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1

Simulation and experimental study of the thermal characteristics of a high-speed motorized spindle

Zhang Wei, Jiang Huaqiao

Archives of Thermodynamics

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2024

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Vol. 45, no 1

17--22

EN

Based on the finite element simulation software ANSYS Workbench, this study reports the thermal characteristics of a high-speed motorized spindle. The temperature field distribution and axial thermal deformation of the motorized spindle are then detected on an experimental platform. A comparison between the experimental and simulation results revealed the temperature rise of the motorized spindle during the working process. Under steady-state conditions of the working motorized spindle, the temperatures of the front bearing, rear bearing and stator were determined as 20°C, approximately 30°C and 25°C, respectively. The axial thermal elongation of the motorized spindle is approximately 10 μm

2

Modelling the age-related decrease in ballistic limit velocity of polycarbonate vision panels using a Johnson-Cook material model coupled with variable failure criteria

Uhlmann Eckart, Polte Mitchel, Bergström Nils, Le Vu Ninh

Journal of Machine Engineering

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2023

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Vol. 23, No. 3

86--97

EN

Machine tools are equipped with polycarbonate vision panels that allow the operator to observe the machining process and protect him from ejected fragments. Adequate protection is demonstrated by impact tests. However, polycarbonate is subject to aging processes, which diminish the protective performance of such panels. This paper presents an approach for modelling aging effects on the ballistic limit velocity of polycarbonate using Finite Element simulations. A Johnson-Cook material model in conjunction with variable failure criteria was used for the simulations. Aging effects on the ballistic limit velocity were included in the model by adjusting the failure criteria. Material parameters and failure criteria were derived from experimental impact and tensile tests on unaged and aged polycarbonate specimen. The numerical results predict the ballistic limit velocity with a maximum deviation of 0.98%. The model provides a more in-depth understanding of the aging effects on the safety performance of polycarbonate vision panels.

3

Deformation behavior and mechanical properties of 5052-O aluminum alloy joints formed by high-speed clinching

Huang Changqing, Ji Yanan, Cui Xiaohui, Sun Xiaoming, Wang Shu, Yang Huan

Archives of Civil and Mechanical Engineering

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2023

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Vol. 23, no. 3

art. no. e152, 2023

EN

In this paper, the high-speed clinching named electromagnetic-driven clinching (EMDC) method was adopted and analyzed by experiment, numerical simulation and theoretical calculation. The deformation behavior and mechanical properties of 5052-O EMDC joints have been investigated. The result showed that the punch speed can reach 3 m/s, The maximum strain rate of the EMDC process can reach 6000 s−1. The EMDC process can be divided into deep drawing, interlocking, and unloading stages. The neck thickness tN changes mainly in deep drawing stage. The interlock value tU changes mainly in interlocking stage. The discharge voltage level can precisely control the formation of the joint. With the increase of the discharge voltage, the tN did not change significantly, while the tU increased and mechanical properties of the joint gradually improved. When the discharge voltage was 3.4 kV, the shear and tensile joint strength were 1571 N and 746 N, respectively. The simulation results and the theoretical calculations were in good agreement with the experimental results.

4

Thermal error modeling of spindle and dynamic machining accuracy reliability analysis of CNC machine tools based on IA and LHSMC

Zhang Ziling, Feng Shuo, Ding Yan, Mei Xiao, Tao Zhiqiang

Eksploatacja i Niezawodność

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2022

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Vol. 24, no. 1

100--113

EN

Machining accuracy reliability as a key index of CNC machine tools is seriously influenced by the geometric and thermal errors. In the paper, a spindle unit thermal error modeling and machining accuracy reliability analysis method is proposed. By analyzing the heat generation mechanism, a thermal error model was developed to describe the thermal deformation of the electric spindle. Based on the immune algorithm (IA), the heat generation power and the heat transfer coefficient were optimized, and the thermal error was obtained by finite element thermal-mechanical coupling. By adopting the multi-body system theory (MBS), a dynamic machining accuracy model was put forward including the geometric and thermal errors. Based on the Latin hypercube sampling Monte Carlo method (LHSMC), a machining accuracy reliability analysis method was proposed to characterize the machining accuracy reliability considering the geometric and thermal errors. The method was employed to a machine tool, and the experimental results indicate the verification and superiority of the method.

