Impact of a non-homogeneous sphere on a rigid surface

2004 ◽  
Vol 218 (3) ◽  
pp. 273-281 ◽  
Author(s):  
M J Carré ◽  
D M James ◽  
S J Haake
Keyword(s):  
Oblique Impact ◽  
Dynamic Force ◽  
Rigid Surface ◽  
Normal Impact ◽  
Homogeneous Sphere ◽  
Static Test ◽  
Cricket Ball ◽  
Oblique Impacts ◽  
The Impact ◽  
Good Agreement

This paper examines the impact behaviour of a non-homogenous sphere (in this case a cricket ball with a rolled core construction) with a rigid surface. Experiments were carried out to measure the force-deflection behaviour of a cricket ball during a normal impact in two orientations (impacting on the seam and perpendicular to the seam). For the two orientations of impact, a disparity was found in terms of the force-deflection behaviour. Greater deformation was found for impacts landing on the seam, compared to those landing perpendicular to the seam. Comparisons with quasi-static test data suggested that only the bottom third of the ball may have been compressed during impact. The dynamic force-deflection behaviour was modelled using a mass attached to a Hertzian spring in parallel with a damper whose damping coefficient varied with the contact area. The coefficients in the model could be described using the velocity before impact alone. The model was found to be in good agreement with the experimental data. The model was then extended to predict oblique impacts by incorporating a measured coefficient of friction. This performed well in predicting the rebound velocity, angle and spin of a cricket ball after oblique impact with a cricket pitch. Inconsistencies in the results were attributed to deformation in the pitch surface.

A Study for Evaluating Local Damage to RC Panels Subjected to Oblique Impact: Part 1 — A Study for Evaluating Local Damage Caused by Oblique Impact of Rigid Projectiles

2017 ◽  
Author(s):  
Yoshimi Ohta ◽  
Akemi Nishida ◽  
Haruji Tsubota ◽  
Yinsheng Li
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structures ◽  
Oblique Impact ◽  
Reinforced Concrete Structures ◽  
Local Damage ◽  
Normal Impact ◽  
Impact Tests ◽  
Oblique Impacts ◽  
New Formula ◽  
The Impact

Many empirical formulae have been proposed to evaluate the local damage to reinforced concrete structures caused by the impact of rigid projectiles. Most of these formulae have been derived based on impact tests perpendicular to the target structures. To date, few impact tests oblique to the target structures have been conducted. The purpose of this study is to propose a new formula for evaluating the local damage caused by oblique impacts based on experiments and simulations. The new formula is derived by modifying an empirical formulation for normal impact and the agreement with results of past oblique impact tests is discussed.

The penetration and ricochet of ogive-nosed rigid projectiles obliquely impacting metallic targets

2021 ◽  
pp. 204141962110377
Author(s):  
Yaniv Vayig ◽  
Zvi Rosenberg
Keyword(s):  
Experimental Data ◽  
Numerical Simulations ◽  
Dynamic Pressure ◽  
Oblique Impacts ◽  
Simulation Results ◽  
The Impact ◽  
Penetration Depths ◽  
Resistance To Penetration ◽  
Good Agreement

A large number of 3D numerical simulations were performed in order to follow the trajectory changes of rigid CRH3 ogive-nosed projectiles, impacting semi-infinite metallic targets at various obliquities. These trajectory changes are shown to be related to the threshold ricochet angles of the projectile/target pairs. These threshold angles are the impact obliquities where the projectiles end up moving in a path parallel to the target’s face. They were found to depend on a non-dimensional entity which is equal to the ratio between the target’s resistance to penetration and the dynamic pressure exerted by the projectile upon impact. Good agreement was obtained by comparing simulation results for these trajectory changes with experimental data from several published works. In addition, numerically-based relations were derived for the penetration depths of these ogive-nosed projectiles at oblique impacts, which are shown to agree with the simulation results.

Evaluation of Local Damage to Reinforced Concrete Panels Subjected to Oblique Impact of Rigid and Soft Missiles

2018 ◽  
Author(s):  
Akemi Nishida ◽  
Minoru Nagai ◽  
Haruji Tsubota ◽  
Yinsheng Li
Keyword(s):  
Reinforced Concrete ◽  
Simulation Method ◽  
Impact Angle ◽  
Oblique Impact ◽  
Local Damage ◽  
Empirical Formulas ◽  
Rc Structures ◽  
Impact Tests ◽  
Oblique Impacts ◽  
The Impact

Many empirical formulas have been proposed for evaluating local damage to reinforced concrete (RC) structures caused by impacts of rigid missiles. Most of these formulas have been derived based on impact tests normal to the target structures. Up to now, few impact tests oblique to the target structures have been carried out. This study has been conducted with the purpose of proposing a new formula for evaluating the local damage caused by oblique impacts based on previous experimental and simulation results. In this paper, the results of simulation analyses for evaluating the local damage to a RC panel subjected to normal and oblique impacts by rigid and soft missiles, by using the simulation method that was validated using the results of previous impact experiments. Based on the results of these simulation analyses, the effects of the rigidity of the missile as well as the impact angle on the local damage to the target structures are clarified.

