scholarly journals Numerical material testing using finite element polycrystalline model based on successive integration method

2018 ◽  
Vol 15 ◽  
pp. 1833-1840 ◽  
Author(s):  
Shin Onoshima ◽  
Tetsuo Oya
Keyword(s):  
Finite Element ◽  
Integration Method ◽  
Material Testing ◽  
Model Based ◽  
Polycrystalline Model

Comparing Two Selection Laws of Active Slip Systems in Finite Element Polycrystalline Model for Numerical Material Testing

2018 ◽  
Vol 920 ◽  
pp. 169-174
Author(s):  
Shin Onoshima ◽  
Tetsuo Oya
Keyword(s):  
Strain Rate ◽  
Crystal Orientation ◽  
Integration Method ◽  
Tensile Tests ◽  
Material Testing ◽  
Alloy Sheet ◽  
Material Models ◽  
Rate Dependent ◽  
Dependent Model ◽  
Polycrystalline Model

To meet the demand for high accuracy in metal forming simulation including difficult problems such as anisotropy, many material models have been developed. Since the recent material models usually possess many parameters and require cumbersome experiments, a reliable numerical material testing would be helpful to reduce the number of experiments. Therefore, we have engaged in development of a numerical material testing based on the finite element polycrystalline model in which the successive integration method is used for modeling slip systems. However, implementation based on the strain-rate dependent model, which is considered as the mainstream of such model, has not been rigorously considered in our research. In this study, two polycrystalline models were compared to establish better microstructural modeling for constructing a scheme of numerical material testing to predict material behavior that is not obtained by experiments. Numerical rolling, uniaxial tensile tests were conducted on aluminum alloy sheet with the strain-rate dependent model and the successive integration method. The crystal orientation calculated by the successive integration method exhibited close agreement with the experimental value of the rolled aluminum alloy sheet. On the other hand, the calculated crystal orientation by the strain-rate dependent model exhibited less close agreement with the experimental value of the same material than the successive integration method. To ascertain the characteristics of each model in terms of slip deformation quantitatively, the other tensile tests were conducted to calculate Lankford values caused by crystal orientation. Lankford values, calculated by the successive integration method, exhibited better agreement with experimental values than the strain-rate dependent model. These comparisons indicate that the successive integration method represented slip deformation more physically valid than the strain-rate dependent model and resulted in better calculation.

scholarly journals Study on a New Forming Method—Thread Rolling by Crystal Plasticity Finite Element Simulation

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 503
Author(s):  
Yuheng Zhang ◽  
Zhiqing Hu ◽  
Liming Guo
Keyword(s):  
Finite Element ◽  
Crystal Plasticity ◽  
Strain Curve ◽  
Forming Process ◽  
Crystal Plasticity Finite Element ◽  
Pole Figures ◽  
Grain Orientations ◽  
Thread Rolling ◽  
Polycrystalline Model ◽  
High Consistency

In order to study a new thread rolling forming process from a microscopic perspective, a polycrystalline model was established, based on the crystal plasticity finite element method (CPFEM) and Voronoi polyhedron theory. The fluidity of metals was studied to explain the reason for the concave center. The simulation results show that the strain curve of the representative element can more truly reflect the deformation behavior of the material. The grain orientations after deformation are distributed near the initial orientation. The evolution of each slip system is determined by the initial grain orientations and grain locations. The pole figures obtained from the experiment show high consistency with the pole figures obtained by simulation, which verifies the accuracy of the texture prediction by CPFEM. The experimental results show that thread rolling is more uniform in deformation than ordinary rolling.

An Analysis of Conventional and Self-Aligned four Terminal Resistor Structures for The Determination of The Contact Resistivity from End Resistance Measurements

1986 ◽  
Vol 71 ◽  
Author(s):  
I. Suni ◽  
M. Finetti ◽  
K. Grahn
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Computer Model ◽  
Contact Resistivity ◽  
Experimental Results ◽  
The Finite Element Method ◽  
Model Based ◽  
A Value ◽  
And Diffusion

AbstractA computer model based on the finite element method has been applied to evaluate the effect of the parasitic area between contact and diffusion edges on end resistance measurements in four terminal Kelvin resistor structures. The model is then applied to Al/Ti/n+ Si contacts and a value of contact resistivity of Qc = 1.8×10−7.Ωcm2 is derived. For comparison, the use of a self-aligned structure to avoid parasitic effects is presented and the first experimental results obtained on Al/Ti/n+Si and Al/CoSi2/n+Si contacts are shown and discussed.

Study and Prediction of Bone Strength of Osteoporosis Model Based on Synchrotron Radiation

2021 ◽  
Author(s):  
Wanyu Li ◽  
Jun Xu ◽  
Shunan Zhang ◽  
Han Guo ◽  
Jianqi Sun ◽  
...  
Keyword(s):  
Finite Element ◽  
Synchrotron Radiation ◽  
Bone Strength ◽  
Lumbar Vertebrae ◽  
Bone Microstructure ◽  
Ovariectomized Rats ◽  
Osteoporotic Bone ◽  
Mineral Density ◽  
Model Based ◽  
Osteoporosis Diagnosis

Abstract Background: As the gold standard for clinical osteoporosis diagnosis, bone mineral density has significant limitations in bone strength assessment and fracture risk prediction. The purpose of this study is to explore a new osteoporotic bone quality evaluation criteria from both diagnosis site selection and bone strength prediction. Methods: Ovariectomized rats with different intensity swimming therapy were investigated in this study. The lumbar vertebrae and femurs of all the rats were scanned by synchrotron radiation computed tomography. Bone microstructure analysis and finite element analysis were combined to obtain bone microstructure parameters and estimated bone strength. And the sensitivity of different skeletal sites to therapy was explored. An elastic network regression model was established to predict bone strength by integrating additional bone microstructure characteristics besides bone mass.Results: Histomorphometry analysis showed that swimming therapy could reduce the risk of osteoporosis of lumbar vertebrae and femur and suggested that the femur might be a more suitable site for osteoporosis diagnosis and efficacy evaluation than the lumbar vertebrae. The average coefficient of determination and average root mean squared error of our predictive model were 0.774 and 0.110. Bland-Altman analysis showed that our model could be a good alternative to the finite element method. Conclusions: The present study developed a machine learning model for prediction of bone strength of osteoporosis model based on synchrotron x-ray imaging and demonstrated that different skeletal sites had different sensitivity to therapy, which is of great significance for the early diagnosis of osteoporosis, the prevention of fractures and the monitoring of therapy.

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