5

Dynamic reliability evaluation of buried corroded pipeline under rockfall impact

Wang Yifei, Xie Mingjiang, Su Chun

Eksploatacja i Niezawodność

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2022

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Vol. 24, no. 2

275--288

EN

Load impact, such as the rockfall, may bring significant threats to the integrity management of pipeline. This study is intended to evaluate the reliability of buried pipeline under rockfall impact, and so as to reduce the possible failure and unnecessary downtime. Firstly, the dynamic response of the buried pipeline under load is analyzed by Euler Bernoulli foundation beam. After that, the process of rockfall impact on buried corroded pipeline is simulated with nonlinear finite element method. Furthermore, the influence of rockfall’s parameters (including rockfall mass, impact velocity, impact position, etc.) on the pipeline’s equivalent stress is quantitatively analyzed. Eventually, a time-varying reliability model is established to calculate the failure probability. The results indicate that the mass and velocity of the rockfall have obvious influence on the pipeline’s failure probability, and the change of impact’s position has small influence. The proposed method can provide a theoretical reference for the design and maintenance of buried pipeline.

6

Studying the Behavior of the C45 Material when Changing the Tool Geometry Using the Finite Element Method

Pop Alina Bianca, Sandu Andrei Victor, Sachelarie Adrian, Țîțu Aurel Mihail

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 2

653--659

EN

Machining with tool that have cutting edge radius provides components with high fatigue strength, microhardness of a large surface layer and plastic deformation. Finite element simulations of the cutting process give a better knowledge of the chip generation phenomenon, heat generation in the machining area, stress and temperature field results. This study emphasizes the true importance of the mathematical model that underlies the shape of the tool in the pre-processing steps of finite element analysis. The argument is that its achievement and definition depend on the network difficulty. This research purpose is to perform simulations series of orthogonal machining with different radius and depth of cut. In this way, conclusions on the impact of these variations on the whole cutting process were drawn. The finite element application used is Deform 2D, the Lagrange incremental method and the Johnson-Cook material model. The temperature distribution, stress distribution, von Mises stress distribution, effects on specific tool pressure and wear, and fluctuations in the cutting resistance of the tool tip and C45 workpiece were analyzed.

7

Research on a novel hybrid shielding structure of magnetic coupler for inductive power transfer system

Liu Yun Rui, Wang Chunfang, Xia Dongwei, Yue Rui

Archives of Electrical Engineering

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2021

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Vol. 70, nr 1

129--143

EN

With the development of wireless power transfer technology, more and more attention has been paid to its electromagnetic safety. In this paper, a novel hybrid shielding structure composed of the innermost fan-shaped ferrite, the interlayer nanocrystalline stripand the outermost aluminum foil is proposed to shield the electromagnetic field of the inductive power transfer system. Eight structure parameters of the proposed shielding areoptimized by finite element simulation, in order to reduce the magnetic leakage of the system and improve the utilization rate of shielding materials. In addition, the proposed structure is compared with two types of typical double-layer hybrid shielding from the perspectives of the weight, the coupling coefficient and the magnetic flux leakage. Both simulation and experiment results show that the cost and weight of the proposed shield are about 60% lower than the traditional disk shield. More over, the shielding layer proposed in this paper can not only effectively reduce the magnetic flux leakage of the system, but also maintain a high coupling coefficient.

8

Multiphysics simulation and shed structure optimization of catenary icing insulator

