Radar Method of Measuring the Velocity of the Fragments
Mario Dobrilović
Round 1
Reviewer 1 Report
The study presented in the paper ‘Modern method of measuring the velocity of the fragments’ focuses on the methods of measuring the velocity of splinters formed during the detonation of the fragmentation generator. There is done a comparison of the results obtained by the usage of a chronometer and aluminum foil and that of a Doppler radar. The aim of the paper is important to define a zone in which people can stay without risking their lives during the demolition works carried out with the admission of explosives. The description of difficulties resulting from the measurements and the methods of their elimination would bring significant benefits to the safety and protection of people. However, there are some rooms to improve this paper.
On line 35, the full name „Smoothed particle hydrodynamics methods and its abbreviation SPH must be given. Then on line 38, SPH could be used
Please add some more explanation in the caption of Figures 8,9, and 10. because the numbers and definitions of axes on these figures are too small to see them.
The sentence ‘Significantly on radar 1 can be observed the negative values of the fragments velocity´ (line 193) must be corrected. For example, ‘Significantly, the negative values of the fragment velocity be observed’.
The velocity of the fragments was measured by two Weibel’s Doppler radars SL-528PE and SL-520P. Hence, it is important to know the specificity of these radars to suppress spurious signals. Maybe the explanation of the specificity of these radars is given in lines 195-197, but the general information provided is not addressed for the above radars.
Line 227, please correct ‘qquestionable result’.
Fig.11 is presented twice, while Fig.12 is absent.
I would like to advise the authors to rename paragraph 5 of this paper for example ‘Conclusion and Advice’ because they along with a short conclusion presented advice on how to improve the fragment velocity measurement by Doppler radars.
Author Response
We would like to express our sincere thanks to the reviewer 1 and the Editorial Office for the constructive and positive comments.
The study presented in the paper ‘Modern method of measuring the velocity of the fragments’ focuses on the methods of measuring the velocity of splinters formed during the detonation of the fragmentation generator. There is done a comparison of the results obtained by the usage of a chronometer and aluminum foil and that of a Doppler radar. The aim of the paper is important to define a zone in which people can stay without risking their lives during the demolition works carried out with the admission of explosives. The description of difficulties resulting from the measurements and the methods of their elimination would bring significant benefits to the safety and protection of people. However, there are some rooms to improve this paper.
- On line 35, the full name „Smoothed particle hydrodynamics methods and its abbreviation SPH must be given. Then on line 38, SPH could be used.
As noted above, this has been corrected.
- Please add some more explanation in the caption of Figures 8,9, and 10. because the numbers and definitions of axes on these figures are too small to see them.
Because the figures 8, 9, 10, 11 are screens imported from the radars software, in the captions were added some explanations with definitions of the axes. Moreover the figures are resized as much as possible.
- The sentence ‘Significantly on radar 1 can be observed the negative values of the fragments velocity´ (line 193) must be corrected. For example, ‘Significantly, the negative values of the fragment velocity be observed’.
Corrections have been made as suggested.
- The velocity of the fragments was measured by two Weibel’s Doppler radars SL-528PE and SL-520P. Hence, it is important to know the specificity of these radars to suppress spurious signals. Maybe the explanation of the specificity of these radars is given in lines 195-197, but the general information provided is not addressed for the above radars.
The explanation given in lines 195-197 (by Weibel support team) describe generally problem of the spurious signals, but in the next sentence we can find information addressed to the radar 1 (SL-528PE). There was added addition in parentheses: (like radar 1).
- Line 227, please correct ‘qquestionable result’.
Corrections have been made as suggested.
- Fig.11 is presented twice, while Fig.12 is absent.
Corrections have been made as suggested.
- I would like to advise the authors to rename paragraph 5 of this paper for example ‘Conclusion and Advice’ because they along with a short conclusion presented advice on how to improve the fragment velocity measurement by Doppler radars.
Corrections have been made as suggested.
Reviewer 2 Report
Recommendation are given in uploaded document.
Comments for author File: 
Comments.pdf
Author Response
We would like to express our sincere thanks to the reviewer 2 and the Editorial Office for the constructive and positive comments.
- I suggest that in the article title you change word “modern” with word that describe applied method.
Corrections have been made as suggested. The word “modern” was changed to “radar”.
- Flay rock impact in quarries and mines, explosive usage opposite than ammunition, is different in physics and materials. Also, in article you do not deal with that phenomena. I suggest that you erase references and text related to civil blasting techniques. Abstract and introduction chapter.
Corrections have been made as suggested. Civil themes have been removed from the abstract and introduction.
- Line 41. If you are referred to reference, it will be better to provide explosives that are used in experiment, rather then formulation “with different explosives”.
Corrections have been made as suggested.
- Line 51 state about reasonable agreement between …….. Please support that with numbers, because “reasonable” can be very subjective
The authors did not provide specific values describing the comparison of the results of the experiment and the simulation, therefore we added additional comments in the text: “According to the author's conclusions, analysis and comparison of the results obtained from the stationary tests and from the simulation show that the mean total number of fragments created as well as the number of fragments in the particular mass ranges are very close. The highest differences occur in the number of fragments of the lowest mass range. The differences result from the fact that during stationary tests it is very hard to recollect such small elements and that is why the full mass of the casing was not recovered. However with the increase of fragment mass the agreement between the simulation results and the experiment rises [15]”.
- Presented numerical simulation from reference (15) have no obviously connection to research presented in paper, only example of the modelling. Please, link those aspect or describe data that income in modelling in exact manner.
The authors of the publication [15] compares the number and size of fragments obtained in the experiment and numerical simulation. Enabling the possibility to compare the velocities of fragments in the experiment and simulations is an important aspect of the verification of the adopted numerical model. An addendum has been added at the beginning of the last paragraph of the introduction: “With reference to the research results obtained by the authors of the publication [15]…”
- Please add legend and measurement units at fig 2.
Corrections have been made as suggested.
- It will be useful to provide some numbers about determination of splinters properties regarding to mass distribution, velocity, energy and according to that efficiency
The information regarding determination of the splinters properties are given in the end of introduction in references [16-21]. Moreover is added the sentence…the kinetic energy of the effective fragment should not be less than 78 Joules [16]…
- There are some other velocity measurement methods, like laser method, photonic Doppler method, high speed photography. I will be good if you can mention other available methods.
The additional sentence was added in the Conclusions and Advice paragraph.
- Please explain screens of the radars plot. In which way particular fragment trace was identified.
The Figure 6 present the configuration of the Doppler radars and idea of measurement.
Radar 1 scanned the arcuate section of the plate from its inside. This registered the signals of fragments moving towards it, reflected from the inner surface of the plate.
Radar 2 emitted the very thin radiation beam through the mirror and was able to recorded the fragment moved in a straight line registered the velocity of the splinters (directly from the radar point of view).
- Regarding the test results, on specific impact traces on screen it is recognized specific splinter. In which manner is that performed and how other splinter traces are eliminated? What are dimension of effective screen area in that case?
Generally the effective distribution of fragments is determined by the number of holes in the control plates. In the assumption, the spread of the fragments should be circularly symmetrical. Plates are selected in such a way that their height corresponds to the average height of men (about 180 cm). Their thickness should be chosen so that the strength corresponds to a board of pine one inch thick. The radial segments of the control plates are allocated like on fig. 6 and 7, each correspondingly farther from the next. Two penetrations holes makes by splinters in the area 1,8 m high and 0,5 m width give positive results of the effectiveness.
- In conclusion you have mentioned bullet trap. Did you use it in described test or you mentioned it in way of recommendation for further test?
We mentioned it in way of recommendation for further tests.
