Introduction to High velocity impact Analysis
High-velocity impact analysis is a field of study that focuses on understanding and predicting the behavior of materials and structures when subjected to extremely rapid and intense impacts. It plays a crucial role in various industries, including aerospace, automotive, defense, and structural engineering. The importance of high-velocity impact analysis lies in its ability to assess the performance and safety of structures and components under extreme loading conditions. By simulating and analyzing the effects of high-speed impacts, engineers can evaluate the structural integrity, energy absorption capabilities, and potential failure modes of materials and systems. This information is vital for designing robust structures that can withstand impact events such as collisions, explosions, or projectile impacts.
High-velocity impact analysis also aids in the development of protective measures and safety standards. It enables engineers to optimize the design of armor systems, ballistic protection, and crashworthy structures, ensuring the highest level of safety for personnel and assets. Additionally, this analysis supports the advancement of materials and manufacturing techniques, as it provides valuable insights into material response, deformation, and failure mechanisms.
Workshop 1: High-velocity impact simulation to a ceramic plate reinforced with steel plate in Abaqus
This tutorial provides a comprehensive explanation of the high-velocity impact of a steel projectile onto a ceramic plate that has been reinforced with steel, using Abaqus software. Both the steel projectile and steel plate are represented as deformable components, and a material model incorporating ductile and shear damage with progressive damage evolution is employed. Similarly, the Silicon plate incorporates ductile damage with evolution, Drucker-Prager plasticity with hardening, and the Us-Up equation to determine the fracture zone. The dynamic explicit procedure is deemed suitable for this type of analysis. In the load module, fixed boundary conditions are applied to the plates, and an initial velocity is assigned to the projectile. It is important to note that the quality of the mesh at the impact zone greatly influences the results.
Workshop 2 : High velocity bullet impact simulation to the concrete wall
This tutorial provides a detailed demonstration of a high-speed impact on a concrete wall using Abaqus software. The bullet is represented as a Lagrangian part, and the JHC material model is employed to simulate the behavior of the concrete under the impact. Throughout the analysis, the bullet penetrates the concrete wall, resulting in significant damage.
Workshop 3: High velocity impact simulation to fluid-filled containers utilizing FEM with adaptive coupling to SPH
This tutorial showcases a numerical investigation into the simulation of projectile impacts on a container filled with fluid. All components are represented as three-dimensional parts, with the projectile modeled using steel material and the container using aluminum. Johnson-Cook plasticity and damage models are employed to forecast damage propagation in both metal parts. The water inside the container is modeled using the Us-Up equation of state, and a Smoothed Particle Hydrodynamics (SPH) model is utilized to predict its behavior. The explicit procedure is deemed suitable for analyzing high-velocity impacts.
Workshop 4: Bullet impact simulation to the three-layered plate
This tutorial explores the investigation of high-velocity bullet impact on a three-layered plate. The modeling of the entire structure was done in a three-dimensional space. Different damage and plasticity models were employed to accurately represent the behavior of steel, aluminum, and silicon carbide. Specifically, ductile and shear damage with evolution were used for modeling steel, Johnson-Cook damage and plasticity were employed for aluminum, and ductile damage coupled with Drucker-Prager plasticity were utilized for silicon carbide. The dynamic explicit procedure was deemed suitable for conducting this type of analysis. Adequate interaction and boundary conditions were applied to all components.
Workshop 5: High-velocity impact simulation with Johnson–Holmquist model to a ceramic target
This tutorial focuses on the simulation of the high-velocity impact of a ceramic target using the Johnson-Holmquist material model. Ceramic materials are commonly employed in armor protection applications. Over the years, Johnson, Holmquist, and their colleagues have developed constitutive relations to simulate the behavior of ceramics when subjected to large strain, high-strain rate, and high-pressure impact conditions. In this particular case, the JHB and JH-2 material models are investigated to analyze the penetration velocity of a gold projectile striking a silicon carbide target. The computed results are compared with previously published findings by Holmquist and Johnson. The target material, silicon carbide, is exceptionally hard and primarily used in compressive load situations, with limited ability to withstand tension. It finds applications in bulletproof vests and car brakes due to its high durability. The material’s strength is influenced by pressure, and in high-speed impact scenarios, damage to the material significantly affects its strength evolution. When silicon carbide is completely failed, it cannot sustain any load. On the other hand, the projectile is made of gold, which is comparatively soft compared to the target material.
Both the projectile and target are described using the Lagrangian approach. In all three cases, general contact with surface erosion is implemented. The analysis takes into account element deletion and node erosion. Specifically, the JH-2 model is utilized. Unlike the JHB model, the JH-2 model assumes that the damage variable progressively increases as plastic deformation occurs. In other words, according to the JH-2 model, the damage variable gradually grows alongside plastic deformation.
Workshop 6: Impact simulation on Granite stone
The constitutive relationship of a material is not just a summary of experimental data; it also plays a crucial role in numerical simulations. It aims to accurately represent the physical and mechanical properties of materials, thereby improving the accuracy of simulation results. As the demand for numerical simulations increases, various constitutive models for materials are constantly being developed and optimized. For materials subjected to large strains, high strain rates, and high pressures (LHH), dynamic constitutive models tend to involve more complex parameters, including physical properties and sensitive coefficients such as rate effects and strength coefficients. Consequently, determining these parameters has become increasingly challenging.
