Dynamic Stress Analysis of a Composite Electromagnetic Track
The firing of an electromagnetic gun is shown to result in the armature moving along the guide rail, which can cause extrusion, wear, planing and other problems, which set limits on its application. The track properties can be adjusted by changing its composition, so as to obtain good electrical con...
Saved in:
| Published in: | Проблемы прочности |
|---|---|
| Date: | 2018 |
| Main Authors: | , , , |
| Format: | Article |
| Language: | English |
| Published: |
Інститут проблем міцності ім. Г.С. Писаренко НАН України
2018
|
| Subjects: | |
| Online Access: | https://nasplib.isofts.kiev.ua/handle/123456789/173993 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| Journal Title: | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| Cite this: | Dynamic Stress Analysis of a Composite Electromagnetic Track / Z.G. Tian, X.Y. An, Y. Yang, L.K. Zhao // Проблемы прочности. — 2018. — № 5. — С. 66-75. — Бібліогр.: 15 назв. — англ. |
Institution
Digital Library of Periodicals of National Academy of Sciences of Ukraine| id |
nasplib_isofts_kiev_ua-123456789-173993 |
|---|---|
| record_format |
dspace |
| spelling |
Tian, Z.G. An, X.Y. Yang, Y. Zhao, L.K. 2020-12-28T18:45:41Z 2020-12-28T18:45:41Z 2018 Dynamic Stress Analysis of a Composite Electromagnetic Track / Z.G. Tian, X.Y. An, Y. Yang, L.K. Zhao // Проблемы прочности. — 2018. — № 5. — С. 66-75. — Бібліогр.: 15 назв. — англ. 0556-171X https://nasplib.isofts.kiev.ua/handle/123456789/173993 539.4 The firing of an electromagnetic gun is shown to result in the armature moving along the guide rail, which can cause extrusion, wear, planing and other problems, which set limits on its application. The track properties can be adjusted by changing its composition, so as to obtain good electrical conductivity, corrosive resistance, and strength. For simplicity, the composite track is presented as an elastic foundation beam, and the general solution of composite track deflection at dynamic load is obtained by using the two-dimensional Fourier integral transformation, on this basis, the bending moment distribution and expression for dynamic stress are obtained. The characteristics of dynamic stress distribution and factors that influence them are analyzed, the effect of the proportion of the composite layer and its parameters on the dynamic stress of the track is discussed. Показано, что выстрел электромагнитной пушки приводит к перемещению брони по направляющей, что может вызывать выталкивание, износ, обдирание и другие процессы, которые налагают ограничения на ее применение. Свойства направляющей могут быть модифицированы путем изменения ее состава, что обеспечит хорошую удельную электропроводность, коррозионную стойкость и прочность. Для простоты композиционная направляющая представлена в виде упругой фундаментной балки, общее решение для прогиба направляющей при динамической нагрузке получают с помощью двухмерного интегрального преобразования Фурье, на его основании получают распределение изгибающего момента и выражение для напряжения при динамической нагрузке. Выполнен анализ характеристик распределения напряжений и влияющих на них факторов. Рассмотрено влияние доли композиционного слоя и его параметров на напряжение направляющей при динамической нагрузке. en Інститут проблем міцності ім. Г.С. Писаренко НАН України Проблемы прочности Научно-технический раздел Dynamic Stress Analysis of a Composite Electromagnetic Track Анализ напряжений при динамической нагрузке композиционной электромагнитной направляющей Article published earlier |
| institution |
Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| collection |
DSpace DC |
| title |
Dynamic Stress Analysis of a Composite Electromagnetic Track |
| spellingShingle |
Dynamic Stress Analysis of a Composite Electromagnetic Track Tian, Z.G. An, X.Y. Yang, Y. Zhao, L.K. Научно-технический раздел |
| title_short |
Dynamic Stress Analysis of a Composite Electromagnetic Track |
| title_full |
Dynamic Stress Analysis of a Composite Electromagnetic Track |
| title_fullStr |
Dynamic Stress Analysis of a Composite Electromagnetic Track |
| title_full_unstemmed |
Dynamic Stress Analysis of a Composite Electromagnetic Track |
| title_sort |
dynamic stress analysis of a composite electromagnetic track |
| author |
Tian, Z.G. An, X.Y. Yang, Y. Zhao, L.K. |
| author_facet |
Tian, Z.G. An, X.Y. Yang, Y. Zhao, L.K. |
| topic |
Научно-технический раздел |
| topic_facet |
Научно-технический раздел |
| publishDate |
2018 |
| language |
English |
| container_title |
Проблемы прочности |
| publisher |
Інститут проблем міцності ім. Г.С. Писаренко НАН України |
| format |
Article |
| title_alt |
Анализ напряжений при динамической нагрузке композиционной электромагнитной направляющей |
| description |
The firing of an electromagnetic gun is shown to result in the armature moving along the guide rail, which can cause extrusion, wear, planing and other problems, which set limits on its application. The track properties can be adjusted by changing its composition, so as to obtain good electrical conductivity, corrosive resistance, and strength. For simplicity, the composite track is presented as an elastic foundation beam, and the general solution of composite track deflection at dynamic load is obtained by using the two-dimensional Fourier integral transformation, on this basis, the bending moment distribution and expression for dynamic stress are obtained. The characteristics of dynamic stress distribution and factors that influence them are analyzed, the effect of the proportion of the composite layer and its parameters on the dynamic stress of the track is discussed.
