Experimental Calibration of ISV Damage Model Constants for Pure Copper for High-Speed Impact Simulation

2016 ◽  
Author(s):  
Yangqing Dou ◽  
Yucheng Liu ◽  
Wilburn Whittington ◽  
Jonathan Miller
Keyword(s):  
High Speed ◽  
Impact Analysis ◽  
Split Hopkinson Pressure Bar ◽  
Internal State ◽  
Pure Copper ◽  
Damage Model ◽  
Hopkinson Pressure Bar ◽  
Experimental Calibration ◽  
High Speed Impact ◽  
The Impact

Coefficients and constants of a microstructure-based internal state variable (ISV) plasticity damage model for pure copper have been calibrated and used for damage modeling and simulation. Experimental stress-strain curves obtained from Cu samples at different strain rate and temperature levels provide a benchmark for the calibration work. Instron quasi-static tester and split-Hopkinson pressure bar are used to obtain low-to-high strain rates. Calibration process and techniques are described in this paper. The calibrated material model is used for high-speed impact analysis to predict the impact properties of Cu. In the numerical impact scenario, a 100 mm by 100 mm Cu plate with a thickness of 10 mm will be penetrated by a 50 mm-long Ni rod with a diameter of 10mm. The thickness of 10 mm was selected for the Cu plate so that the Ni-Cu penetration through the thickness can be well observed through the simulations and the effects of the ductility of Cu on its plasticity deformation during the penetration can be displayed. Also, that thickness had been used by some researchers when investigating penetration mechanics of other materials. Therefore the penetration resistance of Cu can be compared to that of other metallic materials based on the simulation results obtained from this study. Through this study, the efficiency of this ISV model in simulating high-speed impact process is verified. Functions and roles of each of material constant in that model are also demonstrated.

scholarly journals Experimental and Numerical Impact Analysis of Automotive Bumper Brackets Made of 2D Triaxially Braided CFRP Composites

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3554
Author(s):  
Robert Böhm ◽  
Andreas Hornig ◽  
Tony Weber ◽  
Bernd Grüber ◽  
Maik Gude
Keyword(s):  
High Speed ◽  
Impact Analysis ◽  
Damage Model ◽  
Drop Tower ◽  
Structural Deformation ◽  
Impact Behavior ◽  
Speed Test ◽  
Damage Models ◽  
The Impact ◽  
Carbon Fiber Epoxy

The impact behavior of carbon fiber epoxy bumper brackets reinforced with 2D biaxial and 2D triaxial braids was experimentally and numerically analyzed. For this purpose, a phenomenological damage model was modified and implemented as a user material in ABAQUS. It was hypothesized that all input parameters could be determined from a suitable high-speed test program. Therefore, novel impact test device was designed, developed and integrated into a drop tower. Drop tower tests with different impactor masses and impact velocities at different bumper bracket configurations were conducted to compare the numerically predicted deformation and damage behavior with experimental evidence. Good correlations between simulations and tests were found, both for the global structural deformation, including fracture, and local damage entities in the impact zone. It was proven that the developed phenomenological damage models can be fully applied for present-day industrial problems.

An improved method for compressive stress-strain measurements at very high strain rates

1992 ◽  
Vol 438 (1902) ◽  
pp. 153-170 ◽  
Keyword(s):  
High Speed ◽  
Split Hopkinson Pressure Bar ◽  
Pure Copper ◽  
High Strength ◽  
Tungsten Alloy ◽  
High Speed Photography ◽  
Hopkinson Pressure Bar ◽  
Stress Strain ◽  
Split Hopkinson ◽  
Pressure Bar

This paper describes a modification of the split Hopkinson pressure bar, to allow compression testing of high strength metals at a strain rate of up to about 10 5 s –1 . All dimensions are minimized to reduce effects of dispersion and inertia, with specimens of the order of 1 mm diameter. Strain is calculated from the stress record and calibrated with high-speed photography. Particular attention has been paid to the accuracy of the technique, and errors arising from nonlinearity in the instrumentation, dispersion, frictional restraint and inertia have all been quantitatively assessed. Stress–strain results are presented of Ti 6A14V alloy, a high strength tungsten alloy, and pure copper.

Differences of transverse impact damages in 3D angle-interlock woven composites between warp and weft directions

2019 ◽  
Vol 28 (8) ◽  
pp. 1203-1227 ◽  
Author(s):  
Chunlei Ren ◽  
Amna Siddique ◽  
Baozhong Sun ◽  
Bohong Gu
Keyword(s):  
Finite Element ◽  
High Speed ◽  
Split Hopkinson Pressure Bar ◽  
Kink Band ◽  
Woven Composites ◽  
Hopkinson Pressure Bar ◽  
Transverse Impact ◽  
Element Analysis ◽  
The Impact ◽  
Impact Damages

Transverse impact damages of 3D angle-interlock woven composites have been tested at split Hopkinson pressure bar along warp and weft directions respectively. The impact deformation and damages were photographed with a high-speed camera. A finite element analyses model was established at mesostructure level to unveil the inner yarn, resin damages, and stress distributions. There are significant differences of yarn breakages and interface damage between the two directions. From finite element analysis simulations and scanning electron microscope photographs, we found the warp yarns were in kink band deformation and shear damage, while the weft yarns were in compressive failure and had smooth fractography. The warp yarns which run through-thickness directions impede transverse impact crack propagations in resins and lead to high delamination resistances. The straight weft yarns impart high stiffness and strength to in-plane directions.