A Study for Evaluating Local Damage to Reinforced Concrete Panels Subjected to Oblique Impact: Part 2 — Simulation Analysis of the Experimental Results of Local Damage Caused by Impact of Deformable Projectiles

2017 ◽  
Author(s):  
Akemi Nishida ◽  
Yoshimi Ohta ◽  
Haruji Tsubota ◽  
Yinsheng Li
Keyword(s):  
Reinforced Concrete ◽  
Simulation Analysis ◽  
Impact Load ◽  
Oblique Impact ◽  
Local Damage ◽  
Impact Tests ◽  
Rigid Projectile ◽  
Oblique Impacts ◽  
Simulation Results ◽  
The Impact

Many empirical formulae have been proposed for evaluating the local damage to reinforced concrete structures caused by rigid projectile impact. Most of these formulae are based on impact tests perpendicular to the target structures. To date, few impact tests oblique to the target structures have been conducted. In this study, we aim to obtain a new formula for evaluating the local damage caused by oblique impacts based on previous experimental and simulation results. We analyze and simulate the local damage owing to impact by deformable projectiles. The experimental and simulation results were in good agreement and confirmed the validity of the proposed analytical method. Furthermore, the internal energy of the deformable projectile absorbed upon impact was approximately 60% of the total energy. In comparison to a rigid projectile, it is possible to reduce the impact load and consequently the damage to the target.

scholarly journals Approximate methods for calculating the impact of a massive body on a plate lying on the base

2021 ◽  
Vol 2131 (3) ◽  
pp. 032083
Author(s):  
S A Rukhlenko
Keyword(s):  
Infinite Plate ◽  
Elastic Base ◽  
Ideal Incompressible Fluid ◽  
Normal Impact ◽  
Rigid Plastic ◽  
Approximate Methods ◽  
Plastic Deformations ◽  
Set Up ◽  
The Impact ◽  
Good Agreement

Abstract Normal impact of a massive body on a uniformly stretched plate lying on the base is investigated. A hinged round or rectangular plate on an elastic base, or an infinite plate on the surface of an ideal incompressible fluid is considered. The solution to the elastoplastic impact is in good agreement with numerical calculations and experimental data. With a small parameter of elastic collapse, that is, with the developed local plastic deformations, a solution to the problem of impact with rigid-plastic local collapse can be used. Approximate formulas for calculating the main characteristics of rigid-plastic impact are set up.

Spin generation during an oblique impact of a compliant ball on a non-compliant surface

2011 ◽  
Vol 226 (2) ◽  
pp. 86-95 ◽  
Author(s):  
Tom Allen ◽  
James Ibbitson ◽  
Steve Haake
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Element Model ◽  
Oblique Impact ◽  
Tennis Ball ◽  
Compliant Surface ◽  
Oblique Impacts ◽  
Impact Characteristics ◽  
The Impact ◽  
The Finite Element Model

Oblique impacts between a ball and surface are a key part of many sports. Previous work has shown that a ball can slide, over-spin or roll at the end of an impact, depending on impact conditions. Inbound spin ratio was analysed to determine if it could be used to identify what is likely to happen at the end of impact for all sports regardless of surface, ball type, impact velocity, angle and spin. A predictive model, in the form of a finite element model, of a tennis ball was validated against experimental data for oblique impacts with inbound spin ratios in the range of –1 to 1. Spin ratio is defined as the product of the ball’s angular velocity and radius divided by the centre of mass velocity tangential to the surface. The finite element model was then used to determine the effect of impact conditions and ball parameters on outbound spin ratio. The study showed that for constant inbound spin ratio, outbound spin ratio was dependent on inbound velocity and angle. For constant inbound velocity and angle, decreasing the mass and increasing the stiffness of the ball through a change in material properties resulted in an increase in the maximum outbound spin ratio. Inbound spin ratio can be used to predict how a ball will rebound from a surface; however, inbound velocity and angle must be constant. Spin ratio can therefore be used to compare the impact characteristics for different ball and surface scenarios.