Показано, что выстрел электромагнитной пушки приводит к перемещению брони по направляющей, что может вызывать выталкивание, износ, обдирание и другие процессы, которые налагают ограничения на ее применение. Свойства направляющей могут быть модифицированы путем изменения ее состава, что обеспечит хорошую удельную электропроводность, коррозионную стойкость и прочность. Для простоты композиционная направляющая представлена в виде упругой фундаментной балки, общее решение для прогиба направляющей при динамической нагрузке получают с помощью двухмерного интегрального преобразования Фурье, на его основании получают распределение изгибающего момента и выражение для напряжения при динамической нагрузке. Выполнен анализ характеристик распределения напряжений и влияющих на них факторов. Рассмотрено влияние доли композиционного слоя и его параметров на напряжение направляющей при динамической нагрузке.
|
| issn |
0556-171X |
| url |
https://nasplib.isofts.kiev.ua/handle/123456789/173993 |
| citation_txt |
Dynamic Stress Analysis of a Composite Electromagnetic Track / Z.G. Tian, X.Y. An, Y. Yang, L.K. Zhao // Проблемы прочности. — 2018. — № 5. — С. 66-75. — Бібліогр.: 15 назв. — англ. |
| work_keys_str_mv |
AT tianzg dynamicstressanalysisofacompositeelectromagnetictrack AT anxy dynamicstressanalysisofacompositeelectromagnetictrack AT yangy dynamicstressanalysisofacompositeelectromagnetictrack AT zhaolk dynamicstressanalysisofacompositeelectromagnetictrack AT tianzg analiznaprâženiipridinamičeskoinagruzkekompozicionnoiélektromagnitnoinapravlâûŝei AT anxy analiznaprâženiipridinamičeskoinagruzkekompozicionnoiélektromagnitnoinapravlâûŝei AT yangy analiznaprâženiipridinamičeskoinagruzkekompozicionnoiélektromagnitnoinapravlâûŝei AT zhaolk analiznaprâženiipridinamičeskoinagruzkekompozicionnoiélektromagnitnoinapravlâûŝei |
| first_indexed |
2025-11-26T00:08:46Z |
| last_indexed |
2025-11-26T00:08:46Z |
| _version_ |
1850593340285779968 |
| fulltext |
UDC 539.4
Dynamic Stress Analysis of a Composite Electromagnetic Track
Z. G. Tian,
1
X. Y. An, Y. Yang, and L. K. Zhao
Key Laboratory of Mechanical Reliability for Heavy Equipments and Large Structures of Hebei
Province, Yanshan University, Qinhuangdao, China
1 tianzhenguo1@163.com
The firing of an electromagnetic gun is shown to result in the armature moving along the guide rail,
which can cause extrusion, wear, planing and other problems, which set limits on its application. The
track properties can be adjusted by changing its composition, so as to obtain good electrical
conductivity, corrosive resistance, and strength. For simplicity, the composite track is presented as
an elastic foundation beam, and the general solution of composite track deflection at dynamic load is
obtained by using the two-dimensional Fourier integral transformation, on this basis, the bending
moment distribution and expression for dynamic stress are obtained. The characteristics of dynamic
stress distribution and factors that influence them are analyzed, the effect of the proportion of the
composite layer and its parameters on the dynamic stress of the track is discussed.