SHPB Dynamic Experiment on Silica Fume Concrete

2013 ◽  
Vol 631-632 ◽  
pp. 771-775 ◽  
Author(s):  
Rong Jun Chen ◽  
Hong Wei Liu ◽  
Rui Zeng
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Silica Fume ◽  
High Speed ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Compression ◽  
Impact Resistance ◽  
Dynamic Mechanical Properties ◽  
Hopkinson Pressure Bar ◽  
The Impact

Dynamic mechanical properties of silica fume concrete in a number of strain rate under the conditions of dynamic compression mechanical properties subjected to various strain rates were studied, and gained the stress versus strain curves, details of an experimental investigation using 74 mm-diameter split Hopkinson pressure bar(SHPB) apparatus were presented. The results showed that: The admixture of silica fume concrete impact resistance, especially under the impact of the performance of high-speed has a very important influence, with the impact velocity increased, the strain rate increase, and its impact more obvious.

Comparison of Johnson-Cook Model and an ISV Plasticity Damage Model in Penetration Simulation

2016 ◽  
Author(s):  
Yangqing Dou ◽  
Yucheng Liu ◽  
Youssef Hammi
Keyword(s):  
High Speed ◽  
Internal State ◽  
Damage Model ◽  
Rate Equations ◽  
State Variables ◽  
High Speed Impact ◽  
Internal States ◽  
Penetration Mechanics ◽  
History Of ◽  
Cook Model

This paper compares Johnson-Cook model and an internal state variable (ISV) damage model developed by Bammann and Horstemeyer in simulating damage behavior of materials during penetration process. Bammann and Horstemeyer’s ISV damage model employs internal state variables and their rate equations to capture the evolution of internal states of materials during high speed impact and penetration. From the calculated internal states, observable states or global penetration and perforation response of materials can be decided. Compared to the JC model, the ISV damage model closely reflect history of materials’ mechanical behavior during the penetration and perforation process. Moreover, the damage model links the global impact and penetration performance of the materials to their microstructural evolution, such as the nucleation, growth, and coalescence of micro voids and cracks. Therefore, it possesses an enhanced predicative capability for high speed impact, penetration, and perforation problems. To demonstrate the reliability of the presented ISV model, that model is applied for studying penetration mechanics of aluminum and the numerical results are validated by comparing with simulation results yielded from the Johnson-Cook model as well as analytical results calculated from an existing theoretical model.

Structure-property relations of a natural composite: Bamboo guadua angustifolia, under impact and flexural loads

2021 ◽  
pp. 002199832110029
Author(s):  
José J Rua ◽  
Mario F Buchely ◽  
Sergio Neves Monteiro ◽  
Henry A Colorado
Keyword(s):  
Impact Analysis ◽  
Natural Fiber ◽  
Split Hopkinson Pressure Bar ◽  
Fiber Composite ◽  
Flexural Behavior ◽  
Structure Property ◽  
Hopkinson Pressure Bar ◽  
Suitable Alternative ◽  
Structural Applications ◽  
The Impact

In this work a natural fiber composite material, the Guadua Angustifolia Kunth from the family of Bamboo is investigated as a suitable alternative for solutions for impact applications, load-bearing, and other structural applications. Since this type of Bamboo grows faster than wood and requires less water and area to reach maturity and be able to crop, it is a competitive, economically, and environmentally solution when is compared to other construction materials. The Bamboo species of interest is a natural one from Colombia and will be evaluated in flexural behavior and under impact response to understand the material subjected under fast loading. Flexural samples were cut parallel to bamboo axial fibers to obtain the highest impact strength. The flexural tests and scanning electron microscopy characterization were included for microstructure analysis. Additionally, compression at high strain rates was characterized by a split-Hopkinson pressure bar (SHPB). Results show flexural strength of about 70 MPa. The impact analysis showed a tough material with very similar values to Charpy notched and dynamic instrumented impact tests.

