Study on dynamic mechanical properties and constitutive model description of Inconel718

Author(s):  
Yihang Fan ◽  
Bing Wang ◽  
Zhaopeng Hao

In this study, the effects of strain rate and temperature on the flow stress of Inconel718 were analyzed by Split Hopkinson Pressure Bar (SHPB) experiment and quasi-static compression experiment. The classical JC constitutive model was established by combining the quasi-static compression experiment with the SHPB experiment. According to the effects of different grain sizes and [Formula: see text] phase on dislocation pile-up, the dislocation pile-up theory was introduced to modify the JC constitutive model. The modified constitutive model was compiled in FORTRAN language, and VUMAT user material subroutine was called and secondary development was carried out to establish the polycrystalline simulation model with different grain sizes. The uniaxial tensile and compression simulation process of polycrystal with different grain sizes was performed. Through comparing the simulation results with the experimental data. The correlation coefficient R, between the simulation and experimental values, is 0.97,981, and the average relative error is only 3.72%. The accuracy of the modified constitutive model was verified.

2016 ◽  
Vol 693 ◽  
pp. 621-628 ◽  
Author(s):  
Xi Guo Xue ◽  
Li Jing Xie ◽  
Tao Wang

By conducting the quasi-static compression and split Hopkinson pressure bar testing,the flow strain - stress curves under strain rate range of 0.0001-1000/s and temperature range of normal-400°C of different volume fraction SiC particles reinforced metal matrix composite SiCp/6063Al were obtained. The commonly used Johnson-Cook constitutive model in metal materials was applied in this research. And on the basis of it, the influence of volume fraction to flow stress was utilized to establish the equivalent and homogeneous constitutive model.


2013 ◽  
Vol 816-817 ◽  
pp. 84-89
Author(s):  
Yong Gang Kang ◽  
Yuan Yang ◽  
Jie Huang ◽  
Jing Hang Zhu

7075-T651 aluminum alloy are widely used in aeronautical applications such as wing panels, but there is no corresponding constitutive model for it now. In this paper, the flow behavior of 7050-T651 aluminum alloy was investigated by Split Hopkinson Pressure Bar (SHPB) and quasi-static compression experiment system. The strain hardening parameters were obtained by quasi-static compression experiment data, and the strain rate hardening parameters at various strain rates (1000-3000s-1) and room temperature, and the thermal softening parameter at various temperatures (20-300°C) where strain rate is 3000s-1 were obtained by SHPB experiment data. Then the constitutive equation of 7075-T651 aluminum alloy is obtained based on Johnson-Cook constitutive equation model.


2020 ◽  
Vol 1012 ◽  
pp. 89-93
Author(s):  
Anderson Oliveira da Silva ◽  
Ricardo Pondé Weber ◽  
Sergio Neves Monteiro

This work evaluates the mechanical and dynamic behavior of recycled polycarbonate (rPC) from industrial waste. This study aims to verify whether the recycled process adopted for polycarbonate promotes both mechanical and dynamic properties values under compressive stress, similar to those found for virgin polycarbonate. The mechanical recycling of the rPC was carried out using the thermoforming technique in a thermal press. Two tests were carried out to evaluate the dynamic response of rPC. The quasi-static compression test was performed on a universal machine. The dynamic in a split Hopkinson pressure bar was performed with three different strain rates. The results showed that the mechanical and primary recycling adopted in this work promoted values of yield stress in compression (77 MPa) and dynamic (up to 118 MPa), close to or superior to those reported so far in the literature.


Materials ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 66 ◽  
Author(s):  
Jingyuan Zhou ◽  
Liangliang Ding ◽  
Wenhui Tang ◽  
Xianwen Ran

Metal/fluoropolymer materials are typical reactive materials. Polytetrafluoroethylene (PTFE)/Al/CuO reactive materials were studied in this research. Scanning electron microscopy (SEM), quasi-static compression, the Split Hopkinson pressure bar test, and the drop hammer test were used to study the mechanical properties and induced reaction characteristics of the reactive materials with different Al/CuO thermite contents and different particle sizes. SEM images of the samples demonstrate that the reactive materials were mixed evenly. The compression test results show that, if the particle size of PTFE was too small, the strength of reactive materials after sintering was reduced. After sintering, with the increase in the content of Al/CuO thermite, the strength of the micro-sized PTFE/Al/CuO firstly increased and then decreased. The Johnson–Cook constitutive model can be used to characterize the reactive materials, and the parameters of the Johnson–Cook constitutive model of No. 3 reactive materials (PTFE/Al:Al/CuO = 3:1) were obtained. The reliability of the parameters was verified by numerical simulation. Drop hammer tests show that the addition of Al/CuO aluminothermic materials or the use of nano-sized PTFE/Al reactive materials can significantly improve the sensitivity of the material. The research in this paper can provide a reference for the preparation, transportation, storage, and application of reactive materials.


