# Experimental and Numerical Study on the Low Velocity Impact Behavior of ABR Pipe
## 6 Summary and Conclusions  
In this paper, 20 low-speed impact tests of ABR pipeline were carried out by using a drop hammer device. Combined with finite element numerical simulation, the dynamic response law of different drop hammer mass and height on pipeline impact was studied.  
The following main conclusions can be drawn:  
1. The contact region displayed distinct frictional traces, with marks transitioning from elliptical to pronounced elliptical shapes as impact energy increased.  
Figure 13: PEEQ nephogram of the inner surface of the contact area.  
2. In this paper, through the quantitative calculation of the energy dissipation coefficient of the ABR specimen, it is proved that the energy dissipation capacity of ABR pipe is good, which can fully dissipate the impact energy.
3. Based on the test results and dimensional analysis method, a calculation method suitable for calculating the peak impact force in the first drop hammer impact process of the pipeline is proposed, which can provide a simple calculation method for ensuring pipeline safety.
4. Obvious plastic deformation occurs in the pipeline during low speed impact, and the failure mode of the pipeline is that the local plastic strain develops too much.
5. The numerical model can well predict the time-history change of impact force and pipeline strain development process in a low-speed impact process.  
Conceptualization, S.H., C.S. and X.X.; methodology, S.H. and C.S.; software, S.H., C.S. and X.X.; validation, S.H., C.S., F.P. and W.L.; formal analysis, C.S. and X.X.; investigation, H.Q.; resources, F.P.; data curation, S.H. and C.S.; writing--original draft preparation, S.H. and C.S.; writing--review and editing, W.L. and S.H.; visualization, S.H., C.S. and X.X.; supervision, S.H. and C.S.; project administration, S.H. and C.S.; funding acquisition, S.H. and F.P. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the Innovation Group Science Foundation of the Natural Science Foundation of Chongqing, China (cstc2020)cyj-cxttX0003), the National Natural Science Foundation of China (51739008), the Key Program of the National Science Foundation of China (52130901) and the Taishan Industry Lead-ing Talent Project Special Fund.  
Not applicable.  
Experimental data and numerical models in the study are available from the corresponding author upon reasonable request.  
The authors declare no conflict of interest.  
The acceleration of drop hammer  
the energy of drop hammer at initial time  
the energy absorbed by the pipeline  
the energy dissipation coefficient of the pipeline  
the napierian logarithm  
the peak impact force in experiment  
the peak impact force according to the Formula (13)  
the acceleration due to gravity  
the height of drop hammer  
the mass of drop hammer  
the mass of specimen  
the contact duration (total duration of the impact event)  
the time during impactor drop and impact event  
the time interval between experimental data collection points  
the displacement of drop hammer  
the velocity of drop hammer  
the impactor velocity at time of initial contact  
the mass per unit length of the pipeline  
the maximum displacement of the pipeline  
the impact coefficient