Issue 69

M. B. Prince et alii, Frattura ed Integrità Strutturale, 69 (2024) 154-180; DOI: 10.3221/IGF-ESIS.69.12

σ

pl ε = ε -

c

(3)

c

c

(1-d )E

c

σ

pl ε = ε - c0 c

c

(4)

E

σ

pl ε = ε -

t

(5)

t

t

(1-d )E

t

σ

pl ε = ε - t0 t

t

(6)

E

where d is the damage parameter, and σ and ε are the stress and strain of concrete, respectively. The superscripts el and pl refer to elastic and plastic components, respectively, while the subscripts c and t represent compressive and tensile states. The parameter "0" signifies no damage considered. The compression and tension curve used for this study to model concrete is shown in Fig. 4. The damage parameters have been calculated based on the damage model provided by Sidorroff [33] as per Eqn. 7.

σ

(7)

d=1-

ε E

(a) (b) Figure 4: Stress–strain relationship of the concrete-damaged plastic model: (a) compressive stress-strain curve; and (b) tensile stress strain curve. Details of modeling The finite element model was created by generating two parts for the concrete cube and reinforcement. Three-dimensional deformable solid parts have been generated for concrete and reinforcement, and their dimensions are assigned based on Tab. 2. A cylindrical hole was created through the center of the concrete cube with the exact diameter of the reinforcement to ensure interaction between the bonded region of concrete and reinforcement. The rebar was then placed into this hole. In the experiment conducted by Deng et al. [21], PVC pipe was used at the unbonded region to control the embedded length of reinforcement. However, since PVC material properties were unavailable for this study, PVC pipe has not been used in the unbonded region. The assignment of holes with different thicknesses may result in the assignment of complex element types. For instance, in this study, the thickness of different hole sizes led to the assignment of an element type of “tet” or “wedge” shape, which is unsuitable for the desired output. Therefore, the hole size has been kept uniform throughout the concrete. However, no

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