2010 ◽  
Vol 658 ◽  
pp. 193-196
Author(s):  
Masakazu Tane ◽  
Tae Kawashima ◽  
Keitaro Horikawa ◽  
Hidetoshi Kobayashi ◽  
Hideo Nakajima

Dynamic and quasi-static compression tests were conducted on lotus-type porous iron with porosity of about 50% using the split Hopkinson pressure bar method and universal testing machine, respectively. In the dynamic compression parallel to the pore direction, a plateau stress region appears where deformation proceeds at nearly constant stress, while the plateau stress region does not appear in the quasi-static compression. The plateau stress region is probably caused by the buckling deformation of matrix iron which occurs only in the dynamic compression. In contrast, the compression perpendicular to the orientation direction of pores exhibits no plateau-stress regions in the both dynamic and quasi-static compression.


2018 ◽  
Vol 183 ◽  
pp. 01059
Author(s):  
Philip Church ◽  
Peter Gould ◽  
David Williamson

There is a significant challenge in simulating the behaviour of PBXs under high strain rate impact loading. A Porter-Gould physically based constitutive model has been developed for the DPX2 explosive. A series of quasi-static compression and tensile tests over a range of temperatures were performed together with DMA tests to calibrate the model. In particular tests were performed for different L/D ratios to understand the complex localisation and damage behaviour of the material. High rate tests on the compression Split Hopkinson Pressure Bar (SHPB) for a range of temperatures were then used for validation of the model under idealised stress states. Some model development is still required, particularly at lower temperatures near the glass transition temperature. In addition a series of classical Taylor Tests were used to validate the model under impact loading conditions at room temperature. The DYNA3D simulations gave very good results compared to the experiments for these impact conditions.


2019 ◽  
Vol 2019 ◽  
pp. 1-19 ◽  
Author(s):  
Bashir H. Osman ◽  
Xiao Sun ◽  
Zhenghong Tian ◽  
Hao Lu ◽  
Guilin Jiang

The dynamic mechanical properties of concrete materials are important parameters for evaluating the safety performance of concrete structures under dynamic loads. Fiber cement-based materials have been widely used in the construction projects due to their strength, toughening, and cracking resistance. In this study, we conducted experimental and theoretical studies on dynamic compression and tensile mechanical properties of different proportions of new-type fiber concrete. A Split-Hopkinson pressure bar equipment was used to determine the concrete behavior at different strain rates. The effects of strain rate and fiber content on the strength of the specimen, dynamic increase factor, and ultimate strain were analyzed. Based on the macrodamage factor, the traditional nonlinear viscoelastic constitutive model was simplified and improved. The four-parameter constitutive model was obtained, and the influence of these parameters on the performance of fiber concrete was analyzed. The experimental results were compared with those predicted from the available equations, and results were in accordance. Finally, an analytical equation for predicting the dynamic compression and tensile properties of these new-type fibers was proposed.


Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7298
Author(s):  
Shumeng Pang ◽  
Weijun Tao ◽  
Yingjing Liang ◽  
Shi Huan ◽  
Yijie Liu ◽  
...  

Although highly desirable, the experimental technology of the dynamic mechanical properties of materials under multiaxial impact loading is rarely explored. In this study, a true-biaxial split Hopkinson pressure bar device is developed to achieve the biaxial synchronous impact loading of a specimen. A symmetrical wedge-shaped, dual-wave bar is designed to decompose a single stress wave into two independent and symmetric stress waves that eventually form an orthogonal system and load the specimen synchronously. Furthermore, a combination of ground gaskets and lubricant is employed to eliminate the shear stress wave and separate the coupling of the shear and axial stress waves propagating in bars. Some confirmatory and applied tests are carried out, and the results show not only the feasibility of this modified device but also the dynamic mechanical characteristics of specimens under biaxial impact loading. This novel technique is readily implementable and also has good application potential in material mechanics testing.


Polymers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1561 ◽  
Author(s):  
Kebin Zhang ◽  
Wenbin Li ◽  
Yu Zheng ◽  
Wenjin Yao ◽  
Changfang Zhao

The temperature and strain rate significantly affect the ballistic performance of UHMWPE, but the deformation of UHMWPE under thermo-mechanical coupling has been rarely studied. To investigate the influences of the temperature and the strain rate on the mechanical properties of UHMWPE, a Split Hopkinson Pressure Bar (SHPB) apparatus was used to conduct uniaxial compression experiments on UHMWPE. The stress–strain curves of UHMWPE were obtained at temperatures of 20–100 °C and strain rates of 1300–4300 s−1. Based on the experimental results, the UHMWPE belongs to viscoelastic–plastic material, and a hardening effect occurs once UHMWPE enters the plastic zone. By comparing the stress–strain curves at different temperatures and strain rates, it was found that UHMWPE exhibits strain rate strengthening and temperature softening effects. By modifying the Sherwood–Frost model, a constitutive model was established to describe the dynamic mechanical properties of UHMWPE at different temperatures. The results calculated using the constitutive model were in good agreement with the experimental data. This study provides a reference for the design of UHMWPE as a ballistic-resistant material.


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