The JH-2 constitutive model was initially designed to simulate the behavior of brittle materials, particularly ceramics. It incorporates softening characteristics and includes pressure-dependent strength, damage, fracture, significant strength after fracture, bulking, and strain-rate effects.
The JH-2 model assumes that the strength of both intact and fractured material relies on pressure, strain rate, and damage. The relationship between strength and these parameters is defined by a set of constants derived from standard measurements conducted under dynamic and quasi-static conditions.
In this simulation, the high-velocity impact of a rigid projectile on granite stone is investigated. An explicit step is employed with a general contact method, considering internal damage and erosion through the use of an inp file. Throughout the analysis, the damage variable for granite is prominently observed.
Workshop 7: Impact simulation to aluminum honeycomb sandwich panels
Sandwich panels are extensively utilized in lightweight construction, particularly in the aerospace industry, due to their high specific strengths and stiffness. Throughout the service life of a sandwich panel, impacts are expected to occur from various sources. For example, debris can be propelled at high velocities during aircraft takeoffs and landings, tools may accidentally drop on the structure during maintenance, or collisions with birds can happen. While visual inspection may reveal minimal damage on the outer facesheet of the sandwich panel, significant damage can occur within the impacted region between the facesheet and the core. This damage can lead to a reduction in structural stiffness and strength, which can further propagate under additional loading. Consequently, there has been an increasing focus on understanding the behavior of sandwich panels under impact.
Finite element modeling is a popular and cost-effective approach employed in the study of sandwich structures. To achieve computational efficiency, the core of sandwich structures, which consists of a large number of cells, is often replaced with an equivalent continuum model. Analysis of sandwich panels is then conducted based on their effective properties rather than considering the intricate cellular structure. Several experimental and analytical techniques have been proposed to predict the effective continuum properties of the core, taking into account its geometric and material characteristics. Researchers have modified the classical laminate theory and applied it to a unit cell to derive the equivalent elastic rigidities for honeycomb cores. However, deriving the theoretical formulation for effective elastic constants of the core can be complex or even impossible if the sandwich construction is highly intricate. Even if it is feasible, the mathematical derivations for one type of sandwich core may not be applicable to other types.
In this simulation, the projectile is represented as a three-dimensional component made of steel material, while the honeycomb structure with two facial sheets is modeled as a three-dimensional shell using aluminum material. Both bodies are characterized by the application of Johnson-Cook plasticity and damage models. The dynamic explicit procedure is deemed suitable for conducting this type of analysis. The contact between the honeycomb and facial sheets is assumed to be perfect, while the contact between the projectile and the upper surface involves surface-to-surface interaction with contact properties. Due to the high initial velocity of the projectile, noticeable deformation and damage occur on the sandwich panel, and the Johnson-Cook damage parameter becomes available for examination after the impact.
You can watch demo here.
Workshop 8: High-velocity impact simulation to reinforced concrete panel
This tutorial focuses on investigating the numerical simulation modeling of high-velocity impact on a reinforced concrete panel. It is well-known that concrete exhibits higher strength in compression compared to tension. To enhance its tensile strength, concrete elements are reinforced with materials capable of withstanding tensile loads.
Concrete materials experience both static and dynamic loads. Static loads are permanent, while dynamic loads vary over time. Impact loads, which can have catastrophic consequences on structures, fall under the category of dynamic loads. Therefore, analyzing the impact behavior of reinforced concrete (RC) structures has garnered significant attention in recent decades.
This tutorial specifically examines the impact behavior of a reinforced concrete panel penetrated by a rigid steel ogive-nosed projectile through numerical simulation. To model the concrete material, the Johnson-Holmquist damage model (JH-2) is employed.
Various constitutive models have been utilized to describe the dynamic behavior of brittle materials subjected to impact loads. In this study, the Johnson Holmquist damage model (JH-2) is employed to analyze the impact behavior of a reinforced concrete panel that is penetrated by a steel ogive nosed projectile. The JH-2 model is an improved version of the Johnson-Holmquist (JH-1) ceramic model, specifically designed to simulate the impact behavior of brittle materials. It accounts for factors such as dilatation, pressure-strength dependence, and strain-rate effects resulting from damage.
The concrete material is represented as a three-dimensional part, the beam is modeled as a wire, and the bullet is considered a rigid part. The dynamic explicit procedure is deemed suitable for this type of analysis. A general contact approach is implemented, considering nodal erosion through the utilization of an input file. The concrete part is assigned fixed and symmetric boundaries, while the bullet is given an initial velocity. A fine mesh is necessary at the contact zone between the two parts. After the simulation, the damage parameter and stress can be obtained for further analysis.