Keywords: composite track, dynamic stress, Fourier transform, dynamic load, elastic
foundation beam.
Introduction. The electromagnetic gun can obtain higher speed than the traditional
launching mode [1] and can save energy and reduce reaction time. However, some
problems which are difficult to overcome hinder its practical application [2, 3], such as the
ablation in the track, the stability of the launching process, the electrical conductivity and
the stiffness support [4]. In order to realize the high power of the electromagnetic railgun
and can be repeatedly fired, on the one hand, people are exploring the structural form of the
composite track, for example, the excellent physical properties of carbon nanotube
reinforced copper matrix composites make it a suitable composite material for composite
track [5], in addition, Ti2AlN is a very comprehensive performance of the copper-based
composite material, can make the material with high strength, high elastic modulus and
high conductivity, but also an optional composite material of the launch track [6]. On the
other hand, it can provide theoretical basis for the design of the track by calculating the
dynamic response and stress distribution of the track and analyzing its stress and
deformation [7–11]. In [12], the guide rail is simplified as an elastic foundation beam, and
the influence of the length of the guide rail on the resonance velocity is discussed under the
assumption that the armature passes through the guide rail at a constant speed. The effects
of plasma viscosity and inertia resistance on the armature motion are analyzed by numerical
simulation [13]. In [14], the characteristics of the recoil motion of the electromagnetic rail
gun are analyzed, and the recoil motion curve under certain conditions is obtained.
However, these studies do not take into account the effects of armature forces on the track
and the characteristics of the armature’s variable accelerating motion, the study on the
dynamic response of composite track is rare. When the current flows into the composite
guide rail, the armature will be subjected to a strong thrust and accelerates the motion along
the guide rail. From the distribution of electromagnetic fields between the composite track
and the current intensity of the armature, the thrust of the armature is obtained, and the
equation of motion of the armature is obtained. By calculating the repulsive force of the
interaction between the guide rails and the expansion of the armature caused by the Joule
heating, the value of the moving load and its variation law can be obtained. Considering the
© Z. G. TIAN, X. Y. AN, Y. YANG, L.K. ZHAO, 2018
66 ISSN 0556-171X. Ïðîáëåìè ì³öíîñò³, 2018, ¹ 5
structure of the electromagnetic gun launcher, the control equation of the composite track
simplified as the elastic foundation beam is transformed, and the dynamic response
equation of the composite track is obtained, on this basis, the expressions of the dynamic
moment and dynamic stress of composite track are obtained. By an example, the influence
of the material ratio of the composite track and the parameters of the access voltage on the
dynamic stress of the composite track is analyzed, which provides the theoretical basis for
the design of the composite track.
1. Control Equation of Composite Track. As illustrated in Fig. 1, when an
electromagnetic railgun is fired, the high current is charged into the track, the current forms
a strong magnetic field between the tracks, the armature sliding along the track at high
speed under the action of thrust, at the same time, the track is subject to repulsion, the
thermal expansion of the armature and rail due to Joule heat will also be limited, thus, the
armature will give a pressure to the track. Considering the effect of the external structure of
the track on the track, the composite track at the launching state can be simplified to an
elastic foundation beam, as shown in Fig. 2. The intensity of repulsive forces between
tracks is q t1 ( ), the pressure of the armature on the track is P t( ), l t( ) is the distance of the
t moment armature along the track, and a is the length of the armature along the track.
The dynamic governing equation of the composite track is [15]
( )
( , )
( , )
( , )
( ,E I E I
w y t
y
kw y t hd
w y t
t
q y1 1 2 2
4
4
2
2
� � � �
�
�
�
�
�
t ), (1)
where w y t( , ) is the deflection of the track, k is the elastic coefficient of the foundation,
� is the average mass density of the composite track, E I1 1 is the flexural rigidity of the
basic track, E I2 2 is the flexural rigidity of the composite layer, E1 and E2 are,
respectively, the elastic modulus of the base material and the composite layer material,
h h h� �1 2 is the thickness of composite track, h1 and h2 are, respectively, the thickness
of the basic track and composite layer track, d is the height of the track, q y t( , ) is the load
acting on the inside of the track, q y t q t H y l t q t H a y l t( , ) ( )[ ( ( ))] ( ) [ ( ( )) ]� � � � � �1 2
2 21 ,
q t P t a2 ( ) ( )� is the average pressure concentration of the armature acting on the track,
and H x l t( ( ))� and H a x l t[ ( ( )) ]2 2
� � are Heaviside step functions.
