Effects of spinning on residual velocity of ogive-nosed projectile undergoing ordnance velocity impact

Author(s):  
V Pranay ◽  
SK Panigrahi

In the present article, finite element analysis (FEA) based simulation on the study of the impact of projectiles having ogive nose shape has been made using ANSYS explicit dynamics. The effects of spinning on the residual velocity of ogive nosed projectile undergoing ordnance velocity impact have been presented. The variations of residual velocity due to different projectile materials and target plate thickness have been evaluated when the projectile is impacted by translational and spinning velocity. The target plates and ogive nosed projectile of a given material are discretized, and a rigorous error and convergence study has been made. Subsequently, the residual velocity of the considered model is evaluated by numerical techniques based on FEA. The results with the optimized meshed model are compared with the analytical results using the penetration theory and found that the results are well compared. Parametric study of the residual velocity has been made with varied ogive nosed materials and target plate thickness when the ogive nosed projectile undergoing ordnance velocity impact. Based on the numerical results, it has been found that the ogive nose projectile having tungsten alloy material is more effective undergoing ordnance velocity impact compared to steel 4340 material. For a given target plate thickness, spinning velocity, and impact velocity, the residual velocity is about 3 percent higher for the projectile made up of tungsten alloy compared to the steel 4340. The effects of the target plate thickness on the residual velocity of the ogive nose projectile do not seem to have much significant effects. It may be due to the simple reason that the ratio of the target plate thickness to projectile diameter is remaining within the intermediate range, i.e. within 1 and 10.

2016 ◽  
Vol 87 (16) ◽  
pp. 1938-1952 ◽  
Author(s):  
Chao Zhi ◽  
Hairu Long ◽  
Fengxin Sun

The aim of this research was to investigate the low-velocity impact properties of syntactic foam reinforced by warp-knitted spacer fabric (SF-WKSF). In order to discuss the effect of warp-knitted spacer fabric (WKSF) and hollow glass microballoon parameters on the impact performance of composites, eight different kinds of SF-WKSF samples were fabricated, including different WKSF surface layer structures, different spacer yarn diameters and inclination-angles, different microballoon types and contents. The low-velocity impact tests were carried out on an INSTRON 9250 HV drop-weight impact tester and the impact resistances of SF-WKSF were analyzed; it is indicated that most SF-WKSF specimens show higher peak impact force and major damage energy compared to neat syntactic foam. The results also demonstrate that the surface layer structure, inclination-angle of the spacer yarn and the volume fraction and type of microballoon have a significant influence on the low-impact performance of SF-WKSF. In addition, a finite element analysis finished with ANSYS/LS-DYNA and LS-PrePost was used to simulate the impact behaviors of SF-WKSF. The results of the finite element analysis are in agreement with the experimental results.


2019 ◽  
Vol 69 (6) ◽  
pp. 591-598 ◽  
Author(s):  
Chun Cheng ◽  
Zhonghua Du ◽  
Xi Chen ◽  
Lizhi Xu ◽  
Chengxin Du ◽  
...  

A smooth particle hydrodynamics (SPH) model was used to simulate the fragmentation process of the jacket during penetrator with lateral efficiency (PELE) penetrating the metal target plate to study the fragmentation characteristics of PELE jacket made of tungsten alloy. The validity of the SPH model was verified by experimental results. Then the SPH model was used to simulate the jacket fragmentation under different impact velocity and thickness of target plate. The influence of impact velocity and thickness of target plate on the jacket fragmentation was obtained by analysing the mass distribution and quantity distribution of the fragments formed by the jacket. The results show that the dynamic fragmentation of tungsten alloy can be simulated effectively using the SPH model, Johnson-Cook strength model, maximum tensile stress failure criterion and stochastic failure model. When the thickness of target plate is fixed, the greater the impact velocity, the greater the pressure produced by the projectile impacting the target plate; with the increase of impact velocity, the mass of residual projectile decreases, the number of fragments formed by fragmentation of jacket increases linearly, and the average mass of fragments decreases exponentially. When the impact velocity is constant, the greater the thickness of the target plate, the longer the pressure duration by the projectile impacting the target plate; with the increase of the thickness of target plate, the mass of residual projectile decreases, the number of fragments formed by fragmentation of jacket increases linearly, and the average mass of fragments decreases exponentially. The numerical calculation model and research method adopted in this paper can be used to study the impact fragmentation of solid materials effectively.