Workshop 9: High-velocity impact simulation of a brass projectile to the Aluminum-ceramic-glass fiber
This tutorial focuses on investigating the simulation of high-velocity impact. Specifically, the impact of a brass projectile on a layered structure composed of Ceramic-Aluminum-Glass fiber is examined. In the simulation, the brass projectile, ceramic plate, aluminum plate, and epoxy-glass layers are represented as three-dimensional components.
The material properties and behavior are modeled differently for each component in the simulation. The brass material is represented as an elastic material with Johnson-Cook plasticity and damage model. The ceramic material is modeled using the Beissel model with elastic data, incorporating fail stress and Hashin failure criteria. The epoxy-glass layers are also considered with Hashin’s damage criterion.
For the analysis, the dynamic explicit step is deemed suitable. However, the Abaqus CAE lacks the ability to consider erosion and internal elements’ failure. To address this limitation, the input file capability is utilized to define internal damage and erosion. The contact between components is defined as general contact in the input file.
Boundary conditions are defined for the plates, with fixed conditions around them. The projectile is assigned an initial velocity of 550m/s. It is important to have a fine mesh, especially in the contact zone, to obtain accurate results during visualization.
After the simulation, various results such as stress, strain, damage, and plastic strain can be obtained for further analysis.
Workshop 10: High- velocity impact simulation of the steel projectile on the composite panel (Steel-Concrete-Epoxy glass)
This tutorial focuses on investigating the simulation of high-velocity impact. Specifically, it explores the impact of a steel projectile on a composite panel consisting of Steel-Concrete-Epoxy glass layers. In the simulation, the steel projectile is represented as a cylindrical solid part. The first layer of the panel, which is made of steel, is modeled as a three-dimensional component. The middle plate, composed of concrete, is also represented as a three-dimensional solid part. The composite layers are modeled as three-dimensional parts using the continuum shell technique. Additionally, the beam part is modeled as a wire part in the simulation.
In this study, the steel material is utilized to model both the projectile and the first layer of the panel, considering its elastic-plastic behavior. Ductile and shear damage criteria are employed to predict damage propagation and failure in these components. The epoxy-glass lamina is modeled with elastic behavior and fail stress. Hashin’s damage criterion with damage evolution is used to account for damage in the composite layers. For the high-velocity impact on concrete, the JH2 material model is employed, which accurately calculates damage and failure in brittle materials.
The simulation employs a dynamic explicit step along with a general contact procedure. The contact between the steel plate and concrete, as well as between concrete and the first layer of the composite, is assumed to be perfect. Cohesive interaction based on the cohesive surface is used as the contact property with damage data among the composite layers. The beam part is embedded within the concrete host. Symmetry boundaries are applied to the symmetry surfaces, while fixed boundaries are assigned to the sides of the panel. The steel projectile is given an initial velocity. It is important to have a fine mesh to ensure accurate results.
After the simulation, all relevant results such as stress, strain, damage parameters, and failure can be obtained for further analysis.
Workshop 11: High-velocity aluminum projectile oblique impact simulation to the silicon-carbide target
This tutorial focuses on investigating the simulation of oblique high-velocity impact. Specifically, it examines the impact of an aluminum rod on a silicon-carbide target. In the simulation, the silicon-carbide target is represented as a three-dimensional solid part, while the aluminum projectile is modeled as another three-dimensional solid part.
The investigation of the interaction between two colliding bodies, referred to as impact dynamics or terminal ballistics, holds significant importance in various applications. One such application is the study of bullet impact on armor. Understanding the deformation behavior of materials under impact loading is crucial for designing improved products and, more importantly, for saving lives. Knowledge about material response to impact loading aids in estimating, enhancing, and prolonging the lifespan and performance of structures. The dynamics of impact primarily depend on two key variables: the geometry and material properties of the colliding bodies.
When metals are subjected to applied loading, their response is influenced not only by strain but also by parameters like temperature, pressure, and strain rate. The Johnson-Cook (JC) model is a widely used phenomenological model for predicting the material response of metals under high strain rate and impact loading. In this study, the JC plasticity and damage model is employed to simulate the behavior of the aluminum projectile. Ceramic materials, on the other hand, are inherently brittle. They possess high compressive strength but low tensile strength, and tend to experience progressive damage under compressive loads due to the development of microfractures.
For this type of analysis, the dynamic explicit step is deemed appropriate. However, due to internal failure, the conventional surface-to-surface contact method is not effective. Instead, the input file capability is utilized to define a contact that considers erosion during the impact. The symmetry boundary is applied to the symmetry zones, and an initial velocity is assigned to the aluminum projectile. It is crucial to have a fine mesh, especially around the contact zone, to obtain accurate results.
After the simulation, various results such as stress, strain, damage, ductile damage, failure, and others can be obtained for further analysis.
It would be helpful to see Abaqus Documentation to understand how it would be hard to start an Abaqus simulation without any Abaqus tutorial.
Christopher –
With these tutorials, I can accurately analyze and predict the behavior of materials and structures under high-velocity impacts. This information can be highly useful in designing safer and more resilient systems. As an engineer, I have personally utilized these tutorials and achieved highly effective results. I highly recommend this package to anyone seeking high-velocity impact simulation.
Experts Of CAE Assistant Group –
Thanks for valued review,Christopher!