ISSN 0556-171X. Ïðîáëåìè ì³öíîñò³, 2018, ¹ 5 67
Dynamic Stress Analysis of a Composite ...
Fig. 1. Schematic of composite rail launcher.
2. Dynamic Response of Composite Track. By Eq. (1), the application of two-
dimensional Fourier transform and inverse transform can be used to get the deflection of
the rail is as follows:
w y t
q e d d
E I E I k hd
j y t
( , )
( , )
( )
( )
�
� � �
�
1
4 2
1 1 2 2
4
�
� �
� �
�
2
,
�
�
�� (2)
where
q q t H y l t H q t H a y l t e j( , ) ( )[ ( ( ))] ( ) [ ( ( )) ]� � � � � � �
�
1 2
2 21 ( ) ,� y t dydt�
�
�
�� (3)
� and are integral variables, and j� �1 is a pure imaginary. Formula (3) is
introduced into Eq. (2), and the deflection expression of the rail along the composite track
is obtained
w y t
q e d d
E I E I k hd
j y l
( , )
( )
( )
( ( ))
�
� � �
�
1
4 2
1
1 1 2 2
4
�
� � �
� �
� �
( ( ))l
t
�
2
0
���
�
�
� � �
�
1
2 2
2
1 1 2 2
4
�
� �
� �
sin( ) ( )
[( )
( ( ))a q t e d
E I E I k hd
ja y l t
( ( )) ]
.
l t a2
�
�
� (4)
The average concentration of the repulsive force of the interaction between the two
tracks is [8]
q t
i t
l t
l t h b
h b
1
0
2 2
2
2
28
1( )
( )
( )
( ) ( )
,��
� �
�
�
�
�
�
�
�
�
�
�
�
(5)
where i t( ) is the current intensity of the incoming track base layer and b is the distance
between tracks.
Assuming that both sides of the track limit the thermal expansion of the armature, the
average temperature along the z direction is used as the basis for calculating the armature
strain, the average concentration of the load on the track is
q t
Q t d E da T
a a
2
2
24
6
( )
( )
,� �
�
�
�
�
�
�
� �
(6)
68 ISSN 0556-171X. Ïðîáëåìè ì³öíîñò³, 2018, ¹ 5
Z. G. Tian, X. Y. An, Y. Yang, and L.K. Zhao
Fig. 2. Schematic of the load state of the composite track.
where Q t i t h d a( ) ( ) ( )�
2
1
2 2
� is the Joule heat source power density of armature, Ea is
the elastic modulus of the armature, �T is the coefficient of thermal expansion of the
armature, � a is the thermal conductivity of the armature, and �a is the thermal diffusion
coefficient of the armature. The formula (5) and (6) are introduced into Eq. (4), and the
dynamic response of the track can be obtained after integration.
3. The Dynamic Stress of Composite Track. Figure 3 is a cross-sectional view of
one side composite track, �z is the neutral axis of the cross section, c is the distance from
the inner surface of the track to the neutral axis. According to the equilibrium equation of
the section and the properties of the planar graph, the formula of c is obtained as follows:
c
E h E h E hh
E h E h
�
� �
�
2 2
2
1 1
2
1 1
2 2 1 1
2
2( )
. (7)
The approximate differential equation of the deflection curve of the composite track is
d w
dy
M y
E I E I
2
2
1 1 2 2
�
�
( )
. (8)
If the influence of rail shear force is neglected, the track is in the pure bending state,
the normal stress on the cross section of the track is
�
�
y
y
E M y x
E I E I
E M y x
E I E I
1
1
1 1 2 2
2
2
1 1 2 2
�
�
�
�
�
�
�
�
�
�
�
�
( )
,
( )
,
�
(9)
where I1 and I 2 are, respectively, the inertia moment of the base layer and track
composite layer to the neutral axis, and � y1 and � y2 are, respectively, the normal stresses
in the y-axis direction on the cross section of the track base and the track composite layer,
At this point, the normal stress on the cross section of the composite track is obtained by
Eqs. (4), (8), and (9).
