scholarly journals A Material Model for the Orthotropic and Viscous Behavior of Separators in Lithium-Ion Batteries under High Mechanical Loads

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4585
Author(s):  
Marian Bulla ◽  
Stefan Kolling ◽  
Elham Sahraei

The present study is focused on the development of a material model where the orthotropic-visco-elastic and orthotropic-visco-plastic mechanical behavior of a polymeric material is considered. The increasing need to reduce the climate-damaging exhaust gases in the automotive industry leads to an increasing usage of electric powered drive systems using Lithium-ion (Li-ion) batteries. For the safety and crashworthiness investigations, a deeper understanding of the mechanical behavior under high and dynamic loads is needed. In order to prevent internal short circuits and thermal runaways within a Li-ion battery, the separator plays a crucial role. Based on results of material tests, a novel material model for finite element analysis (FEA) is developed using the explicit solver Altair Radioss. Based on this model, the visco-elastic-orthotropic, as well as the visco-plastic-orthotropic, behavior until failure can be modeled. Finally, a FE simulation model of the separator material is performed, using the results of different tensile tests conducted at three different velocities, 0.1 mm·s−1, 1.0 mm·s−1 and 10.0 mm·s−1 and different orientations of the specimen. The purpose is to predict the anisotropic, rate-dependent stiffness behavior of separator materials in order to improve FE simulations of the mechanical behavior of batteries and therefore reduce the development time of electrically powered vehicles and consumer goods. The present novel material model in combination with a well-suited failure criterion, which considers the different states of stress and anisotropic-visco-dependent failure limits, can be applied for crashworthiness FE analysis. The model succeeded in predicting anisotropic, visco-elastic orthotropic and visco-plastic orthotropic stiffness behavior up to failure.

Author(s):  
Varatharajan Prasannavenkadesan ◽  
Ponnusamy Pandithevan

Abstract In orthopedic surgery, bone cutting is an indispensable procedure followed by the surgeons to treat the fractured and fragmented bones. Because of the unsuitable parameter values used in the cutting processes, micro crack, fragmentation, and thermal osteonecrosis of bone are observed. Therefore, prediction of suitable cutting force is essential to subtract the bone without any adverse effect. In this study, the Cowper-Symonds model for bovine bone was developed for the first time. Then the developed model was coupled with the finite element analysis to predict the cutting force. To determine the model constants, tensile tests with different strain rates (10−5/s, 10−4/s, 10−3/s, and 1/s) were conducted on the cortical bone specimens. The developed material model was implemented in the bone cutting simulation and validated with the experiments.


2018 ◽  
Vol 183 ◽  
pp. 02056
Author(s):  
Martin Rund ◽  
Martin Mašek ◽  
Jan Džugan ◽  
Pavel Konopík ◽  
Jiøí Janovec

The presented study deals with the FEM simulation of dynamic behaviour of U-profile crash under three point bent loading conditions verified by experimental investigations. The material ductile damage behaviour under wide strain rate region covering 0.001 – 1 000 s-1 was experimentally determined with the use of standard and micro tensile tests (M-TT). DIC systems were used for strain field measurements under quasi-static and dynamic loading conditions. Based on these experimental data, material model considering ductile damage was established in Abaqus/Explicit code. Additionally, also metallographic investigations were performed for the fracture behaviour description.