Re-Examination of NHTSA’s Research Moving Deformable Barrier Front Oblique Impacts With Vehicle to Vehicle Crashes Using FE Models

2013 ◽  
Author(s):  
Bavneet S. Brar ◽  
Ravi Tangirala
Keyword(s):  
Structural Response ◽  
Deformation Mode ◽  
Oblique Impact ◽  
Car Model ◽  
Vehicle To Vehicle ◽  
Oblique Impacts ◽  
Simulated Field ◽  
Moving Deformable Barrier ◽  
Impact Simulations ◽  
The Impact

The objective of this study is to investigate how the target vehicle’s structural response to NHTSA’s Research Moving Deformable Barrier (RMDB), during oblique impact conditions, compares with actual vehicle to vehicle impacts. It tabulates vehicle kinematics, deformation mode and structural intrusions for both the simulated field accident situations, with a SUV and a small car bullet vehicles, onto a small car target vehicle. These parameters are then compared with those resulting from the RMDB impact simulations. The differences are highlighted and quantified. The effects of the bullet vehicles variation in impact speed were also investigated. The paper details sensitivity of the RMDB’s Principle Direction of Force by varying the impact overlap percentage. Lastly, further modifications to the RMDB have been suggested to improve its vehicle to vehicle relevance. The FE models used in this research were a full vehicle, restraints and occupant integrated small car model along with a midsized SUV simulation model.

An approach towards the projectile trajectory during the oblique Steinheim meteorite impact by the interpretation of structural crater features and the distribution of shatter cones

2017 ◽  
Vol 155 (1) ◽  
pp. 193-202 ◽  
Author(s):  
E. BUCHNER
Keyword(s):  
Structural Features ◽  
Oblique Impact ◽  
Meteorite Impact ◽  
Central European ◽  
Eastern Segment ◽  
The Asymmetry ◽  
Shatter Cones ◽  
The Impact ◽  
Impact Experiments ◽  
Good Agreement

AbstractThe distinct alignment of the Steinheim Basin and the Nördlinger Ries impact structures in SW Germany and the Central European tektite strewn field suggest ENE-directed trajectories of the Ries and Steinheim impacting bodies. From impact experiments, the asymmetry of the Steinheim crater and the arrangement of structural features therein are in good agreement with features produced during an oblique impact at 30° from the horizontal. The restriction of shatter cones to the eastern segment of the Steinheim Basin crater also suggests a west–east-directed trend of the impact direction, and supports previous models that favoured such impactor trajectory.

Fractal Characterization of Slurry Eroded Surfaces at Different Impact Angles

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
Abouel-Kasem ◽  
M. A. Al-Bukhaiti ◽  
K. M. Emara ◽  
S. M. Ahmed
Keyword(s):  
Erosion Rate ◽  
Impact Angle ◽  
Oblique Impact ◽  
Slurry Erosion ◽  
Normal Impact ◽  
Power Spectral ◽  
Impact Angles ◽  
The Impact ◽  
The Relationship

In the present work, the topographical images of slurry erosion surfaces at different impact angles were quantified using fractal analysis. The study showed that the variation of fractal value of slope of linearized power spectral density with the impact angle is largely similar to the relationship between the erosion rate and the impact angle. Both the fractal value and erosion rate were maximum at 45 deg and 90 deg for ductile and brittle materials, respectively. It was found also that the variation of fractal values versus the impact angle has a general trend that does not depend on magnification factor. The fractal features to the eroded surfaces along different directions showed high directionality at oblique impact angle and were symmetrical at normal impact.

scholarly journals Ballistic Behavior of Oblique Ceramic Composite Structure against Long-Rod Tungsten Projectiles

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 2946 ◽  
Author(s):  
Luo ◽  
Wang ◽  
Wang ◽  
Cheng ◽  
Zhu
Keyword(s):  
Silicon Carbide ◽  
Layer Structure ◽  
Oblique Impact ◽  
Residual Energy ◽  
Normal Impact ◽  
Ballistic Performance ◽  
Impact Location ◽  
Long Rod ◽  
Armor Steel ◽  
The Impact

Oblique ceramic armor structure composed of an oblique part and a backing part was designed to resist the ballistic impact of long rod penetrators. The front part consisted of an oblique silicon carbide ceramic and a triangular titanium alloy prism. The backing part contained layered silicon carbide and armor steel designed to absorb the residual energy of penetrators. The structure’s response to penetration was examined experimentally by considering different impact locations on oblique targets. Numerical simulations of the experiments were performed to reproduce the penetration and failure processes that occurred in the armor modules. In addition, a simple layer structure with the identical line-of-sight thickness of each material used in the oblique impact was simulated under a normal impact. The rod and target performances with the oblique impact and normal impact were compared and analyzed in detail. The results showed that the oblique structure had a better ballistic performance as a result of an extra short dwell period before penetrating the ceramic in comparison with the normal layer case. The ability of the oblique targets to defeat long rod projectiles differed with the impact location on the ceramic. The present study paves the way for ceramic armor obliquity applications.

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