4. Analysis of Examples.
4.1. Theoretical Analysis. The composite track base layer is made of copper, and the
composite layer is made of steel, the track length is 2 m, the thickness of the track base
layer is h1 30� mm, the thickness of the composite layer is h2 10� mm, the distance
between the two tracks is b� 20 mm, the mass density of copper is �1 8900� kg/m3, the
ISSN 0556-171X. Ïðîáëåìè ì³öíîñò³, 2018, ¹ 5 69
Dynamic Stress Analysis of a Composite ...
Fig. 3. The cross section of composite track.
elastic modulus is E1 115� GPa, Poisson’s ratio is �1 � 0.33, and conductivity is �1 �
� �5 88 107. ( )��
�m 1. The mass density of steel is �2 7850� kg/m3, the elastic modulus is
E2 210� GPa, Poisson’s ratio is � 2 � 0.3, conductivity is � 2
69 93 10� �. ( )��
�m 1, and
the initial resistance is R0 0 01� . .� The length of the aluminum armature in the direction
of the guide rail is a� 20 mm, the thickness and height of armature both are 20 mm,
conductivity is � a � �3 6 107. ( )��
�m 1, the mass density is �a � 2700 kg/m3, the thermal
conductivity is � a � 237 W/(m C�� ), the expansion coefficient is �T � �
�2 35 10 5. �
�C 1,
and the exothermic surface coefficient is �a � 500 W/(m C�� ). The system discharge
current is i0 50� kA, the vacuum permeability is �0
61 256 10� �
�. H/m, and the elastic
coefficient of the foundation is k � 10 GPa.
When the thickness ratio of the track is h h2 1 1 3� : , the normal stress � y of ��x
��22.6, 7.4, and 17.4 mm on the section of y� 0.8 m is changed with the armature
moving distance l t( ), as shown in Fig. 4, it can be calculated by Eq. (5) at this time that
c� 17.4 mm, thus, the three curves are the normal stress on the outer surface of the track,
the normal stress at the interface of the track, and the normal stress on the inner surface of
the track. It can be seen that when the armature passes through the y� 0.8 m, the normal
stress reaches the maximum value, the stress on the inner surface of the track is the largest,
and the extreme value is the tensile stress, and the stress of the outer surface of the track is
the compressive stress, the value is smaller than the absolute value of the inner surface
stress, and the stress at the interface of the track is relatively small, because it is closer to
the neutral axis. This explains why the inner surface of the rail is more vulnerable to
damage.
The curves of the inner surface normal stress in y direction with the moving distance
of the armature is shown in Fig. 5, when the track thickness is h� 40 mm, and the track
thickness ratio is different. It can be seen that with the increase of the thickness of the
composite layer, the normal stress increases, the maximum value of the stress is increased
by about 31%. The curves of the inner surface normal stress in the y direction at y� 0.8,
1.0, and 1.2 m with the moving distance of the armature is shown in Fig. 6, when the track
thickness ratio is h h2 1 1 7� : , as can be seen in the Fig. 6, when the armature through the
location, the stress of the location appears extreme value, and in the position earlier or later
when the stress is negative, when the armature slides in other locations on the track, the
position of the analysis will also have an impact, but the absolute value of the stress caused
by it than the armature through this position caused by the stress is much smaller.
The curves of the inner surface normal stress in y direction at y� 0.8 m with the
moving distance of the armature is shown in Fig. 7, when the track thickness ratio is
70 ISSN 0556-171X. Ïðîáëåìè ì³öíîñò³, 2018, ¹ 5
Z. G. Tian, X. Y. An, Y. Yang, and L.K. Zhao
Fig. 4. Variation of � y at 0.8 m of track versus the armature moving distance l t( ).
h h2 1 1 7� : , and the elastic coefficients of foundation are k � 10, 15, and 20 GPa,
respectively, it can be seen that increasing the external constraint of the track, that is,
increasing the elasticity coefficient of the foundation can effectively reduce the stress peak
of the inner surface of the track.
The curves of the inner surface normal stress in the y direction at y� 0.8 m with the
moving distance of the armature is shown in Fig. 8, when the track thickness ratio is h h2 1 �
� 1 7: , and the thermal expansion coefficient of armature material are �T � �
�2 35 10 5. ,
3 35 10 5. ,�
� and 4 35 10 5. �
�
�
�C 1, respectively, as can be seen from the Fig. 8, with the
increase of the thermal expansion coefficient of the armature material, the stress on the
inner surface of the track is increased, the maximum value of the stress is increased by
about 45%, which can be understood that the temperature rise of the armature is the same
under the same launching conditions, however, due to the increase of the coefficient of
thermal expansion of the armature, the expansion of the armature along the y-direction
increases, which results in an increase in the force acting on the track, therefore, reducing
the thermal expansion coefficient of the armature material can reduce the stress of the
railgun at launching state.