Author(s):  
B. Bal ◽  
K. K. Karaveli ◽  
B. Cetin ◽  
B. Gumus

Al 7068-T651 alloy is one of the recently developed materials used mostly in the defense industry due to its high strength, toughness, and low weight compared to steels. The aim of this study is to identify the Johnson–Cook (J–C) material model parameters, the accurate Johnson–Cook (J–C) damage parameters, D1, D2, and D3 of the Al 7068-T651 alloy for finite element analysis-based simulation techniques, together with other damage parameters, D4 and D5. In order to determine D1, D2, and D3, tensile tests were conducted on notched and smooth specimens at medium strain rate, 100 s−1, and tests were repeated seven times to ensure the consistency of the results both in the rolling direction and perpendicular to the rolling direction. To determine D4 and D5 further, tensile tests were conducted on specimens at high strain rate (102 s−1) and temperature (300 °C) by means of the Gleeble thermal–mechanical physical simulation system. The final areas of fractured specimens were calculated through optical microscopy. The effects of stress triaxiality factor, rolling direction, strain rate, and temperature on the mechanical properties of the Al 7068-T651 alloy were also investigated. Damage parameters were calculated via the Levenberg–Marquardt optimization method. From all the aforementioned experimental work, J–C material model parameters were determined. In this article, J–C damage model constants, based on maximum and minimum equivalent strain values, were also reported which can be utilized for the simulation of different applications.


2016 ◽  
Vol 6 (3) ◽  
pp. 20160005 ◽  
Author(s):  
C. G. Skamniotis ◽  
Y. Patel ◽  
M. N. Charalambides ◽  
M. Elliott

The study of oral processing and specifically cutting of the food piece during mastication can lead towards optimization of products for humans or animals. Food materials are complex biocomposites with a highly nonlinear constitutive response. Their fracture properties have not been largely investigated, while the need for models capable of predicting food breakdown increases. In this study, the blade cutting and the essential work of fracture (EWF) methodologies assessed the fracture behaviour of starch-based pet food. Tensile tests revealed rate-dependent stiffness and stress softening effects, attributed to viscoplasticity and micro-cracking, respectively. Cutting data were collected for 5, 10 and 30 mm s −1 sample feed rates, whereas the EWF tests were conducted at 1.7, 3.3 and 8.3 mm s −1 crosshead speeds corresponding to average crack speeds of 4, 7 and 15 mm s −1 , respectively. A reasonable agreement was achieved between cutting and EWF, reporting 1.26, 1.78, 1.76 kJ m −2 and 1.52, 1.37, 1.45 kJ m −2 values, respectively, for the corresponding crack speeds. These toughness data were used in a novel numerical model simulating the ‘first’ bite mastication process. A viscoplastic material model is adopted for the food piece, combined with a damage law that enabled predicting fracture patterns in the product.


2007 ◽  
Vol 336-338 ◽  
pp. 517-520 ◽  
Author(s):  
Xiang Ming He ◽  
Wei Hua Pu ◽  
Fang Hui Zhao ◽  
Jie Rong Ying ◽  
Chang Yin Jiang ◽  
...  

Spherical LiNi0.8Co0.2O2 powders with particle size of 8~10μm were prepared based on controlled crystallization, and coated with Al2O3 by Al(OH)3 sol, that was prepared from Al(NO3)3 and NaOH, at first time. SEM, XRD and surface element analysis showed that the nano-sized Al2O3 was coated uniformly on the surface of LiNi0.8Co0.2O2 powder. At 25 °C, the initial discharge capacity decreased from 160 to 149 mAh g-1 after coating of Al2O3. The initial discharge capacity decreased from 168 to 163 mAh g-1 after coating of Al2O at 55 °C. After coating of Al2O3, the capacity retentions increased from 83.8% to 92.6% at the 50th cycle at 25°C, and from 36.3% to 90.8% at the 10th cycle at 55°C. This paves effective way to improve the performance of LiNi0.8Co0.2O2 material for rechargeable lithium ion batteries.


2019 ◽  
Vol 9 (14) ◽  
pp. 2851 ◽  
Author(s):  
Up Huh ◽  
Chung-Won Lee ◽  
Ji-Hun You ◽  
Chan-Hee Song ◽  
Chi-Seung Lee ◽  
...  