2018 ◽  
Vol 183 ◽  
pp. 02029
Author(s):  
Naoya Nishimura ◽  
Toshihiro Ito ◽  
Takeru Watanabe

Plate impact test on medium carbon steel were carried out to the target plate by impacting the flyer plate with one-third and two-thirds thickness of the target plate. The spall damage within the target plate was evaluated non-destructively with a low frequency scanning acoustic microscope as well as ultrasonic velocity and backscattering intensity. We observed the spall damage distribution by the B-and Cscan images. The distribution of spall damage through the plate thickness depends on the tensile stress area within the target plate. The difference of spall damage distribution was investigated by the plate impact test by flyer plate with different thickness. In the plate impact test by the flyer plate with 1/3 target plate thickness, the spall damage was generated by tensile stress area which superposed in the back surface side. On the other hand, in the case of 2/3 target plate thickness, the spall damage was detected at the impact surface side. By generating the spall damage in the different position through the target thickness, it will be possible to evaluate the accumulation of spall damage by reflection and transmission of the stress wave at the internal damage subjected to repeated impact.


2014 ◽  
Vol 564 ◽  
pp. 406-411
Author(s):  
Parnia Zakikhani ◽  
R. Zahari ◽  
Mohamed Thariq Hameed Sultan

Impact simulation with finite element analysis is an appropriate manner to reduce the cost and time taken to carry out an experimental testing on a component. In this study, the impact behavior of the composite hemispherical shell induced by low velocity impact is simulated in ABAQUS software with finite element method. To predict the responses of Kevlar fabric/polyester, glass fabric/polyester and carbon fabric/polyester in the form of a hemisphere, once as one layer and then as a three-layered composite under applied force by an anvil. The sequences of layers are changed, to investigate and compare the occurred alternations in the amount of energy absorption, impact force and specific energy absorption (SEA). The comparison of results showed that the highest and the lowest quantity of energy absorption and SEA belong to Carbon/Glass/Kevlar (CGK) and Kevlar/Carbon/Glass (KCG) respectively.


2020 ◽  
pp. 152808372097016
Author(s):  
Mithilesh Kumar Dewangan ◽  
SK Panigrahi

The present research deals with the finite element analysis (FEA) considering high strength Kevlar/epoxy composites as a target plate subjected to ballistic impact by varying nose-shaped projectiles. A multi-scale modelling technique has been implemented with FEA to design the intricate weave architecture. The damage properties are adopted using a user-defined function in the explicit analysis. The proposed methodology is validated by the available literature. The conical-shaped projectiles will have more damage and penetration as compared to the flat projectiles, which are studied for two plate thickness. The conical 60° and conical 90° projectiles will have better penetration to the target plate even for the increased thickness, whereas the Conical 120° and Flat projectiles will have a significant reduction in residual velocities. Also, with the increment in thickness, the energy absorption will significantly increase for Flat projectiles as compared to the conical projectiles. For lower velocities, the yarn slippage and puncturing are the major factors of failure along with fiber breakage and matrix cracking. As the velocities increased, the dominant phenomena of failure will be the linear momentum transfer.


Symmetry ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 776 ◽  
Author(s):  
Liangliang Ding ◽  
Wenhui Tang ◽  
Xianwen Ran ◽  
Zijian Fan ◽  
Weike Chen

With the increase of battlefield target diversity and protection mobility, the disadvantages of traditional armor piercing warheads have gradually become prominent. The conception of the PELE (penetration with enhanced lateral efficiency) projectile was thus proposed. The axial residual velocity of the projectile is a very important indicator of a PELE projectile, which mainly reflects the penetration ability of the PELE projectile. The PELE projectile is a symmetrical structure, so the collision problem can be simplified to plane collision. Furthermore, the two-dimensional plane is axisymmetric, and so it can be further simplified to one-dimensional collision. Based on simplification and assumptions, the mechanism of a PELE projectile penetrating a thin metal target plate was studied using the shock wave theory, and a theoretical model of axial residual velocity has been established in this article. The energy loss during the penetration process was divided into the following parts: the kinetic energy increment of the target plug in the impact region, the internal energy increment of the outer casing and inner core, and the shear energy dissipation of the projectile against the target plate. In addition, the specific methods of determining the energy loss of each part are given in detail. According to the conservation of energy, the approximate calculation formulae of the axial residual velocity of a PELE projectile have been deduced. Finally, the theoretical results were compared with the experimental results under different working conditions, and the results were in good agreement. Therefore, the theoretical model has application value and guiding significance in the field of engineering.


2021 ◽  
pp. 152808372199090
Author(s):  
Azizolrahman Amirian ◽  
Hossein Rahmani ◽  
Hossein Moeinkhah

In this paper, the high velocity impact (HVI) behavior of epoxy-based Kevlar-Basalt hybrid composites was studied experimentally and numerically. The composite specimens were manually placed in nine layers classified into six types of stacking sequences: non-hybrid, sandwich hybrid, and intercalated hybrid. The impact tests were conducted by using a ballistic apparatus at three different energy levels: 150 J, 200 J, and 250 J, and the amount of absorbed energy was calculated based on input velocity and residual velocity of the projectile. The results demonstrated that hybridization improves the behavior of composites in high velocity impacts compared to that of specimen that are not hybridized. The absorption of sandwich hybrids on average increased 23.25% and 11.3% compared to pure Basalt and Kevlar, respectively. Moreover, the intercalated hybrids showed an efficiency of about 35.6% and 21.76% better than that of pure Basalt and Kevlar, respectively, in absorbing energy. The same energy absorption pattern was observed in numerical simulation performed in ABAQUS/Explicit. Also, the highest amount of energy absorption and the lowest residual velocity as well as damage occurred when Kevlar was attacked by the projectile and the layers were intercalated.


