262
8 Response of UHPCC-FST Subjected to Low-Velocity Impact
Table 8.10 CS model parameters of steel tube
Density
(g/cm 3 )
Elastic modulus
(GPa)
Poisson’s ratio Yield stress
(MPa)
Tangent modulus
(GPa)
Rupture strain
7.85
206
0.3
318.5
0.8
0.23
E t =
σ u − σ y
ε u − ε y
(8.25)
where σ u and σ y are the ultimate stress and yield stress, respectively. ε u and ε y are
the ultimate strain and yield strain, respectively. Based on Fig. 8.1 and Table 8.4,
the values of σ u , σ y , ε u and ε y are taken as 507 MPa, 318.5 MPa, 0.23 and 0.0036,
respectively.
8.5.1.3 Mesh Size Sensitivity
Element size has a great influence on the results of numerical simulation. In order
to analyze the mesh size sensitivity, the C-5 case was taken as an example and the
numerical test of mesh convergence was performed firstly. Figure 8.21 shows the
deflection-time histories of C-5 case at Point B obtained by using four different
specimen mesh sizes, i.e., 6 mm, 10 mm, 16 mm and 20 mm. It can be seen that
16 mm and 20 mm mesh predicts relatively larger deflections than 6 mm and 10 mm
Fig. 8.21 Deflection-time histories of C-5 case at point B for various mesh sizes, reprinted from
Wu et al. (2019), copyright 2020, with permission from Elsevier
8 Response of UHPCC-FST Subjected to Low-Velocity Impact
Table 8.10 CS model parameters of steel tube
Density
(g/cm 3 )
Elastic modulus
(GPa)
Poisson’s ratio Yield stress
(MPa)
Tangent modulus
(GPa)
Rupture strain
7.85
206
0.3
318.5
0.8
0.23
E t =
σ u − σ y
ε u − ε y
(8.25)
where σ u and σ y are the ultimate stress and yield stress, respectively. ε u and ε y are
the ultimate strain and yield strain, respectively. Based on Fig. 8.1 and Table 8.4,
the values of σ u , σ y , ε u and ε y are taken as 507 MPa, 318.5 MPa, 0.23 and 0.0036,
respectively.
8.5.1.3 Mesh Size Sensitivity
Element size has a great influence on the results of numerical simulation. In order
to analyze the mesh size sensitivity, the C-5 case was taken as an example and the
numerical test of mesh convergence was performed firstly. Figure 8.21 shows the
deflection-time histories of C-5 case at Point B obtained by using four different
specimen mesh sizes, i.e., 6 mm, 10 mm, 16 mm and 20 mm. It can be seen that
16 mm and 20 mm mesh predicts relatively larger deflections than 6 mm and 10 mm
Fig. 8.21 Deflection-time histories of C-5 case at point B for various mesh sizes, reprinted from
Wu et al. (2019), copyright 2020, with permission from Elsevier