In this study, computational simulations and experiments were performed to investigate the mechanical behavior of the aorta wall because of the increasing occurrences of aorta-related diseases. The study focused on the deformation and strength of porcine and healthy human abdominal aortic tissues under uniaxial tensile loading. The experiments for the mechanical behavior of the arterial tissue were conducted using a uniaxial tensile test apparatus to validate the simulation results. In addition, the strength and stretching of the tissues in the abdominal aorta of a healthy human as a function of age were investigated based on the uniaxial tensile tests. Moreover, computational simulations using the ABAQUS finite element analysis program were conducted on the experimental scenarios based on age, and the Holzapfel–Gasser–Ogden (HGO) model was applied during the simulation. The material parameters and formulae to be used in the HGO model were proposed to identify the failure stress and stretch correlation with age.


2016 ◽  
Vol 08 (05) ◽  
pp. 1650062
Author(s):  
Yingfeng Liu ◽  
Qiong Rao ◽  
Ming Chen ◽  
Xiongqi Peng ◽  
Shaoqing Shi

Air cushion is an important packaging material with admirable cushion property in protecting articles from damage. Polymer membrane in air cushion renders a highly nonlinear elastic and rate dependent mechanical behavior in experimental tensile test. A visco-hyperelastic constitutive model for a polymer membrane of an air cushion is developed by additively decomposing its mechanical response into a hyperelastic portion and a viscoelastic portion. Material parameters are consecutively obtained by matching experimental data of static and dynamic uni-axial tensile tests of the membrane, respectively. Compression test of a single air column of the air cushion is conducted as a means of validation on the proposed constitutive model. By comparing simulation results with experimental data, it is shown that the proposed visco-hyperelastic model can properly characterize the mechanical behavior of the air cushion packaging material. The model can be applied to evaluate cushion performance of air cushions and their optimum design.


1998 ◽  
Vol 120 (4) ◽  
pp. 398-405 ◽  
Author(s):  
J. W. Tedesco ◽  
C. A. Ross

This paper summarizes the results of a comprehensive experimental study to quantify the effects of strain rate on concrete compressive and tensile strengths. Direct compression and splitting tensile tests were conducted at quasi-static rates (between 10−7/s and 10−5/s) in a standard MTS machine to establish the “static” properties. These same tests were conducted at high strain rates (between 10−1/s and 103/s) on a split-Hopkinson pressure bar (SHPB) to determine the dynamic material properties. A statistical analysis was performed on the data and strain-rate-dependent constitutive equations, both for compression and tension, were developed. These constitutive equations were subsequently employed to modify an existing quasi-static, nonlinear concrete material model.


2014 ◽  
Vol 566 ◽  
pp. 474-479 ◽  
Author(s):  
Kunio Takekoshi ◽  
Kazukuni Niwa

High-speed tensile tests were carried out to investigate strain rate effect on both yield stress and failure strain using ASTM D1822 Type-S specimens made of polycarbonate. Based on test results, parameters for a material model suitable for polymers are determined, and numerical analysis is carried out to simulate test results. The material model is used to simulate tensile test using a dog-bone specimen and Charpy test other than the tensile test of Type-S specimens. It is found that good predictions can be obtained when rate dependent material parameters are used. Further, the high-speed tensile test considered in the present study is suitable for selection of parameters for material modeling of polymers for impact analysis.


2011 ◽  
Vol 50-51 ◽  
pp. 599-604 ◽  
Author(s):  
X.Y. Kou ◽  
S.T. Tan ◽  
Hod Lipson

Driven by the wide range of new material properties offered by multi-material 3D printing, there is emerging need to create predictive material models for these materials. A data driven process for estimating nonlinear material model is presented in this paper. In contrast with classical methods which derive the engineering stress-strain relationship assuming constant cross-section area and fixed length of a specimen, the proposed approach takes full advantage of 3D geometry of the specimen to estimate the material models. Give a hypothetical material model, virtual tensile tests are performed using Finite Element Analysis (FEA) method, and the parameters of the material model are estimated by minimizing the discrepancies of the virtual responses and the experimental results. The detailed material models, numerical algorithms as well as the optimization approaches are presented and finally preliminary results are offered.


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