Johnson-Cook Failure Model Research Articles

Optimal prediction and validation of Johnson-Cook failure model for Al 6061 using genetic algorithm

Optimal prediction and validation of Johnson-Cook failure model for Al 6061 using genetic algorithm

Experimental Determination and Simulation Validation: Johnson–Cook Model Parameters and Grinding Simulation of 06Cr18Ni11Ti Stainless Steel Welds

Hydrogen permeation resistance in the welded region of 06Cr18Ni11Ti steel is relatively weak due to surface defects, which need high integrity surface machining. The parameters of the welding material for 06Cr18Ni11Ti steel are currently unavailable, which causes some inconvenience for simulation studies. To fill the lack of 06Cr18Ni11Ti steel weld material parameters in the relevant literature at the present stage, the quasi-static tensile test at different strain rates and notch specimen tensile tests were conducted in this paper and determined the Johnson–Cook (J-C) constitutive model parameters and Johnson–Cook failure model parameters. Subsequently, a multi-grain grinding simulation model was built based on W-M fractal dimension theory by using the determined material parameters. The influence of processing parameters on grinding heat was analyzed. Grinding experiments were conducted to analyze the influence of processing parameters on grinding heat and grinding force. By comparing the simulation and experimental results, it is revealed that the average error is 9.37%, indicating relatively small discrepancy. It is demonstrated that the grinding simulation model built in this paper could efficiently simulate the grinding process, and the determined weld material parameters of 06Cr18Ni11Ti steel have been verified to possess high accuracy and reliability.

Effectiveness of thermoviscoplastic material models in predicting the thermomechanical behavior of rolled homogenous armor steel

This paper studies the dynamic and elevated temperature behavior of rolled homogeneous armor steel, which is crucial for applications such as blast, impact, crash, and ballistic resistance. The deformation behavior is analyzed through tensile tests. The tensile tests of RHA steel are conducted at quasi-static 10−4s−1≤εṗ≤10−1s−1 to dynamic 10−1s−1≤εṗ≤36.439s−1 strain-rates and at high temperatures ranging from room temperature (RT,27°C) to 500°C. Phenomenological Johnson-Cook (JC) models and semi-physical Rusinek-Klepaczko (RK) material models are employed in finite element (FE) simulations of tensile tests. The JC failure model, with a small modification, is used along with the material models to simulate the loss of load-bearing capacity of the component. All necessary material parameters are extracted from the test data. The material models and the damage model are integrated into ABAQUS CAE FE software through a user-defined material subroutine (UMAT). The simulated outcomes acquired from diverse material models are validated with relevant experimental findings, and the effectiveness of each material model is evaluated through qualitative and quantitative assessments. Observations reveal limitations in the existing models to accurately replicate material behavior under tension, particularly in the dynamic strain rate, and elevated temperature range. Consequently, a modified version of the JC model (MJC) is explored to better account for the impact of temperature on strain hardening and strain rate hardening. The proposed modification in the material model significantly enhances the predictive accuracy of FE simulations of tensile deformation across the entire spectrum of studied strain rates and temperatures compared to the original JC and RK models.

Deformation and failure behavior of 2024-T42 sheet under impact loading

The deformation and failure behavior of 2024-T42 aluminum alloy sheet was investigated through a combined experimental-numerical method. Nine types of specimens were designed to cover a wide range of stress triaxialities and strain rates. Quasi-static and dynamic tests were carried out by electronic testing machine and split Hopkinson tensile bar respectively, and digital image correlation (DIC) method was introduced to measure the deformation. The phenomenological damage model GISSMO (generalized incremental stress state dependent damage model) and Johnson-Cook model were adopted to simulate all of the above tests and the load-displacement curves through numerical simulation were derived. An optimization method was developed to obtain all the model parameters by matching the load-displacement curves from simulation with those from tests by LS-OPT. Finally, drop weight tests and tensile tests of the central-hole plate were conducted. The applicability and accuracy of the damage models were verified by comparing the simulation results with the experiments, which indicates that GISSMO model predicts better the tests than the Johnson-Cook failure model.

