Electromagnetic Forming and Perforation of Tubes: Modeling, Simulation, and Validation

2020 ◽  
Vol 143 (6) ◽  
Author(s):  
Sagar Pawar ◽  
Dinesh Ray ◽  
Sachin D. Kore ◽  
Arup Nandy
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Electromagnetic Forming ◽  
Material Behavior ◽  
Experimental Results ◽  
Discharge Energy ◽  
Coupled Simulation ◽  
Element Analysis ◽  
Failure Patterns

Abstract Electromagnetic forming and perforation (EMFP) is an innovative practice where magnetic forces are used for simultaneous forming and perforation operation. This method is complex, which involves a high strain rate as well as high transformation velocities. It is carried out in a short duration of time, and it includes multiple operations, which increases the complexity in understanding the shearing and forming behavior of the material. To understand this behavior, coupled and non-coupled simulation models have been developed and compared with experimental results. Material and failure models are used for simulating the material behavior at a high strain rate. At lower discharge energy, the coupled model failed to capture the initiation of perforation, but numerical results are found 96% in agreement with experimental results. While on the other hand, on the same discharge energy, non-coupled simulation shows 94% agreement and it succeeded in capturing the initiation of perforation. The von-Mises stresses found in all cases are more than 4e+08 Pa which is found higher than the ultimate strength of the material which is resulting in shearing. The failure patterns obtained in finite element analysis (FEA) simulation for both pointed and concave punch perforation show good agreement with general finding in experiments which shows the prediction capability of developed models.

The Effect of Strain Rate on the Material Characteristics of Nickel-Based Superalloy Inconel 718

2007 ◽  
Vol 340-341 ◽  
pp. 283-288 ◽  
Author(s):  
Jung Han Song ◽  
Hoon Huh
Keyword(s):  
Dynamic Response ◽  
High Strain Rate ◽  
Strain Rate ◽  
Turbine Blade ◽  
Inconel 718 ◽  
High Speed ◽  
High Strain ◽  
Split Hopkinson Pressure Bar ◽  
Experimental Results ◽  
Stress Wave Propagation

The dynamic response of the turbine blade materials is indispensable for analysis of erosions of turbine blades as a result of impulsive loading associated with gas flow. This paper is concerned with the dynamic material properties of the Inconel 718 alloy which is widely used in the high speed turbine blade. The dynamic response at the corresponding level of the strain rate should be acquired with an adequate experimental technique and apparatus due to the inertia effect and the stress wave propagation. In this paper, the dynamic response of the Inconel 718 at the intermediate strain rate ranged from 1/s to 400/s is obtained from the high speed tensile test and that at the high strain rate above 1000/s is obtained from the split Hopkinson pressure bar test. The effects of the strain rate on the dynamic flow stress, the strain rate sensitivity and the failure elongation are evaluated with the experimental results. Experimental results from both the quasi-static and the high strain rate up to 3000/s are interpolated in order to construct the constitutive relation that should be applied to simulate the dynamic behavior of the turbine blade made of the Inconel 718.

Experimental and Numerical Study of Soft Tissue Surrogate Behavior Under Ballistic Loading

2012 ◽  
Author(s):  
Ericka K. Amborn ◽  
Karim H. Muci-Küchler ◽  
Brandon J. Hinz
Keyword(s):  
Soft Tissue ◽  
Constitutive Model ◽  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Split Hopkinson Pressure Bar ◽  
Numerical Study ◽  
Constitutive Models ◽  
Material Behavior ◽  
Good Representation

Studying the high strain rate behavior of soft tissues and soft tissue surrogates is of interest to improve the understanding of injury mechanisms during blast and impact events. Tests such as the split Hopkinson pressure bar have been successfully used to characterize material behavior at high strain rates under simple loading conditions. However, experiments involving more complex stress states are needed for the validation of constitutive models and numerical simulation techniques for fast transient events. In particular, for the case of ballistic injuries, controlled tests that can better reflect the effects induced by a penetrating projectile are of interest. This paper presents an experiment that tries to achieve that goal. The experimental setup involves a cylindrical test sample made of a translucent soft tissue surrogate that has a small pre-made cylindrical channel along its axis. A small caliber projectile is fired through the pre-made channel at representative speeds using an air rifle. High speed video is used in conjunction with specialized software to generate data for model validation. A Lagrangian Finite Element Method (FEM) model was prepared in ABAQUS/Explicit to simulate the experiments. Different hyperelastic constitutive models were explored to represent the behavior of the soft tissue surrogate and the required material properties were obtained from high strain rate test data reported in the open literature. The simulation results corresponding to each constitutive model considered were qualitatively compared against the experimental data for a single projectile speed. The constitutive model that provided the closest match was then used to perform an additional simulation at a different projectile velocity and quantitative comparisons between numerical and experimental results were made. The comparisons showed that the Marlow hyperelastic model available in ABAQUS/Explicit was able to produce a good representation of the soft tissue surrogate behavior observed experimentally at the two projectile speeds considered.

