsková et al. / Procedia Structural Integrity 73 (2025) 100 – 105 Kateřina Matýsková, Marie Horňáková / Structural Integrity Procedia 00 (2025) 000 – 000

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The used material model does not resolve individual wood splinters. Their influence is implicitly included in the calibrated macroscopic parameters of the material model. The heterogeneity of the waste material is represented through effective fracture properties derived from experiments. These parameters (Table 2, Table 3) were used for the first simulation. Since the first ATENA simulation results differed significantly from the experimental measurements, the standard deviations of the input parameters (Y oung’s modulus, tensile strength, fracture energy) were initially set to relatively high values in SARA. Using Latin Hypercube Sampling, 20 random parameter sets were generated and simulations performed. From these, the curve closest to the experiment was selected and its parameters were transferred back to ATENA. The updated model in ATENA was then uploaded to SARA, where smaller deviation ranges and another set of 20 simulations were run. This iterative process was repeated eight more times, so in total about 200 simulations were performed. Although SARA allows a larger number of runs, hardware limitations restricted us to batches of 20, since calculations often froze beyond that and previous results were lost. Some generated input combinations also caused failed simulations, typically when higher deviation ranges produced unrealistic values (e.g., fracture energy close to zero). The modified parameters are given in Table 4 and Table 5.

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Fig. 2. Numerical model of three point bending test (left) with shown mesh elements (right).

Table 2. Input parameters of CET0 for the 3DNonlinearCementitious2 material model. Parameter Value Unit Calculation/Experiment/Default Modulus of elasticity 48.5 GPa Experiment Tensile strength 8.27 MPa t = 32 ℎ 2 Compressive strength 89.25 MPa c =0.85 c,cube Fracture energy 101 N/m Calculated from l - d diagram Table 3. Input parameters of CET100 for the 3DNonlinearCementitious2 material model. Parameter Value Unit Calculation/Experiment/Default Modulus of elasticity 35.7 GPa Experiment Tensile strength 6.52 MPa t = 32 ℎ 2 Compressive strength 79.8 MPa c =0.85 c,cube Fracture energy 112 N/m Calculated from l - d diagram