Wang Sihua, Wang Junjun, Zhou Lijun, Chen Long, Zhao Lei

Archives of Electrical Engineering

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2021

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Vol. 70, nr 3

675--688

EN

It is not easy to make the insulators of the railway catenary for the dry and cold environment of the icy Qinghai-Tibet plateau, without causing serious ice-related flashover accidents. To study the operating status of catenary icing insulators, a two-dimensional icing model of catenary cantilever insulators was established based on the winter environmental characteristics of the Golmud station on the Qinghai-Tibet Railway. Compared different directions of ice growth, the spatial electric field distribution, and surface temperature distribution characteristics of icing insulators were analyzed by multi-physical field coupling simulation. The results show that as the thickness of the ice layer increases and the length of the icicle increases, the field intensity of the insulator gradually increases, and the surface temperature continues to rise. When the ice edge grows vertically downward, the electric field intensity of the insulator is the smallest, and the electric field intensity is the largest when the ice edge grows horizontally. Although the surface temperature of the insulator will rise with the increase of icing degree, it is lower than the freezing point and will not have a great impact on insulation performance. Secondly, when the cantilever insulator is arranged obliquely, the increase in the inclination angle will cause the electric field to increase and the temperature to rise slightly, so the inclination angle of the oblique cantilever should be reduced as much as possible during installation. Finally, the insulator with better insulation performance is obtained by optimizing the structure of the flat cantilever insulator.

9

Prediction of the bending and out-of-plane loading effects on formability response of the steel sheets

Peng Deping, Chen Shun, Darabi Roya, Ghabussi Aria, Habibi Mostafa

Archives of Civil and Mechanical Engineering

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2021

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Vol. 21, no. 2

563--575

EN

Failure in sheet metal forming can occur by necking, fracture or wrinkling. By using a forming limit diagram (FLD) as a powerful tool to prevent sheets metal failures in the forming process, provides parameters controlling throughout forming. There are different developed methods for predicting FLDs, which estimate sheet metal forming strains limits. Assessment of FLD estimation reveals that there is a dependency between the effect of several factors containing normal stress, shear stress, sheet thickness, mechanical properties, metallurgical properties, yield function, strain path, and bending with formability. In this research, the effects of bending via two finite element models are investigated. In the first method, the out-of-plane deformation is applied by increasing punch displacement to study the effects of bending. In the second method, the effect of bending is investigated via changing punch diameter (25, 50, 70 and, 100 mm). The Marciniak–Kuczynski (M–K) theory is used to predict the time of localized necking in finite element simulations. Furthermore, a novel method for the determination of the inhomogeneity coefficient is presented in M–K model to simulate the groove width for M–K model. To verify finite element simulation results, Nakazima tests with 50 and 100 mm punch diameters were done as experimental studies. The comparison of experimental results and finite element analysis illustrates that the increasing bending or the out-of-plane loading can improve formability. At the end, the effect of bending on FLD is reported as an equation based on minor and major strains.

10

Computational modelling of foot orthosis for midfoot arthritis: a Taguchi approach for design optimization

Zhang Haowei, Liv Miko Lin, Yang Junyan, Cheung James Chung-Wai, Sun Wanju, Wong Duo Wai-Chi, NI Ming

Acta of Bioengineering and Biomechanics

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2020

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Vol. 22, no. 4

75--83

EN

Evaluation of the internal biomechanics of the foot-and-ankle complex is challenging for the prescription of orthosis particularly for midfoot arthritis patients in which the joint condition is crucial. Methods: Using computational modeling and design optimization techniques, the objective of this study was to compare the biomechanical functions among different combinations of design factors using computer simulation. A finite element foot model was reconstructed from a midfoot arthritis patient. Orthotic designs with 3 levels for each of the 3 design factors (arch height, lateral wedge angle, and insole stiffness) contributed to 9 configurations using a fractional factorial design were tested. Results: An increase in peak plantar stress of the midfoot was facilitated by a medium arch height and wedge angle, and stiffest insole material, notwithstanding the combination neither reduced the peak plantar stress of other foot regions nor was consistent with the combination that minimized the stress of the articular cartilage. Conclusions: Insole with high arch (H = 30 mm), low stiffness (E = 1.0 MPa), and medium wedge angle (A = 5) could minimize the stress of the cartilage at the arthritic joint (primary outcome) and could be beneficial to the patients. Also, insole stiffness predominantly influenced cartilage stress. However, secondary outcomes including the stress of the navicular and medial cuneiform and the regional plantar stress did not produce the same solution. Future studies can consider a patient-specific loading profile to further the investigation on the stabilizing effect and the attenuation of load transfer induced by the insole.