scholarly journals Compressive Mechanical Properties of Porcine Brain: Experimentation and Modeling of the Tissue Hydration Effects

2019 ◽  
Vol 6 (2) ◽  
pp. 40 ◽  
Author(s):  
Raj K. Prabhu ◽  
Mark T. Begonia ◽  
Wilburn R. Whittington ◽  
Michael A. Murphy ◽  
Yuxiong Mao ◽  
...  
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
Water Content ◽  
Mechanical Response ◽  
High Strain ◽  
Peak Stress ◽  
Human Head ◽  
Element Analysis ◽  
Porcine Brain ◽  
Strain Behavior

Designing protective systems for the human head—and, hence, the brain—requires understanding the brain’s microstructural response to mechanical insults. We present the behavior of wet and dry porcine brain undergoing quasi-static and high strain rate mechanical deformations to unravel the effect of hydration on the brain’s biomechanics. Here, native ‘wet’ brain samples contained ~80% (mass/mass) water content and ‘dry’ brain samples contained ~0% (mass/mass) water content. First, the wet brain incurred a large initial peak stress that was not exhibited by the dry brain. Second, stress levels for the dry brain were greater than the wet brain. Third, the dry brain stress–strain behavior was characteristic of ductile materials with a yield point and work hardening; however, the wet brain showed a typical concave inflection that is often manifested by polymers. Finally, finite element analysis (FEA) of the brain’s high strain rate response for samples with various proportions of water and dry brain showed that water played a major role in the initial hardening trend. Therefore, hydration level plays a key role in brain tissue micromechanics, and the incorporation of this hydration effect on the brain’s mechanical response in simulated injury scenarios or virtual human-centric protective headgear design is essential.

Influence of Temperature and Heat-Aged Condition on the Deformation Behavior of Rubber Material Using SHPB Technique with a Pulse Shaper

2007 ◽  
Vol 353-358 ◽  
pp. 619-626
Author(s):  
Ouk Sub Lee ◽  
Yong Hwan Han ◽  
Dong Hyeok Kim
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
Deformation Behavior ◽  
High Strain ◽  
Dynamic Deformation ◽  
Material Behavior ◽  
Pulse Shaper ◽  
Rubber Material ◽  
Experimental Apparatus ◽  
Pressure Bar

The Split Hopkinson Pressure Bar (SHPB) technique with some special experimental apparatus can be used to obtain the dynamic material behavior under high strain rate loading conditions. An experimental technique that modifies the conventional SHPB has been developed for measuring the compressive stress strain responses of materials with low mechanical impedance and low compressive strengths such as rubber. This paper uses PEEK (Poly-ether-ether-ketone plastic) bars to achieve a closer impedance match between the pressure bar and the specimen materials. In addition, a pulse shaper is utilized to lengthen the rise time of the incident pulse to ensure stress equilibrium and homogeneous deformation of the rubber specimen. It is confirmed that the modified technique is useful to record the dynamic deformation behavior of rubbers under various conditions such as high strain rate with various temperature effect. Furthermore, the dynamic deformation behaviors of heat-aged rubber material under compressive high strain rate are evaluated using the modified SHPB technique.

scholarly journals Mechanical Response of Porcine Liver Tissue under High Strain Rate Compression

2019 ◽  
Vol 6 (2) ◽  
pp. 49 ◽  
Author(s):  
Joseph Chen ◽  
Sourav S. Patnaik ◽  
R. K. Prabhu ◽  
Lauren B. Priddy ◽  
Jean-Luc Bouvard ◽  
...  
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
Liver Tissue ◽  
High Strain ◽  
Material Behavior ◽  
Stress Profile ◽  
Strain Rates ◽  
High Strain Rates ◽  
Porcine Liver ◽  
Strain Rate Compression

In automobile accidents, abdominal injuries are often life-threatening yet not apparent at the time of initial injury. The liver is the most commonly injured abdominal organ from this type of trauma. In contrast to current safety tests involving crash dummies, a more detailed, efficient approach to predict the risk of human injuries is computational modelling and simulations. Further, the development of accurate computational human models requires knowledge of the mechanical properties of tissues in various stress states, especially in high-impact scenarios. In this study, a polymeric split-Hopkinson pressure bar (PSHPB) was utilized to apply various high strain rates to porcine liver tissue to investigate its material behavior during high strain rate compression. Liver tissues were subjected to high strain rate impacts at 350, 550, 1000, and 1550 s−1. Tissue directional dependency was also explored by PSHPB testing along three orthogonal directions of liver at a strain rate of 350 s−1. Histology of samples from each of the three directions was performed to examine the structural properties of porcine liver. Porcine liver tissue showed an inelastic and strain rate-sensitive response at high strain rates. The liver tissue was found lacking directional dependency, which could be explained by the isotropic microstructure observed after staining and imaging. Furthermore, finite element analysis (FEA) of the PSHPB tests revealed the stress profile inside liver tissue and served as a validation of PSHPB methodology. The present findings can assist in the development of more accurate computational models of liver tissue at high-rate impact conditions allowing for understanding of subfailure and failure mechanisms.

