9.3 Test Results and Discussions
281
0.00
0.01
0.02
0.03
0.04
0.05
0
500
1000
1500
2000
2500
Time (s)
Test
Numerical simulation
Impact force (kN)
0.00
0.01
0.02
0.03
0.04
0.05
0.06
0
500
1000
1500
2000
2500
3000
3500
Time (s)
Test
Numerical simulation
Impact force (kN)
0.000
0.005
0.010
0.015
0.020
0.025
0
1000
2000
3000
4000
5000
Test
Numerical simulation
Impact force (kN)
Time (s)
(a)
(b)
(c)
0.000
0.005
0.010
0.015
0.020
0.025
0
1000
2000
3000
4000
5000
Test
Numerical simulation
Time (s)
Impact force (kN)
0.000
0.005
0.010
0.015
0.020
0.025
0
500
1000
1500
2000
2500
3000
3500
4000
Test
Numerical simulation
Impact force (kN)
Time (s)
0.000
0.005
0.010
0.015
0.020
0.025
0
1000
2000
3000
4000
5000
Test
Numerical simulation
Time (s)
Impact force (kN)
(d)
(e)
(f)
0.000
0.005
0.010
0.015
0.020
0.025
0
1000
2000
3000
4000
5000
Impact force (kN)
Time (s)
Test
Numerical simulation
0.000
0.005
0.010
0.015
0.020
0.025
0
1000
2000
3000
4000
5000
Impact force (kN)
Time (s)
Test
Numerical simulation
0.000
0.005
0.010
0.015
0.020
0.025
0
1000
2000
3000
4000
5000
6000
Time (s)
Test
Numerical simulation
Impact force (kN)
(g)
(h)
(i)
0.000
0.005
0.010
0.015
0.020
0.025
0
1000
2000
3000
4000
5000
Time (s)
Test
Numerical simulation
Impact force (kN)
0.000
0.005
0.010
0.015
0.020
0.025
0
1000
2000
3000
4000
5000
Time (s)
Test
Numerical simulation
Impact force (kN)
0 . 0 0 0
0 . 0 0 5
0 . 0 1 0
0 . 0 1 5
0 . 0 2 0
0 . 0 2 5
0
1000
2000
3000
4000
5000
Time (s)
Test
Numerical simulation
Impact force (kN)
(j)
(k)
(l)
Fig. 9.7 Impact force–time histories of specimens a N-2-AF0 b N-3-AF0 c U-2-AF0 d U-2.5AF0 e U-3-AF0 f U-3.5-AF0 g U-4-AF0 h U-3-AF0.01 i U-3-AF0.07 j U-3-AF0.1 k U-4-AF0.05
l U-4-AF0.1
decreases to the minimum value. At the second stage, the indenter and the specimen
fall together and remain in contact, and the impact force fluctuates around a constant
value, i.e., plateau value. At the third stage, the indenter and the specimen bounce
up together after the maximum deflection, and the impact force decreases with the
reduction of contact area until they separate to each other. Herein, the plateau impact
force is calculated by the following equation (Wang et al. 2019b):
281
0.00
0.01
0.02
0.03
0.04
0.05
0
500
1000
1500
2000
2500
Time (s)
Test
Numerical simulation
Impact force (kN)
0.00
0.01
0.02
0.03
0.04
0.05
0.06
0
500
1000
1500
2000
2500
3000
3500
Time (s)
Test
Numerical simulation
Impact force (kN)
0.000
0.005
0.010
0.015
0.020
0.025
0
1000
2000
3000
4000
5000
Test
Numerical simulation
Impact force (kN)
Time (s)
(a)
(b)
(c)
0.000
0.005
0.010
0.015
0.020
0.025
0
1000
2000
3000
4000
5000
Test
Numerical simulation
Time (s)
Impact force (kN)
0.000
0.005
0.010
0.015
0.020
0.025
0
500
1000
1500
2000
2500
3000
3500
4000
Test
Numerical simulation
Impact force (kN)
Time (s)
0.000
0.005
0.010
0.015
0.020
0.025
0
1000
2000
3000
4000
5000
Test
Numerical simulation
Time (s)
Impact force (kN)
(d)
(e)
(f)
0.000
0.005
0.010
0.015
0.020
0.025
0
1000
2000
3000
4000
5000
Impact force (kN)
Time (s)
Test
Numerical simulation
0.000
0.005
0.010
0.015
0.020
0.025
0
1000
2000
3000
4000
5000
Impact force (kN)
Time (s)
Test
Numerical simulation
0.000
0.005
0.010
0.015
0.020
0.025
0
1000
2000
3000
4000
5000
6000
Time (s)
Test
Numerical simulation
Impact force (kN)
(g)
(h)
(i)
0.000
0.005
0.010
0.015
0.020
0.025
0
1000
2000
3000
4000
5000
Time (s)
Test
Numerical simulation
Impact force (kN)
0.000
0.005
0.010
0.015
0.020
0.025
0
1000
2000
3000
4000
5000
Time (s)
Test
Numerical simulation
Impact force (kN)
0 . 0 0 0
0 . 0 0 5
0 . 0 1 0
0 . 0 1 5
0 . 0 2 0
0 . 0 2 5
0
1000
2000
3000
4000
5000
Time (s)
Test
Numerical simulation
Impact force (kN)
(j)
(k)
(l)
Fig. 9.7 Impact force–time histories of specimens a N-2-AF0 b N-3-AF0 c U-2-AF0 d U-2.5AF0 e U-3-AF0 f U-3.5-AF0 g U-4-AF0 h U-3-AF0.01 i U-3-AF0.07 j U-3-AF0.1 k U-4-AF0.05
l U-4-AF0.1
decreases to the minimum value. At the second stage, the indenter and the specimen
fall together and remain in contact, and the impact force fluctuates around a constant
value, i.e., plateau value. At the third stage, the indenter and the specimen bounce
up together after the maximum deflection, and the impact force decreases with the
reduction of contact area until they separate to each other. Herein, the plateau impact
force is calculated by the following equation (Wang et al. 2019b):