ROMANIA
NATIONAL DEPARTMENT OF DEFENSE
Military Technical Academy
Col. (r) Eng. Ştefan DUMITRESCU
DOCTORATE THESIS
(Abstract)
Scientific guide :
Col. (r) Eng. Vasile NĂSTĂSESCU, Ph. D.
BUCHAREST
2004
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Abstract
SUMMARY
Chapter 1 Introduction
1.1 General considerations……………………………………………………..
1.2 Thesis objectives……………………………………………...……………
1.3 Thesis structure……………………………………….................................
Chapter 2 At present stage concerning the problems and the study of
impact phenomenon among projectile and armour
2.1 Principal characteristics of modern armours…………..…………………
2.2 Short historical evolution of the perforating kinetic type projectiles………
2.3 Characteristics of perforating phenomenon among antitank kinetic
ammunitions and armour ……………………………………….................
2.4 Study of phases of the perforating phenomenon of antitank kinetic
type ammunition...………………………………………………………….
2.5 Conclusions.………………………………………………………………...
Chapter 3 Modern methods utilize for perforating parameters calculus
3.1 Mathematical modeling of perforating phenomenon …………………...
3.2 Modern methods utilize for major perforating parameters calculus of
antitank kinetic type ammunition..………………………………………..
3.3 Conclusions ………………………………………………………………...
Chapter 4 Calculus of perforating parameters for BR-412B projectile,
caliber 100 mm
4.1 Description of projectile..………………………………………………….
4.2 External ballistics parameters calculus……..…………………………….
4.3 Terminal ballistics parameters calculus……..…………………………….
4.4 Conclusions ………………………………………………………………...
Chapter 5 Calculus of perforating parameters for APFSDS-T projectile,
caliber 100 mm
5.1 Description of projectile..………………………………………………….
5.2 External ballistics parameters calculus……..…………………………….
5.3 Terminal ballistics parameters calculus……..…………………………….
5.4 Conclusions ………………………………………………………………...
Chapter 6 Experimental methods concerning determination for perforating
parameters of antitank kinetic type ammunition
6.1 Necessary documentation for armaments and ammunitions assay……..
6.2 Methodology of elaboration and approbation of the assay and
evaluation of development plan …..……………………………………...
6.3 Methods and experimental investigation gear……………………………
6.4 Conclusions ………………………………………………………………...
Chapter 7 Finale conclusions
7.1 Conclusions concerning thesis theme.……………………………………
7.2 Personales contributions……………………….…………………………..
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Abstract
CHAPTER 1
INTRODUCTION
This paper, corporate than doctorate thesis, is organize in 7 (seven) chapters,
aiming one progressive, logical and argumentation of the problems propose
for study.
In the first subchapter is describe importance and actuality of the
chosen theme, to account for thus option of this topic.
Is indicate as well, the arguments which impose the mathematical modeling
for physical phenomenon of perforation armour by projectile, for surveying
thus evolution for characteristic parameters of this phenomenon.
Then, is detailed the manner for structure of the thesis in chapters.
CHAPTER 2
AT PRESENT STAGE CONCERNING THE
STUDY OF IMPACT PHENOMENON AMONG
PROJECTILE AND ARMOUR
In the first part of this chapter is describe and classified the modern
armours, whom technical and tactical characteristics enjoin ulterior
development for construction industry of perforating projectiles.
Then, is present one short historical evolution of the projection and
execution principles of the perforating kinetic type projectiles, whom
development was, is and will be permanently dependent for realizations of the
construction industry for armours of the battle machine. In continuance is
present one study concerning characteristics perforating armours phenomenon
towards antitank kinetic type ammunition.
Thus, basically, fundamentally problem of the perforating mechanics,
according to [21], may formulate in this manner :
Being given one impact body (projectile) and one target, each with
geometry, geometrical characteristics and specify materials characteristics,
after impact is necessary be determined :
-if target is perforate, the vestigial characteristics of the
projectile and target and the geometry dimensions of the orifice ;
- if target is not perforate, the geometry dimensions of the orifice.
Being definite adimensional parameter P, according to [48] :
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Abstract
P
p  p

b  b
(1)
- ρp is the material mass density of the projectile ;
- ρb is the material mass density of the armour ;
- σp is the material strength of the projectile ;
- σb is the material strength of the armour ;
is possible make classification of the manner how evolve the impact among
projectile and armour (fig.1), in function of the normal component at armour
surface, of the remaining velocity of projectile.
where :
Fig. 1 Domains of the perforation type
The next subchapter describe the manner for propagation of the strain
waves which appear so in projectile body how in armour mass.
Thus is relate calculus hypothesis of the resultant pressure at front of
the shock waves and which is propagate after impact, as and the phases
development in time of the perforation phenomenon.