Modeling and simulation of the negative angle cutting with a combined constitutive model for U71Mn rail steel

Due to the increasing train axle load, running speed and traffic volume, rails are prone to severe rolling contact fatigue (RCF) defects. Repairing the rail profile by milling is the latest technology to solve the above hidden problems, but there are few related studies in recent years. In this paper, the milling maintenance process of rails is studied by using finite element method(FEM). This study examines the fracture behavior of U71Mn steel rail under various stress triaxiality conditions, temperatures, and strain rates. An electronic universal testing machine is utilized to conduct the experiments, and a Johnson-Cook (J-C) failure model for U71Mn steel rail is developed. A 3D cutting simulation model was developed using the Johnson-Cook (J-C) combined constitutive model. The accuracy and reliability of the numerical simulation model were confirmed by comparing the cutting force and chip morphology obtained from both simulation and experimental results. The cutting simulation model had an error rate of within 10 % when predicting the cutting force. Following that, the fracture zone and chip portion of the tensile specimen were metallographically analyzed. The applicability of the ductile failure criterion in describing the observed failure in the U71Mn rail has been proven.

Study on the Fracture Behaviour of 6061 Aluminum Alloy Extruded Tube during Different Stress Conditions

To study the deformation and fracture mechanism of 6061 aluminum alloy extruded pipe after secondary heat treatment under different stress triaxiality, a Johnson–Cook failure model was developed. Through the FEM method and SEM, the fracture mechanism of different types of aluminum alloy tensile specimens was analyzed. The research results show that the Johnson–Cook failure model could better simulate the tensile deformation of 6061 aluminum alloy specimens of different types, the parameters of the Johnson–Cook failure model were finally obtained D1 = 0.29, D2 = 1.356, and D3 = −2.567. With the increase of the stress triaxiality, the fracture strain showed a decreasing trend as a whole, and the fracture mechanism changed from a shear type to a hole aggregation type. The stress triaxiality gradually decreased with the increase of the notch radius/angles of the aluminum alloy notch specimen, and the stress triaxiality at the center of the notch was higher than the stress triaxiality at the root of the notch.

Mechanical Properties and Fracture Behavior of a TC4 Titanium Alloy Sheet

TC4 titanium alloy has excellent comprehensive properties. Due to its light weight, high specific strength, and good corrosion resistance, it is widely used in aerospace, military defense, and other fields. Given that titanium alloy components are often fractured by impact loads during service, studying the fracture behavior and damage mechanism of TC4 titanium alloy is of great significance. In this study, the Johnson-Cook failure model parameters of TC4 titanium alloy were obtained via tensile tests at room temperature. The mechanical behavior of TC4 titanium alloy during the tensile process was determined by simulating the sheet tensile process with the finite element software ABAQUS. The macroscopic and microscopic morphologies of tensile fracture were analyzed to study the deformation mechanism of the TC4 titanium alloy sheet. The results provide a theoretical basis for predicting the fracture behavior of TC4 titanium alloy under tensile stress.

On the Role of Damage Evolution in Finite Element Modeling of the Cutting Process and Sensing Residual Stresses.

This study focuses on the role of the damage evolution when estimating the failure behavior of AISI 1045 steel for sensing and measuring metal cutting parameters. A total of five Lagrangian explicit models are established to investigate the effect of applying damage evolution techniques. The Johnson-Cook failure model is introduced once to fully represent damage behavior, i.e., no damage evolution is considered, and as a damage initiation criterion in the remaining approaches. A fracture energy-based model is included to model damage propagation with different evolution rates. Temperature-dependent and temperature-independent fracture energy models are also investigated. Dry orthogonal cutting and residual stresses measurements of AISI 1045 are conducted for validation. The significance of the damage evolution is investigated using honed-tool and sharp-tool models. Including the damage evolution led to a prediction of higher workpiece temperatures, plastic strains, cutting forces, and residual stresses, with no clear differences between linear and exponential evolution rates. The role of damage evolution is more evident when temperature-dependent evolution models are used.

Simulation of Particle Interaction with Surface Microdefects during Cold Gas-Dynamic Spraying

The cold gas-dynamic spray (CGDS) technique is utilized for repairing processes of a large number of metallic components in mechanical and process engineering, such as bridges or vehicles. Fine particles impacting on the component surface can be severely deformed and penetrate into the defects, filling and coating them, resulting in possible protection against corrosion or crack propagation. This work focuses on the investigation of the impact behavior of cold sprayed particles with the wall surface having microdefects in the form of cavities. The collision of fine single particles with the substrate, both made from AISI 1045 steel, was simulated with the finite element method (FEM) using the Johnson–Cook failure model. The impact phenomena of particles on different microdefect geometries were obtained and compared with the collision on a smooth surface. The particle diameter and defect were varied to investigate the influence of the size on the deformation behaviour. The different impact scenarios result in different temperature and stress distributions in the contact zone, penetration and deformation behavior during the collision.