11

Research on energy absorption properties of open-cell copper foam for current collector of Li-ions

Chen Jian, Li Xiongfei, Li Wei, Li Cong, Xie Baoshan, Dai Shuowei, He Jian-Jun, Ren Yanjie

Materials Science Poland

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2019

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Vol. 37, No. 1

8--15

EN

Quasi-static uniaxial compressive tests of open-cell copper (Cu) foams (OCCF) were carried out on an in-situ bi-direction tension/compress testing machine (IBTC 2000). The effects of strain rate, porosity and pore size on the energy absorption of open-cell copper foams were investigated to reveal the energy absorption mechanism. The results show that three performance parameters of open-cell copper foams (OCCF), involving compressive strength, Young modulus and yield stress, increase simultaneously with an increase of strain rate and reduce with increasing porosity and pore size. Furthermore, the energy absorption capacity of OCCF increases with an increase of porosity and pore size. However, energy absorption efficiency increases with increasing porosity and decreasing pore size. The finite element simulation results show that the two-dimensional stochastic model can predict the energy absorption performance of the foam during the compressive process. The large permanent plastic deformation at the weak edge hole is the main factor that affects the energy absorption.

12

Numerical modeling of uncertainty in acoustic propagation via generalized Polynomial Chaos

Dammak Khalil, Koubaa Sana, Elhami Abdelkhalak, Walha Lassaad, Haddar Mohamed

Journal of Theoretical and Applied Mechanics

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2019

|

Vol. 57 nr 1

3--15

EN

This work aims at increasing the performance prediction for acoustic propagation systems that will operate in the presence of the inevitable parameters uncertainty. In the present contribution, the finite element method is applied to solve an acoustic problem described by the Helmholz equation when the geometric and material properties present uncertainty. The influence of the uncertainty of physical parameters on the pressure field is discussed. The results using the polynomial chaos expansion method are compared with Monte Carlo simulations. It is show that uncertainty levels in the input data could result in large variability in the calculated pressure field in the domain.

13

Structural response of multilayered aluminum and steel specimens subjected to high strain rate loading conditions

Iqbal D., Tiwari V.

Journal of Theoretical and Applied Mechanics

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2018

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Vol. 56 nr 4

1139--1151

EN

Series of experiments and a detailed computational analysis has been performed to investigate the high strain rate behaviour of homostacked Al 6063-T6 and IS 1570 alloys. Split Hopkinson pressure bar technique was utilized to study the effect of high rate loading on the stress strain relationship of single, double, tri and quad layered/stacked specimens. Three different specimen aspect ratios 1, 0.75 and 0.5 were also evaluated for different strain rates. A 2 mm thick pulse shaper was employed in achieving dynamic stress equilibrium, a near constant strain rate and a high rise time as per requirements. After analyzing the results from the experiments it was observed that single and halved specimens showed a close match in both the elastic and plastic regions for aluminium alloy as well as for steel. In the case of Al 6063-T6, a nearly bi-linear nature of the constitutive curve was observed for single and halved specimens, which transformed into near tri-linear nature for tri and quad stacked specimens. The dynamic numerical analysis showed a good agreement between the numerical and experimental results for a single and halved specimen in the case of Al alloy. For steel, a close correlation was observed for all the four cases.

14

The Choice of Initial Conditions and of Solution in the Problem of Efficiency Increase of Pipes Calibration on a Mandrel

Salikhyanov D., Bogatov A., Dyja H.

Archives of Metallurgy and Materials

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2018

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Vol. 63, iss. 2

739--742

EN

This research work is devoted to the theoretical study of the pipe calibration on a mandrel. The aim of the study is to improve the precision of the calibrated pipes. As the paper shows, it is advisable to apply different methods of research depending on the purpose of the study of metal forming processes: mathematical, computer or physical simulation. Analytical review of existing mathematical models of the pipes calibration on a mandrel showed that the set of assumptions adopted in the mathematical modeling does not allow assessing the precision of the pipes during calibration. Therefore, finite-element method simulation package was used for this research. Research method and pipes precision index were developed on the basis of the computer simulation using Deform-3D package. The investigations have allowed us to get the dependence of the pipe precision on technological factors and to identify the root cause of reduced efficiency calibration – extrafocal deformation.

15

Investigation of Plug Rolling with Stub Mandrel Using the Finite Element Method

Pavlov D., Bogatov A., Pavlova E., Dyja H.

