Modeling Of High Velocity Impact Research Articles

Numerical modeling of high velocity impact in sandwich panels with honeycomb core and composite skin including composite progressive damage model

In this paper, a numerical model is developed to simulate the ballistic impact of a projectile on a sandwich panel with honeycomb core and composite skin. To this end, a suitable material model for the aluminum honeycomb core is used taking the strain-rate dependent properties into account. To validate the ballistic impact of the projectile on the honeycomb core, numerical results are compared with the experimental results available in literature and ballistic limit velocities are predicted with good accuracy. Moreover, to achieve composite skin material model, a VUMAT subroutine including damage initiation based on Hashin’s seven failure criteria and damage evolution based on MLT approach modulus degradation is used. To validate the composite material model VUMAT subroutine, the ballistic limit velocities of the projectile impact on the composite laminates are predicted similar to the numerical results presented by other researchers. Next, the numerical model of the sandwich panel ballistic impact at different velocities is compared with the available experimental results in literature, and energy absorption capacity of the sandwich panel is predicted accurately. In addition, the numerical model simulated the sandwich panel damage mechanisms in different stages similar to empirical observations. Also, the composite skin damages are investigated based on different criteria damage contours.

Numerical modeling of high velocity impact applied to reinforced concrete panel

A numerical simulation of a high-velocity impact of reinforced concrete structures is a complex problem for which robust numerical models are required to predict the behavior of the experimental tests. This paper presents the implementation of a numerical model to predict the impact behavior of a reinforced concrete panel penetrated by a rigid ogive-nosed steel projectile. The concrete panel has dimensions of 675 mm × 675 mm × 200 mm, and is meshed using 8-node hexahedron solid elements. The behavior of the concrete panel is modeled using a Johnson-Holmquist damage model incorporating both the damage and residual material strength. The steel projectile has a small mass and a length of 152 mm, and is modeled as a rigid element. Damage and pressure contours are applied, and the kinetic and internal energies of the concrete and projectile are evaluated. We also evaluate the velocity at different points of the steel projectile and the concrete panel under an impact velocity of 540 m/s.

SPH modeling of high velocity impact into ballistic gelatin. Development of an axis-symmetrical formulation

ABSTRACTThe investigation of impact biomechanics is of extreme importance in the understanding of damages which are caused by a projectile impacting the human body. In a high-velocity impact framework, nonpenetrating impacts (nonlethal projectiles) or penetrating impacts can both lead to severe body trauma. An interesting way to study these phenomena is the numerical simulation, which can typically bring new information that cannot be accessed with experimental tests. Classical finite element is often used to simulate these kinds of complex problems. However, for perforating impacts, this method can rapidly lead to its limits, especially in terms of grid deterioration, when the projectile goes through the material. An alternative to this problem is to use a meshless method, like Smoothed Particles Hydrodynamics (SPH), which does not involve any mesh of the structure. Thus, the present study proposes to investigate perforating impact in a ballistic gelatin material, which is known as a good biological tissue simulant, using an axisymmetrical SPH code. Axisymmetrical formulation of the problem is developed, using appropriate numerical features such as contact procedure (between the projectile and the material), corrective factors.Experimental tests of the literature involving different impact velocities and different projectile sizes are replicated with the developed code, showing very promising results in terms of penetration and velocity of the projectile in the target.

Adaptive multi-scale modeling of high velocity impact on composite panels

A computationally efficient adaptive multi-scale methodology for modeling composites under high rates of loading is proposed. The physically based model relies on micromechanical properties of the constituents only. The adaptive algorithm switches between two different constitutive laws. Initially, the material response is calculated based on effective linear-elastic, orthotropic material properties at the ply scale which are calculated using the rule of mixtures. A modified Hashin–Rotem criterion is then used to identify the switch to a more accurate micromechanical analysis based on the generalized method of cells (GMC). The methodology is verified by simulating tensile tests on laminates with different stacking sequences. Finally the model validated against experimental data for high-velocity impact on quasi-isotropic composite targets taken from the literature in order to illustrate the efficiency and accuracy of the proposed methodology.