Temperature Analysis of Friction Stir Welding (AA6061-T6) with Coupled Eulerian-Lagrangian Approach.

For Friction Stir Welding (FSW), several simplified FEM models have been developed to explain key parts of thermal-mechanical phenomena. In this study, to simulate the FSW process of the AA6061-T6 aluminum alloy, a thermo-mechanical 3-D finite element model based on the Coupled Eulerian-Lagrangian (CEL) approach is used. The CEL method combines the benefits of both the Lagrangian and Eulerian approaches, allowing it to solve large-scale deformation issues. The Abaqus/CAE software is used to simulate the stages of the FSW process using the Johnson–Cook material law and the Johnson-Cook failure model. The CEL approach is used to estimate process parameters based on the model's boundary conditions of the 3-D rigid tool. Thermocouples were installed in the appropriate positions on the AA6061-T6 plate, and temperature is correlated with the simulation results. The temperature generated during the plunging, dwelling, and welding stages of the FSW of AA6061-T6 is 80% to 90% of the melting temperature being evaluated. The experimental data was obtained from the HMT made CNC (Siemens) operated VMC and the same is compared with the results obtained from the overall FEM simulation.

Numerical simulation of ballistic impact on aluminium 5083-H116 plate with Johnson cook plasticity model

Nowadays, a numerical simulation study using finite element method is very famous among the engineers and scientists, because it not only reduces the cost of the entire project but also saves a lot more time. The results of the numerical simulations needed to validate through experiments. So, we can say that numerical simulation studies reduce the no. Of experiments taken, if it cannot eliminate. In this research, a ballistic impact on the aluminium AA5083-H116 plate by using a rigid steel projectile is examined through numerical simulations in LS-Dyna Solver by using Johnson-Cook (J-C) failure model, which uses a 3-Dimensional nonlinear dynamic finite element code which is explicit in nature. The J-C plasticity model is used for simulation because it can capture large strain, strain rate hardening, and fracture encountered at high-velocity ballistic impacts. The aluminium plate is impacted by a rigid projectile with six different velocities. In the deformed plate, the variation of pressure on the plate at different points during impact, residual projectile velocity and the variation of axial and shear stresses are evaluated and studied. The results obtained from this research may be used to understand the failure behaviour of aluminium alloys, which can be used in the design and fabrication of lightweight bulletproof vehicle outer surface, thin armour portable shelters, and in other engineering applications.

Determination of Johnson–Cook Material Parameters for Armour Plate Using DIC and FEM

Understanding of material behavior of armour steel under large deformations and high strains during loading is very crucial in designing steel structures for various applications. Johnson–Cook flow stress and Johnson–Cook failure models were adopted for modeling and predicting the material flow behavior of armour plate. The material parameters of Johnson–Cook flow stress have been determined experimentally from tests performed at different strain rates (10−4–1550 s−1) and temperatures (25–600 °C). The damage parameters of Johnson–Cook failure model were determined through experiments on flat tensile specimens in combination with finite element simulation. Using these materials parameters, finite element simulations were performed on notch specimens of different radii between 2 mm and 20 mm loaded under tension. Load-strain curves were in good agreement with the experimentally obtained data. Triaxiality obtained from simulation were matched against the reported values from the literature.

Experimental and numerical investigations into the deformation and fracture behavior of intermetallics and base materials in as-cast Al-Cu compounds