In closure is present conclusions concerning at influence which the
important physical-mechanics parameters at perforation process, determine
evolution of this phenomenon so complex.
CHAPTER 3
MODERNE METHODS UTILIZE FOR
PERFORATING PARAMETERS CALCULUS
In the first subchapter is present the basic principles for mathematical
modeling of perforating phenomenon according to study hypothesis adopted.
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Abstract
Thus, at first, is describe the force system which characterize the
impact among projectile and armour, as and general physical theorems which
administer this phenomenon. Considering this, practical is possible to
determine, with assistant of the concordant mathematical algorithm, every
kinematic parameters of the projectile, before, concurrent and after the
process of perforation is make.
Then, is present sundries calculus relations for the strength force of
armour, adopted by researchers in domain, relations with an acceptable degree
of sublimation for physical phenomenon, validated by the experimental results,
which make possible an spanking determination for the perforation parameters
of the projectile, without utilize an complicated mathematical calculus.
Is describe sundries physical models for study of the perforation
phenomenon, through this being one original algorithm (model) propose by
author, with advantages and disadvantages each of this.
The model SD, propose by author, admit quickly determination for the
kinematic parameters of the perforating projectile, utilize unsophisticated
mathematical relations, the results obtained in this manner being different by
experimental results under 1%. This fact became possible on account of the
manner of formulation the energetic audit concerning at impact among
projectile and armour, utilize one correction function of energetic type,
dependent thus of impact velocity, which practically compensate sublimation
degree of phenomenon in the context of the adopted hypothesis
Thus, if we represent at same graphic the values of the maximum
thickness perforated by the projectile in function of impact velocity (fig.2),
analytical calculated H(vi)SD, and those resulted after the experiments H(vi)Exp,
it is pointed out the fact that the two curves practical superimpose each other on
common domain, irrespective of type and dimensions of perforating projectile
at study (in this case APFSDS-T).
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Abstract
THE COMPARATIVE VARIATION GRAPHIC
OF THE MAXIMUM PERFORATED THIKNESS
500
450
H [mm]
400
H(vi) SD
H(vi) Exp
350
300
250
200
1000
1200
1100
1400
1300
Vi [m/s]
Fig. 2 The comparative variation graphic of the maximum perforated thickness
Of course correction function utilize, F(vi), are characteristic variation
in function by type and dimensions of supposed projectile (fig. 3).
THE CORRECTION FUNCTION F(vi)
VARIATION GRAPHIC
APFSDS-T
2,5
F(vi)
2
1,5
1
0,5
0
0
200
400
600
800
vi [m/s]
1000
1200
1400
F(vi)
Fig. 3 The correction function F(vi) variation graphic
Because the impact phenomenon be supposed to specific bearing of the
body material which is in impact, be indicate also materials type models
used for armour perforation study and the manner for answer of these, in
dynamic operating.
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Abstract
Whereas perforation phenomenon is analyze than dynamic nonlinear
problem, which is characterize by loud sensibility in time of the geometric
characteristics (big distortions and displacements) and also by material
(plasticity, fracture, hardening or softening, phase transformations), is describe
some numerical models of analyze which utilize the finite element method (FEM).
The second subchapter show the modern methods of calculus for
perforation parameters, based at top soft which utilize the finite element
method and resolve operative, elegant and modern the fundamentally problem
of external ballistics and perforation mechanics.
Thus, determination of external ballistics parameters is possible utilizing
finite element method at external flowing of fluid mechanics problem, by
way COSMOS FloWorks program, [74].
In this situation, the modeling of the projectile must be execute with
accuracy because each structural detail, inclusive external surface roughness,
are one decisive influence about the flowing manner of air environs external
surface of this and accordingly in fixing of advancement resistance force value.
For terminal ballistics parameters, utilizing LS-DYNA program, [123],
with known the data concerning construction characteristics and material
property of the projectile and armour, is determine by way performing postprocessor, practically every parameters which define impact phenomenon.
In closure is present the conclusions which result by analysis of
impact phenomenon, utilizing modern methods of calculus for external
ballistics and terminal ballistics parameter.
Is dignify the fact that utilization of finite element method present one
performed algorithm, by future, with indubitable advantages to determination
and post-processing of theoretical results, which thus obtain, present too
approaching values from those determinate by experimental ways.
CHAPTER 4/5
CALCULUS OF PERFORATION PARAMETERS
Both chapters are same structure, the difference being in the type of
ammunition in study and namely : BR-412B in chapter 4 and APFSDS-T in
chapter 5.
The first subchapter present one succinct description of ammunition in
study, as and of this mechanic characteristics, which will be utilize ulterior
in the perforation parameters calculus.