2014 ◽  
Vol 566 ◽  
pp. 238-243
Author(s):  
Shinji Yoshie ◽  
Masatsugu Sakai ◽  
Tomoaki Murakami ◽  
Kazuo Fujimoto

The speed record for a ground transportation train is held by a linear motor car, whose running speed exceeds 500 km/h. The possibility of collision with animals, generally birds, is a hazard. Thus, materials that are both lightweight and high-strength have become the ideal candidates for the front cover on bullet trains. Before studying the high-velocity impact behaviors of the candidate materials, we gathered some reference data by implementing a high-velocity impact using the aluminum alloy that was used in the testing of bird impacts on airplanes, and selected the A6061-T6 plate. The soft body was fabricated using 1.25 kg of gelatin with a collision cross section of φ100 mm; the maximum collision velocity in the tests was 550 km/h, and the target plate had dimensions of 500 × 500 × 3 mm. The plate was tested with and without a fixed peripheral part, and the results of these boundary conditions were compared. Strain gauges were attached to the backside of the plate to try to acquire the distribution of the strain history. The test specimens were prepared from a plate from the same lot, and tensile tests at a static strain rate (10-5/s), a medium strain rate (0.1–20/s), and a high strain rate (100–1000/s) were conducted. The data for the constitutive laws of the numerical analysis were acquired and analyzed. The results of the experiment and the analysis of the strain history of the area neighboring the impact point were compared and discussed. A main conclusion of the experiment is that the target plate with a fixed peripheral part was not penetrated when the velocity was 550 km/h, and the residual displacement did not exceed approximately 60 mm. The strain energy on the dynamic characteristics to uniform elongation becomes effective in a decision for failure of a target material.


Author(s):  
Hussein Dalfi

Advanced composite laminates (i.e. glass composite laminates) are highly susceptible to low velocity impact, and the induced damage failures substantially reduced their residual mechanical properties and safe-service life during their application. Therefore, experiments and simulation efforts to predict their low-velocity impact damages and energy absorbing have significant importance in composite structures design. In this regards, experimental and finite element analysis (FEA) with aiding Abaqus software were respectively performed to investigate the influence of yarn hybridisation on the response of composite laminates under low velocity impact. The hybrid yarns, which consisted of S-glass and polypropylene yarns have been used to manufacture two types of composites; non-crimp cross-ply hybrid yarns and twill hybrid fabric composites. Additionally, for comparison, the non-crimp cross-ply and twill fabric composite laminates have been made from glass fibres only. The vacuum infusion resin process has been adopted to manufacture these composite laminates. The impact performance of composite laminates has been investigated using low-velocity impact at 15 J, 35, and 50 impact energy levels. The numerical analysis was executed using Abaqus/Explicit and Hashin failure criteria and continuum damage mechanics by using homogenous shell were adopted to simulate the intra-laminar damage in layers. Meanwhile, standard cohesive inter-laminar interfaces that inserted between composite layers with quadratic stress failure criteria have been used to model delamination failures. The numerical results regarding impact force-time, displacement–time and energy-time histories plots, as well as the damage evolution behaviour of matrix crack and fibre fracture, presented an agreement with experimental results.


2015 ◽  
Vol 12 (19) ◽  
pp. 5871-5883 ◽  
Author(s):  
L. A. Melbourne ◽  
J. Griffin ◽  
D. N. Schmidt ◽  
E. J. Rayfield

Abstract. Coralline algae are important habitat formers found on all rocky shores. While the impact of future ocean acidification on the physiological performance of the species has been well studied, little research has focused on potential changes in structural integrity in response to climate change. A previous study using 2-D Finite Element Analysis (FEA) suggested increased vulnerability to fracture (by wave action or boring) in algae grown under high CO2 conditions. To assess how realistically 2-D simplified models represent structural performance, a series of increasingly biologically accurate 3-D FE models that represent different aspects of coralline algal growth were developed. Simplified geometric 3-D models of the genus Lithothamnion were compared to models created from computed tomography (CT) scan data of the same genus. The biologically accurate model and the simplified geometric model representing individual cells had similar average stresses and stress distributions, emphasising the importance of the cell walls in dissipating the stress throughout the structure. In contrast models without the accurate representation of the cell geometry resulted in larger stress and strain results. Our more complex 3-D model reiterated the potential of climate change to diminish the structural integrity of the organism. This suggests that under future environmental conditions the weakening of the coralline algal skeleton along with increased external pressures (wave and bioerosion) may negatively influence the ability for coralline algae to maintain a habitat able to sustain high levels of biodiversity.


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