This paper focuses on the mechanical characteristics of as-cast compounds consisting of brass/aluminum. It represents a novel simulation-aided experimental approach for the evaluation of the mechanical behavior of hybrid metallic and non-metallic structures. The bilayer components were fabricated through static compound casting and semi-continuous compound casting. The interface of the as-cast products exhibited intermetallic layers, as well as an anomalous eutectic area in between the base materials. Experimental push-out testing was performed in order to analyze the bonding strength and fracturing of monolithic and hybrid structures. The monolithic sample failure was simulated using the Johnson-Cook failure model. The respective Johnson-Cook parameters C1, C2, and C3 were determined as 0.001, 3.000, and 2.000 for CuZn37, 0.100, 2.000, and 9.000 for AA5083, 0.100, 1.000, and 2.000 for AA6060, as well as 0.100, 0.100, and 10.000 for AA7075. A hybrid push-out simulation model was calibrated in order to evaluate the mechanical behavior of hybrid specimens. Two different fracture models, the Johnson-Cook damage criterion and the brittle cracking model, were chosen for the intermetallic layers and anomalous eutectic region. The Johnson-Cook parameters were 0.05, 0.05, and 0.05 for the intermetallic layers, as well as 0.20, 0.20, and 0.20 for the anomalous eutectic area. The tensile strength of the brittle cracking model was 190 N mm-2 for both components. The calibrated and validated material properties were adapted to the simulation-aided investigation into the mechanical behavior during Brazilian testing. Testing of bilayer samples with disparate interfacial bonding underlined the importance of metallurgical bonding in as-cast brass/aluminum compounds.

Design, FEM Analysis and Compression Tests on Energy-Absorbing Property of Disordered Cellular Solids Developed by 3D-Voronoi Division

Lightweight cellular solids have been used as an energy-absorbing material for automotive and aerospace applications. Additive manufacturing is a useful process for the design and manufacture of cellular solids. The present study focuses on the relationship between the energy-absorbing property and the cell structure of additively manufactured porous aluminum alloys. Disordered cell structures with different regularity are designed by the technique of 3D-Voronoi division. Open-cell structures with a porosity of 90% and a strut diameter of 1 mm are generated using commercial 3D CAD software. Explicit FEM analysis including a Johnson-Cook failure model successfully simulates the compressive stress-strain curves of disordered porous aluminum alloys. Experimental results of compression tests were in good qualitative agreement with the FEM analysis. The ordered cell structure with high regularity is disadvantageous for energy-absorbing applications because of the formation of a macroscopic shear band. A slightly low cell regularity in a additively manufactured cellular solid is effective for increasing energy absorption.

Tensile behavior and failure model of Ti–6Al–4V under different orientation and strain rate

In this paper, the objective was to investigate the coupling effect of different orientation and strain rate on the failure behavior of Ti–6Al–4V. The measurement was completed with the quasi static and dynamic tensile test under different orientation of 0°–90° and strain rate ranging from 0.0001–3500 s−1. The strain rate term of the Johnson-Cook(J-C) failure model that considered the coupling effect of different orientation and strain rate was modified. The simulation was accomplished with the modified J-C failure model. The results indicated that the model provided a practicable method to describe the failure behavior under different orientation and strain rate. Finally, the failure form of specimen tested under different orientation and strain rate was analyzed in detail by the scanning electron microscopy (SEM).

Brinell indentation behavior of the stainless steel X2CrNi18-9: Modeling and experiments

Stainless steel X2CrNi18-9 plays an important role in many industrial fields, namely in the agro alimentary industry based on its corrosion resistance. Meanwhile, its mechanical and tribological resistance still presents a challenge. In the olive oil extraction industry, the stainless steel X2CrNi18-9 presents a complex damage mechanism under concentrated load. In the present study, a Brinell indentation test was carried out on the stainless steel X2CrNi18-9 under a load range between F = 10 N and F = 613 N. A three-dimensional finite element (FE) model has been elaborated in order to simulate and understand the mechanical response under this specific concentrated load given by the Brinell test. The mechanical behavior of stainless steel has been described by the Johnson-Cook elasto-plastic model and its damage mode by the Johnson-Cook failure model. The main experimental and numerical results show a stress concentration in the border and in the center of the indents throughout the indentation tests caused by the plastic deformation. The SEM investigations show typical indents increasing in size with increasing load and a pile-up phenomenon as a result of a large E/Y ratio (Young's modulus/yield stress). The elaborated FE numerical model of the Brinell indentation test shows a very satisfactory correlation to the experimental test results.

Flow behavior of diffusion bonding interface of Ti6Al4V alloy over a wide range of strain rates

Quasi-static and dynamic tensile tests were conducted to measure diffusion bonding (DB) interface strength of Ti6Al4V alloy at different strain rates. The effect of strain rate on fracture mode was analyzed by the fractography analyses. A modified Johnson-Cook (JC) model was proposed to describe the stress-strain behavior of DB interface, where the strain rate hardening coefficient had a nonlinear relationship with the strain and the strain rate. The JC failure model with calibrated material constants was used to predict the failure strain of DB interface. Using Abaqus/Explicit through a VUHARD subroutine, the modified JC model and the JC failure model were verified by predicting load-elongation curves and failure strains at three strain rates. The models are capable of describing the mechanical behavior of DB interface for Ti6Al4V alloy.