Then is describe modern methods of calculus for the external ballistics
parameters, utilizing advanced soft in this domain.
Corresponding, is present the algorithm concerning determination of
terminal ballistics parameters by way of original model, propose by author.
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Abstract
In closure is considered the results obtained utilizing the specific soft
of the study domain and those determinate by experimental way, effectuating
comparisons between model SD data and those result utilizing LS-DYNA
program.
Certainly, the facility offered by post-processing module of this
program, situate this method in the top of those style of the domain.
CHAPTER 6
EXPERIMENTALE METHODS CONCERNING
DETERMINATION FOR PERFORATING
PARAMETERS OF ANTITANK KINETIC TYPE
AMMUNITIONS
This chapter begin with presentation of necessary documentation for
assay of armaments and ammunitions, following then one succinct description
of the major document from this category and namely : Assay and Evaluation
of Development Plan (AEDP).
The next subchapter describe the modality of experimental
determinations for major external and terminal ballistics parameters of the
kinetic type antitank ammunition, as and necessary gear for thus activity.
In closure is dignified the fact that whatever experimentation type,
which practically validate theoretical calculus, must be execute with rigorous
observance of the methodology, which regulate besides this type of activity
in all projection domains and especially with priority in the armaments and
ammunitions.
CHAPTER 7
FINALE CONCLUSIONS
This ultimate chapter present one series of appreciations concerning at
onset theme, which deepen some aspects less describe at speciality of the
domain, utilizing modern methods of study concerning at modality
determination of perforation parameters for antitank kinetic type projectiles.
The manner of presentation and utilization of these theoretical and
experimental research algorithms, with interpretations and contributions of the
author, improve and extend thus actual preoccupations in this domain.
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Abstract
Finally of this thesis, is presents personal contributions
concerning at vast and intricate domain of the armour
antitank kinetic type projectiles, contributions which will be
one on the first stair of the ulterior researches by engineers
of this especial domain, which is the fracture mechanics, whit
impact among projectile and armour.
of the author,
perforation by
constituting at
and specialists
applications at
*****
Key words : Projectile, armour plate, kinetic, velocity, target.
CURRICULUM VITAE
Name : DUMITRESCU
First name : ŞTEFAN
Date and place of birth : 23 January 1952 – GALAŢI.
Residence : GALATI – Ţiglina 3, Micro 17, str. Barboşi, nr. 51, bl. B3, ap. 47.
Phone : 0236/468152 ; 0723/911914.
Studies :
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THEORETICAL COLLEGE WITH MATRICULATION – GALAŢI,
series 1971 ;
MILITARY TECHNICAL ACADEMY – BUCUREŞTI;
Ward : mechanics engineers, series 1976 ;
CURS CAPACITATE POSTACADEMIC
Ward : engineers , series April 2000.
POST-GRADUATE MILITARY TECHNICAL ACADEMY –
BUCURESTI 01.11.2002;
Domain : mechanics engineering.
Engaged service :
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1976 – 1979 : lecturer – chief of didactic commission at Technical Chair
and the Artillery Shooting of Artillery Active Officer School “IOAN –
VODĂ” - SIBIU ;
1979 – 1981 : lecturer – chief of didactic commission at Engineers
Company of Reserve Officer School - BACĂU ;
1981 – 1992 : AQ Office Chief at Special Products Ward of S.C.
“AEROSTAR” S.A.- BACĂU;
1992 – 1995 : chief of Experienced Sector for Missile Technical at
Shooting Polygon SMÂRDAN – GALAŢI ;
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Abstract
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1995 – 2002 : engineer – chief at 343-rd Ward for Technical Military
Reparations – GALAŢI.
01.08.2002 : passed in reserve with allowance right, by means of
abolition 343-rd W.T.M.R.– GALAŢI
Received Medals and Decrees :
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Decree „MILITARY MERIT” 3-rd class – 20.09.1995;
Decree „MILITARY MERIT” 2-rd class – 27.12.1995 ;
Honorary Sign „IN SERVICE OF ARMY” – for Officers ;
01.12.2000.
Married ; 3 (three) child.
Civil Status :
Knowledge and deftness :
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projection and exploitation of mechanics systems ;
management and structure of the work place ;
auto license B+C, D+E from 1974 (at time 1981-1992 I perform
effective running in, special tests and check in counter for motor
vehicles of N.D.D.) ;
work at PC ;
foreign language – French :
 reading – very well ;
 speech – well ;
 writing – well.
electronics : audio and video systems ;
auto-mechanics and auto-electrics ;
mechanics processing at gear machine ;
montage and sustenance for sanitary installations.
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music ;
chess ;
pets and birds company.
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Hobby :
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