ISSN 0556-171X. Ïðîáëåìè ì³öíîñò³, 2018, ¹ 5 71
Dynamic Stress Analysis of a Composite ...
Fig. 5 Fig. 6
Fig. 5. The curves of the inner surface stress � y with l t( ) changes when the track thickness ratio is
different.
Fig. 6. The relationship between the inner surface stress � y and l t( ) at the different position of the
track.
Fig. 7 Fig. 8
Fig. 7. The curves of the internal surface stress � y with l t( ) changes when the elasticity coefficient
of the foundation is different.
Fig. 8. The curves of the inner surface stress � y with l t( ) changes when the thermal expansion
coefficient of the armature material is different.
4.2. Numerical Simulation Analysis. In order to analyze the stress state of the
composite track from different angles, the Comsol software is used to simulate the
multiphysics field of the railgun. The geometric parameters and material properties are
consistent with the theoretical calculation.
Figure 9 shows the distribution of the normal stress � y of the track when the
armature is moved to y� 1m, it is shown that the stress on the orbit around the armature is
larger than that of the other position, the distribution law is consistent with the theoretical
results, but the absolute value of the stress peak is larger than the theoretical calculation
result, mainly because the theoretical calculation does not take into account the “rigid”
effect of the armature on the track.
Figure 10 shows the normal stress � y distribution on the different longitudinal faces
x��20,�30, and � 40 mm of the track when the armature moves to y� 1 m. Figure 10
shows that the more close to the inner surface of the track, the more significant the role of
armature, in comparison with Fig. 4, it can be found that the closer the position to the outer
surface of the track, the closer the simulation results are to the theoretical results, because
the “rigid ” effect of the armature on the track is weakened as the depth increases.
72 ISSN 0556-171X. Ïðîáëåìè ì³öíîñò³, 2018, ¹ 5
Z. G. Tian, X. Y. An, Y. Yang, and L.K. Zhao
Fig. 9. Nephogram of stress � y distribution at launching state.
Fig. 10. Nephogram of stress � y distribution on different surfaces of the base layer.
Figure 11 shows the distribution of the temperature of the armature when the armature
is moved to y� 1 m, it can be seen that the temperature at the end of the armature in the
contact surface between the armature and the track is the highest, and the middle position is
lower, the maximum temperature is about three times the minimum internal temperature,
this is due to the uneven distribution of current density caused by current flow effect.
ISSN 0556-171X. Ïðîáëåìè ì³öíîñò³, 2018, ¹ 5 73
Dynamic Stress Analysis of a Composite ...
Fig. 11. Temperature nephogram of the armature.
y �1000 mm y �1005 mm
y �1010 mm y �1015 mm
Fig. 12. Temperature nephogram in different faces of the armature.
Figure 12 shows the temperature distribution on the armature along the y-direction
cross sections y� 1000, 1005, 1010, and 1015 mm, respectively, it can be seen from the
observation that the temperature at the adjacent launch end is higher and the temperature on
the outlet side is relatively low, the maximum temperature is close to 1400�C, which causes
the local thermal expansion of armature to increase, resulting in the increase of local
pressure on the track, causing the track local stress to rise sharply, resulting in track
damage. This is mainly due to the roundabout flow phenomenon, and the current density
distribution in Fig. 13 illustrates this. The distribution of the current density is uniform at
the front of the launching end of the electromagnetic gun, in the vicinity of the armature,
the distribution of current density is uneven, especially in the vicinity of the interface of the
track and armature, and the concentration of current density is apparent.
Conclusions. Theoretical and numerical results show that the thermal expansion of
the armature caused by the electrothermal effect is the main factor leading to the
deformation and failure of the track, the roundabout flow phenomenon causes the armature
current density to be concentrated when the current flow from the track to the armature, so
that the pressure in the vicinity of the end point of the armature and the rail contact surface
is increased, resulting in a sharp increase in the stress on the inner surface of the local rail.