Effect of radial clearance and holes as crush initiators on the crashworthiness performance of bi-tubular profiles

The use of bi-tubular structures has gained importance in the design of energy absorption systems for protection of passengers in train collisions. Therefore, it is critical to improve the crashworthiness performance of bi-tubular profiles. For this purpose, the effect of cross-section, bi-tubular clearance and holes as crush initiators is evaluated using finite element simulations. To get reliable outcomes, special emphasis was set on the progressive damage modelling of aluminum 6063-T5 by a Johnson-Cook (J-C) failure model. During the cross-section study, bi-tubular arrangements based on polygonal and circular cross-section were evaluated by quasi-static compression loads. The results indicate that the circular shapes showed better crashworthiness performance or crush force efficiency (CFE) up to 12.28% respect to a square base structure. A 10.72% improvement in CFE was obtained when the non-dimensionalized clearance between profiles is increased from λ=20 to λ=40. The effect of holes on crashworthiness performance was evaluated by drilling holes at different locations both in the inner and outer profiles. The results show that the use of holes increased the crush force efficiency and energy absorption (Ea) capability even more than the effect of clearance alone. Improvements in the order of 2.50% and 12.96% for Ea and CFE respectively were computed when holes were placed at the top end of a BC-3 profile with a non-dimensional clearance of λ=40. Considering all effects simultaneously, an increase of 24.6% and 26.31% for Ea and CFE respectively was calculated. Finally, an application to a crash buffer in a railway transport system is considered. Likewise, its improved crashworthiness behavior is presented.

Numerical analysis of energy absorption behaviour of circular profiles with plates under lateral loads

The study of bending behaviour of thin-walled structures has gained importance since lateral impact is the second most common scenario in automobile crashes. The current paper analyses an effect of partition plates on energy absorption (Ea) of circular profiles under lateral loads. For this purpose, several numerical analyses using Abaqus/Explicit finite element software were carried out. The evaluated specimens have circular cross-sections reinforced by different arrangement of partition plates. In order to get reliable outcome, special emphasis was placed on damage modelling by Johnson-Cook failure model for aluminium. From the results considering a single profile, better Ea was registered for structures with plates in a range from 6% to 34%. Reduction in peak load (Pmax) up to 13% and an increase in crush force efficiency (CFE) in 14.86% was also computed. Regarding profiles with plates, it was determined that crashworthiness performance depends on an arrangement of plates on the cross-section more than their thickness and number. Better performance was obtained when the circular cross-section was reinforced in the longitudinal and transversal direction by 4 plates.

Modeling of friction-stir butt-welds and its application in automotive bumper impact performance Part 1. Thermo-mechanical weld process modeling

The demand for better structural performance in joining of components for road vehicles prompts the implementation of aluminum alloy friction stir welding technology in the automotive industry. The aim of current study is the creation of a 3-D finite element (FE) friction thermal model and stir welding (FSW) process of dissimilar aluminum alloy and for the estimation of crash worthiness performance of FSW fabricated shock absorber assembly. Thermo mechanical simulations and analysis are performed to understand the thermal behavior in the FSW weld zones. The developed models are correlated against published experimental results in terms of temperature profile of the weld zone. The developed models are then implemented for fabricating vehicle bumper parts to illustrate the performance of FSW welded components during an impact. Customary sled testing for low-speed guard necessities is performed utilizing a grating blend welded test apparatus at Wichita State University (WSU) at the National Institute for Aviation Research (NIAR). A few guard congregations are then appended to the test installation utilizing FSW and conventional Gas bend GMAW welding strategies. Numerical models are likewise created where limited component investigation is utilized to contrast the anticipated harm and the real harm maintained by both of the FSW and GMAW manufactured guards. During the research, a new FSW weld mold is created that allows for a better representation of the desired progressive crack propagation. The FSW fabricated bumper based on the Johnson-Cook failure model yields better failure prediction and is in good agreement to the test. The results from this study provide a guideline for an accurate finite element modeling of a FSW fabricated components and their application in the crashworthiness of such structural components.