PSI - Issue 13

Jiaming Wang et al. / Procedia Structural Integrity 13 (2018) 560–565 J. Wang et al. / Structural Integrity Procedia 00 (2018) 000–000

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Table 1. Parameters for CDP and cohesive zone models Test Model Number

Young’s modulus CDP parameters Traction Stress Fracture Energy

Cohesive Sti ff ness

0.01 / 0.02 / 0.02 N / mm 10 5 MPa / mm 0.04 / 0.4 / 0.4 N / mm 10 5 MPa / mm

Tension

Model 1 6

60 / 18 GPa 70 / 30 GPa

45 / 4 MPa 45 / 4 MPa

2 / 4 / 4 MPa

5 / 10 / 10 MPa

Compression Model 1 3

Fig. 1. CDP mortar model with and without ITZ in (a) Tension; (b) Compression.

Fig. 2. E ff ect of mesh size, loading direction and heterogeneity in (a) Tension; (b) Compression.

To investigate the e ff ect of ITZ on composite behaviour, simulations without and with zCE were performed using elastic-damage (no plastic component) model for mortar. Figure 1 shows that ITZ decreases concrete strength from 3.8 to 3.5 MPa in tension and from 31 to 27.5 MPa in compression. ITZ dissipates more energy in tension when zCE cohesive energy is decreased from 0.03 to 0.01 N / mm, while the e ff ect of zCE cohesive energy is not significant in compression. It should be noted, that di ff erences in softening branches arise from di ff erent damage evolution in the meso-structure realisations. E ff ects of mesh size and loading direction (hence heterogeneity), are illustrated with in Figure 2. Clearly, the influence of these factors is minor, which verifies that the models used are statistically representative, i.e. specimen to aggregate ratio is su ffi ciently large for this study.