Analysis of the Impact of the Frequency Range of the Tensometer Bridge and Projectile Geometry on the Results of Measurements by the Split Hopkinson Pressure Bar Method

2013 ◽  
Vol 20 (4) ◽  
pp. 555-564 ◽  
Author(s):  
Wojciech Moćko
Keyword(s):  
Test Bench ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Deformation ◽  
Spectral Width ◽  
Hopkinson Pressure Bar ◽  
Computing Environment ◽  
Split Hopkinson ◽  
Pressure Bar ◽  
The Impact ◽  
Bench Model

Abstract The paper presents the results of the analysis of the striker shape impact on the shape of the mechanical elastic wave generated in the Hopkinson bar. The influence of the tensometer amplifier bandwidth on the stress-strain characteristics obtained in this method was analyzed too. For the purposes of analyzing under the computing environment ABAQUS / Explicit the test bench model was created, and then the analysis of the process of dynamic deformation of the specimen with specific mechanical parameters was carried out. Based on those tests, it was found that the geometry of the end of the striker has an effect on the form of the loading wave and the spectral width of the signal of that wave. Reduction of the striker end diameter reduces unwanted oscillations, however, adversely affects the time of strain rate stabilization. It was determined for the assumed test bench configuration that a tensometric measurement system with a bandwidth equal to 50 kHz is sufficient

scholarly journals Application and Development of an Environmentally Friendly Blast Hole Plug for Underground Coal Mines

2018 ◽  
Vol 2018 ◽  
pp. 1-12
Author(s):  
Donghui Yang ◽  
Yixin Zhao ◽  
Zhangxuan Ning ◽  
Zhaoheng Lv ◽  
Huafeng Luo
Keyword(s):  
Split Hopkinson Pressure Bar ◽  
Low Cost ◽  
Blast Hole ◽  
Environmentally Friendly ◽  
Test System ◽  
Industrial Test ◽  
Labor Intensity ◽  
Rock Blasting ◽  
Hopkinson Pressure Bar ◽  
The Impact

Drilling and blasting technology is one of the main methods for pressure relief in deep mining. The traditional method for blasting hole blockage with clay stemming has many problems, which include a large volume of transportation, excess loading time, and high labor intensity. An environmentally friendly blast hole plug was designed and developed. This method is cheap, closely blocks the hole, is quickly loaded, and is convenient for transportation. The impact test on the plug was carried out using an improved split Hopkinson pressure bar test system, and the industrial test was carried out in underground tunnel of coal mine. The tests results showed that, compared with clay stemming, the new method proposed in this paper could prolong the action time of the detonation gas, prevent premature detonation gas emissions, reduce the unit consumption of explosives, improve the utilization ratio, reduce the labor intensity of workers, and improve the effect of rock blasting with low cost of rock breaking.

High-speed impacts of slender bodies into non-smooth, complex fluids

2018 ◽  
Vol 861 ◽  
Author(s):  
Ishan Sharma
Keyword(s):  
Penetration Depth ◽  
High Speed ◽  
Complex Fluids ◽  
Laboratory Data ◽  
Impact Speed ◽  
High Speed Impact ◽  
Smooth Complex ◽  
Theoretical Predictions ◽  
Slender Bodies ◽  
The Impact

We present a simple hydrodynamical model for the high-speed impact of slender bodies into frictional geomaterials such as soils and clays. We model these materials as non-smooth, complex fluids. Our model predicts the evolution of the impactor’s speed and the final penetration depth given the initial impact speed, and the material and geometric parameters of the impactor and the impacted material. As an application, we investigate the impact of deep-penetrating anchors into seabeds. Our theoretical predictions are found to match field and laboratory data very well.

scholarly journals Towards Standardising SHPB Testing - A Round Robin Exercise

2018 ◽  
Vol 183 ◽  
pp. 02027
Author(s):  
Reuben Govender ◽  
Muhammad Kariem ◽  
Dong Ruan ◽  
Rafael Santiago ◽  
Dong Wei Shu ◽  
...  
Keyword(s):  
Split Hopkinson Pressure Bar ◽  
Pure Copper ◽  
Round Robin ◽  
Standard Test ◽  
Test Method ◽  
Hopkinson Pressure Bar ◽  
Test Procedures ◽  
Draft Standard ◽  
Shpb Test ◽  
Pressure Bar

The Split Hopkinson Pressure Bar (SHPB) test, while widely utilised for high strain rate tests, has yet to be standardised. As an exploratory step towards developing a standard test method or protocol, a Round Robin test series has been conducted between four institutions: (i) Swinburne University of Technology, Australia (ii) University of São Paulo, Brazil, (iii) University of Cape Town, South African and (iv) Nanyang Technological University, Singapore. Each institution prepared specimens from a metallic material, and provided batches of specimens from their chosen material to the other institutions. The materials utilised in this round of testing were commercially pure copper and aluminium, magnesium alloy and stainless steel (316 grade). The intent of the first exercise is to establish the consistency of SHPB test results on nominally identical specimens at comparable elevated strain rates, conducted by different laboratories following notionally similar test procedures with some freedom in data processing. This paper presents and compares the results of the first batch of tests for copper, identifying variations between results from different laboratories. The variation between different laboratories’ results for copper is suffciently small that there is confidence in the potential to develop a draft standard in future.

Sign in / Sign up

Export Citation Format

Share Document