High Strain Rate Constitutive Modeling of Pure Titanium Using the Taylor Impact Test

2014 ◽  
Author(s):  
Mark E. Barkey ◽  
Haleigh Ball ◽  
Stanley E. Jones ◽  
Pingsha Dong
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
Compressive Stress ◽  
High Strain ◽  
Rolling Direction ◽  
Pure Titanium ◽  
Element Analysis ◽  
One Dimensional ◽  
Specimen Diameter ◽  
Taylor Impact

High strain rate mechanical properties of this material are required for the structural design of ship components for advanced naval applications. Taylor cylinder specimens were machined from pure titanium plate stock proposed for use in ship building. Since the specimens were machined from plate stock, it was assumed that the processing of the plate induced anisotropic behavior. To assure that all the effects would be captured by the tests, specimens were machined in the rolling direction, transverse direction, and 45° to the rolling direction in the plane of the plate. Indeed, distinct differences were observed in the rolling and transverse directions. Specimens in the 45° direction also showed the unsymmetrical deformation field that is associated with anisotropy. There was modest anisotropy in the thickness direction. However, the analysis of the data from the tests required corrections to accommodate this effect. Data from these tests can be reduced using two distinct methods; a one-dimensional theory and a finite element analysis with a conventional constitutive model adjusting the free parameters until the specimen geometry is matched. While the second method usually produces excellent results, we will employ a one-dimensional analysis that was proposed several years ago by one of the authors in this paper. In order to effectively apply such a theory, very low scale specimens, in this case 0.164-inch diameter, are required. The use of such low diameter specimens demands accurate measurement of the specimen profile. The recovered specimens were measured with a laser micrometer and the results were used to find estimates of quasi-static compressive stress and compressive stress at strain rates exceeding 104/sec. Some scatter in the data from these tests was observed. This was mostly due to some variations in the initial specimen diameter. Pure titanium presents a machining challenge for conventional equipment, when a tolerance of a thousandth of an inch is required. The scatter in Taylor cylinder data can be mitigated by conducting a large number of tests. However, in this case, many of the specimens that did not meet the criteria for success were discarded. Nevertheless, the results are very convincing.

scholarly journals Static and Impact-Dynamic Characterization of Multiphase TRIP Steels

2010 ◽  
Vol 638-642 ◽  
pp. 3585-3590 ◽  
Author(s):  
Joost Van Slycken ◽  
Jérémie Bouquerel ◽  
Patricia Verleysen ◽  
Kim Verbeken ◽  
Joris Degrieck ◽  
...  
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Material Behavior ◽  
Experimental Program ◽  
Dynamic Conditions ◽  
Split Hopkinson Tensile Bar ◽  
Rate Dependent ◽  
Study Results ◽  
Steel Grades

In this study, results are presented of an extensive experimental program to investigate the strain rate dependent mechanical properties of various Transformation Induced Plasticity (TRIP) steel grades. A split Hopkinson tensile bar setup was used for the high strain rate experiments and microstructural observation techniques such as LOM, SEM and EBSD revealed the mechanisms governing the observed behavior. With elevated testing temperatures and interrupted tensile experiments the material behavior and the austenite to martensite transformation is investigated. In dynamic conditions, the strain rate has limited influence on the material properties. Yet an important increase is noticed when comparing static to dynamic conditions. The differences in strength, elongation and energy absorption levels observed between the investigated materials can be attributed to their chemical composition. Adiabatic heating during high strain rate deformation tends to slow down the strain induced martensitic deformation. The elongation of the ferritic and austenite constituents is found to be strain rate dependent and the strain induced martensitic transformation occurs gradually in the material.

Random Aggregate Generation and Mesoscale Modeling of Concrete under High Strain Rate Compression

2011 ◽  
Vol 71-78 ◽  
pp. 733-736 ◽  
Author(s):  
Xiao Qing Zhou ◽  
Yong Xia
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
Coarse Aggregate ◽  
High Strain ◽  
Concrete Specimen ◽  
Material Behavior ◽  
Mesoscale Modeling ◽  
Aggregate Distribution ◽  
Random Aggregate ◽  
Strain Rate Compression

In the mesoscale modeling, concrete is assumed consisting of three components, i.e., coarse aggregates, mortar matrix, and the interfacial transition zone (ITZ), each with different material behavior. The shape and the percentage of the coarse aggregate are the key factors in the mesoscale numerical simulation. The present paper investigates the effect of the coarse aggregate shape on the concrete behavior under high strain rate compression. Simplified methods are adopted to construct the aggregate distribution. Three different aggregate shapes, i.e., circular, oval and polygons, are generated to model the gravel and crushed stone aggregates, respectively. Using these different aggregate shapes, concrete specimens under high strain rate compression are modeled. Numerical results show that the aggregate shapes have a significant effect on the crack path, whereas little effect on the overall responses of the concrete specimen.

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