The calculation results show that when the thermal expansion coefficient of the
armature increases by 86%, the tensile stress of the inner surface of the rail is increased by
45%, therefore, reducing the coefficient of thermal expansion and controlling the expansion
of the armature is an effective way to minimize the damage of the track under the same
launching conditions. The thickness of the composite layer and the stiffness of the external
support of the track influence the dynamic stress of the track when the stiffness of the
external support is doubled, the stress on the inner surface can be reduced by about 33%.
The material with high conductivity, high strength, and low thermal expansion
coefficient can be used to improve the overall strength of the composite track, at the same
time, taking into account the rail conductivity and the overall stiffness of the track, to select
a reasonable proportion of the thickness of the composite layer.
Acknowledgments. This work is supported by Natural Science Foundation of Hebei
Province (A2015203086).
1. H. D. Fair, “The past, present, and future of electromagnetic launch technology and
the IEEE international EML symposia,” IEEE T. Plasma Sci., 41, No. 5, 1024–1027
(2013).
2. H. D. Fair, “Advances in electromagnetic launch science andtechnology and its
applications,” IEEE T. Magn., 44, No. 1, 225–230 (2009).
3. I. R. Mcnab and F. C. Beach, “Naval railguns,” IEEE T. Magn., 43, No. 1, 463–468
(2007).
74 ISSN 0556-171X. Ïðîáëåìè ì³öíîñò³, 2018, ¹ 5
Z. G. Tian, X. Y. An, Y. Yang, and L.K. Zhao
Fig. 13. The current density nephogram of armature and track at launching state.
4. B. Lei, R. G. Zhu, Q. Zhang, et al., “Production features and research status of
gouging in electromagnetic railgun,” Ordn. Mater. Sci. Eng., 34, No. 3, 76–80 (2011).
(in Chinese)
5. K. H. W. Kenneth, Z. A. Martin, L. H. Jeffery, et al., “The effect of carbon nanotube
aspect ratio and loading on the elastic modulus of electrospun poly(vinyl alcohol)-
carbon nanotube hybrid fibers,” Carbon, 47, No. 11, 2571–2578 (2009).
6. W. Wang, Z. Zhan, Q. Tang, et al., “Interfacial reaction and properties of Ti2AlN-
La2O3/Cu composite,” Rare Metal Mater. Eng., 44, No. 5, 1177–1180 (2015). (in
Chinese)
7. C. Fan and W. Wang, “Review on the electromagnetic railgun,” J. Yanshan Univ., 31,
No. 5, 377–386 (2007).
8. Z. G. Tian, X. Z. Bai, and Y. Yang, “Dynamic response of rail during launch process
of electromagnetic rail,” J. Vib. Shock, 31, No. 2, 10–14 (2012).
9. C. Wei, Y. Xu, and Y. Y. Ma, “Study on damage of composite material barrel under
transient impact load,” J. Ordn. Equip. Eng., 37, No. 7, 131–136 (2016). (in Chinese)
10. Z. G. Tian, X. Y. Meng, X. Y. An, et al., “Dynamic response of composite rail during
launch process of electromagnetic railgun,” ACTA Armamentarii, 38, No. 4, 651–657
(2017). (in Chinese)
11. Z. G. Tian and X. Y. An, “Multi physical field coupling analysis of composite
electromagnetic track,” J. Gun Launch & Control, 38, No. 3, 1–6 (2017). (in Chinese)
12. J. T. Tzeng and W. Sun, “Dynamic response of cantilevered rail guns attributed to
projectile/gun interaction-theory,” IEEE T. Magn., 43, No. 1, 207–213 (2007).
13. Y. Yang and J. X. Wang, “Numerical modeling and analysis on EM gun firing
principle,” J. Gun Launch & Control, 4, 9–13 (2008). (in Chinese)
14. J. Shi and B. M. Li, “Research on recoil process of electromagnetic railgun,” ACTA
Armamentarii, 36, No. 2, 227–233 (2015). (in Chinese)
15. W. P. Xie and G. Wang, “Analysis of dynamic characteristics of rail system induced
by moving load,” J. Zhengzhou Univ., 24, No. 1, 24–27 (2003). (in Chinese)
Received 05. 03. 2018
ISSN 0556-171X. Ïðîáëåìè ì³öíîñò³, 2018, ¹ 5 75
Dynamic Stress Analysis of a Composite ...
|