PSI - Issue 73

Lucie Malíková et al. / Procedia Structural Integrity 73 (2025) 94–99 Author name / Structural Integrity Procedia 00 (2025) 000–000

97

4

distances ; see for instance Susmel and Taylor (2008), where this values is thought of as a physical property that corresponds with the structural characteristics of the material as well as with the specific features of the failure processes. Note that this research follows the previous results of the authors, such as Malíková et al. (2024) or Malíková and Miarka (2025). In the former work, the only geometrical configuration with and without a crack at the anchor’s corner is investigated and the stress intensity factors and stress distribution are investigated. The latter works is devoted to analysis of the influence of the anchor’s embedment length on the tangential stress distribution and on the angle of crack initiation. 3. Results of FE simulations and discussion Based on the previous analysis, it was observed that the maximum of the tangential stress distribution around the anchor’s corner best matches the experimental observations of the concrete cone failure. This is in agreement with the well-known MTS criterion (Erdogan and Sih (1963) for more details) which predicts further crack propagation angle from the maximum tangential stress. Note that the anchor’s corner represents (similarly to a sharp crack) a stress concentrator. Particularly, the tangential stress was investigated at selected radial distances around the anchor’s corner. Fig. 3 shows selected results of the tangential stress distribution around the anchor’s corner for various outer anchor’ radii and anchor’s embedment length L em = 50 mm (see Fig. 1 for meaning of angle  ).

Fig. 3. Tangential stress distribution around the anchor’s corner for the specimen with L em = 50 mm and various outer anchor’s radii investigated at the critical radial distance of 5 mm.

It can be seen that the values of the tangential stress decrease with increasing outer radius of the anchor for the selected configuration. Furthermore, the maximum   values for all configurations investigated occur close to the experimentally observed value of 37.5°, see e.g. Eligehausen and Sawade (1989) or Karmokar et al. (2021). The dependences of these  max angles where the tangential stress reaches its maximum are presented in Fig. 4. Results presented in Fig. 4 show several findings. When comparing Fig. 4 (a) and (b), i.e. the results for specimens with different anchors’ embedment lengths, it is clearly seen that a longer anchor causes lower  max angles and thus, the concrete cone failure shape is flatter, and thus more energy is needed to follow the circumferential crack path. From this point of view, concrete specimens with longer embedment of the steel anchors should be more reliable and safer. When the influence of the outer anchor’s radius on the  max angle is analyzed, almost no dependence is observed for shorter anchors, see Fig. 4 (a), and slight decrease of  max for larger outer radii can be seen in Fig. 4 (b) for L em = 250 mm especially at smaller critical distances. This behaviour is again more advantageous in terms of a flatter concrete cone failure shape when the crack needs to overcome longer path towards the specimen surface.