Impact comminution of solids due to local kinetic energy of high shear strain rate: I. Continuum theory and turbulence analogy

The modeling of high velocity impact into brittle or quasibrittle solids is hampered by the unavailability of a constitutive model capturing the effects of material comminution into very fine particles. The present objective is to develop such a model, usable in finite element programs. The comminution at very high strain rates can dissipate a large portion of the kinetic energy of an impacting missile. The spatial derivative of the energy dissipated by comminution gives a force resisting the penetration, which is superposed on the nodal forces obtained from the static constitutive model in a finite element program. The present theory is inspired partly by Grady's model for expansive comminution due to explosion inside a hollow sphere, and partly by analogy with turbulence. In high velocity turbulent flow, the energy dissipation rate gets enhanced by the formation of micro-vortices (eddies) which dissipate energy by viscous shear stress. Similarly, here it is assumed that the energy dissipation at fast deformation of a confined solid gets enhanced by the release of kinetic energy of the motion associated with a high-rate shear strain of forming particles. For simplicity, the shape of these particles in the plane of maximum shear rate is considered to be regular hexagons. The particle sizes are assumed to be distributed according to the Schuhmann power law. The condition that the rate of release of the local kinetic energy must be equal to the interface fracture energy yields a relation between the particle size, the shear strain rate, the fracture energy and the mass density. As one experimental justification, the present theory agrees with Grady's empirical observation that, in impact events, the average particle size is proportional to the (−2/3) power of the shear strain rate. The main characteristic of the comminution process is a dimensionless number Ba (Eq. (37)) representing the ratio of the local kinetic energy of shear strain rate to the maximum possible strain energy that can be stored in the same volume of material. It is shown that the kinetic energy release is proportional to the (2/3)-power of the shear strain rate, and that the dynamic comminution creates an apparent material viscosity inversely proportional to the (1/3)-power of that rate. After comminution, the interface fracture energy takes the role of interface friction, and it is pointed out that if the friction depends on the slip rate the aforementioned exponents would change. The effect of dynamic comminution can simply be taken into account by introducing the apparent viscosity into the material constitutive model, which is what is implemented in the paper that follows.

High velocity impact of metal sphere on thin metallic plate using smooth particle hydrodynamics (SPH) method

The modeling of high velocity impact is an important topic in impact engineering. Due to various constraints, experimental data are extremely limited. Therefore, detailed numerical simulation can be considered as a desirable alternative. However, the physical processes involved in the impact are very sophisticated; hence a practical and complete reproduction of the phenomena involves complicated numerical models. In this paper, we present a smoothed particle hydrodynamics (SPH) method to model two-dimensional impact of metal sphere on thin metallic plate. The simulations are applied to different materials (Aluminum, Lead and Steel); however the target and projectile are formed of similar metals. A wide range of velocities (300, 1000, 2000, and 3100 m/s) are considered in this study. The goal is to study the most sensitive input parameters (impact velocity and plate thickness) on the longitudinal extension of the projectile, penetration depth and damage crater.

Modeling of high velocity impact of spherical particles

Abstract A systematic analysis of a single copper particle impacting a semi-infinite copper substrate was carried out for initial impact velocities ranging between 100 m/s and 700 m/s by using the finite element method. Capability of and various issues related to: modeling in a Lagrangian reference frame; modeling using adaptive remeshing in an ALE reference frame; and, modeling considering material failure in a Lagrangian reference frame, are discussed. The Lagrangian approach with material failure is found effective in describing material behavior under high deformations and preventing excessive distortion of the mesh. It is found that at fast impact velocities the particle–substrate interface continuously undergoes shear failure as the particle penetrates into substrate. A lip which mostly contains failed material is formed as a result of localized deformation. Plastic deformation is confined to a small volume around the impact zone. Maximum strain is developed at the surface of particle and substrate. Compressive residual stresses are generated below the impact site after particle rebound, and higher impact velocities result in deeper compressive layers and somewhat larger stresses. A notable similarity in deformation patterns is observed between the impacts of 50 μm and 5 mm particles. Smaller particles are found to behave slightly stiffer than larger particles because of the strain-rate effects.

Some aspects on 3D numerical modeling of high velocity impact of particles in cold spraying by explicit finite element analysis

Three-dimensional modeling of particle impacting behavior in cold spraying by using ABAQUS/Explicit was conducted for copper and other materials. Various combinations of calculation settings concerning material damage, Arbitrary Lagrangian Eulerian adaptive meshing, distortion control and contact interaction were examined. The effects of meshing size and particle size on the impact behavior were analyzed compared to the previous results. The results show that the simulations with material damage cope well with the element excessive distortion and the resultant output is more reasonable than that obtained without material damage. In addition, the meshing size has less effect on the output with the material damage than without material damage. Although particle size has little effect on the morphologies of the deformed particles, it has some effect on the failure of elements at contact interfaces. The critical velocity for particle deposition could be estimated given the appropriate material properties.