Archives of Metallurgy and Materials

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2018

|

Vol. 63, iss. 3

1083--1086

EN

The study proposed the model of "guide mark" defects formation on the internal surface of pipes, produced on PRM mills of PRP–140. The research of pipe forming at plug rolling mill with stub mandrel has been carried out; regularities of the dimens ionless parameters characterizing the deformation of the gap release, depending on the reduction ratio, were determined. The model of "guide mark" defect formation on the internal surface of the pipe has been proposed. This allows for lesser wall thickness variation o f rough tubes. It has been shown that, when using dioctahedral pass designs in comparison with hexagonal pass designs the proportion of displaced volume along the pipe axis is greater but the value is lower; thereby, the risk of "guide mark" defect forming is red uced.

16

Damage characterization of aluminum 2024 thin sheet for different stress triaxialities

Majzoobi G. H., Kashfi M., Bonora N., Iannitti G., Ruggiero A., Khademi E.

Archives of Civil and Mechanical Engineering

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2018

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Vol. 18, no. 3

702--712

EN

Due to its attractive mechanical properties, aluminum 2024 is widely used in aircraft manufacturing industries, especially as fiber metal laminates, such as GLARE. In the present work, a series of experiments for different stress triaxialities are used to study the ductile damage of Al 2024 considering continuum damage mechanics (CDM). Stress triaxiality is produced using notched specimens. The main objective of the present study is to predict the local equivalent plastic strain to fracture and introducing a relation which describes the effect of stress triaxiality factor (TF) on it in the medium range of stress triaxiality. Hence, a nonlinear damage model is utilized for Al 2024 and its parameters are determined by an experimental/numerical/optimization procedure using tensile test on plain specimens. The experiments showed that for large notch specimens (Al-NL) and medium notch samples (Al-NM) fracture started from the center of the notch root of the specimens, whereas for small notched specimens (Al-NS) the failure initiated from the notch root surface. Finite element simulations are performed using the presented nonlinear damage model and are compared with the experimental data. Results show that the proposed damage model can predict the damage evolution for different stress triaxialities.

17

Three-dimensional biomechanical modeling and simulation of trephine cutting cornea for keratoplasty

Su P., Lu D., Deng S., Zhang L., Hao Y., Yang Y.

Acta of Bioengineering and Biomechanics

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2018

|

Vol. 20, no. 2

23--33

EN

Trephination is one of the basic operations of keratoplasty, and the biomechanical mechanism of the operation can be revealed based on three-dimensional modeling and simulation of trephine cutting cornea. Methods: Based on the analysis of the physical and biomechanical characteristics of corneal trephination, a three-dimensional numerical model of corneal trephination is built, where the cornea can be simplified to two layers structure including stroma and epithelium, and the trephine cuts the cornea under the vertical motion load and the rotational motion load. A three-dimensional failure criterion of corneal material is proposed based on the yield strength theory. On this basis, trephination simulation is carried out, and the units of corneal material are removed from the model when they meet the defined failure criterion. Results: Under the given parameters including the velocity, the angle and the angular velocity, the trephine force curves, include the linear cutting force and the rotary cutting force are obtained, and show the change of the forces with displacement during the process of trephination simulation. The maps of the equivalent stress show the destruction and deformation of the cornea. Then, the experiment of robotic trephination is carried out under the same parameters and the effectiveness of the simulation is evaluated. Conclusions: Based on mechanics theory and finite element method, the process of trephine cutting cornea has been reproduced, and the interaction mechanism is revealed, which lays the foundation for the development of real-time simulation and virtual system of the corneal surgery.

18

Transient finite element simulation and microstructure evolution of AA2219 weld joint using gas tungsten arc welding process

Arunkumar S., Shrikrishna A. K., Paulraj S., Devakumaran K., Kumar S. R.

Advances in Science and Technology. Research Journal

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2016

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Vol. 10, nr 31

64--73

EN

In this study we focus on finite element simulation of gas tungsten arc welding (GTAW) of AA2219 aluminum alloy and the behavioral of the microstructure before and after weld. The simulations were performed using commercial COMSOL Multiphysics software. The thermal history of the weld region was studied by initially developed mathematical model. A sweep type meshing was used and transient analysis was performed for one welding cycle. The highest temperature noted was 3568 °C during welding. The welding operation was performed on 200×100×25 mm plates. Through metallurgical characterization, it was observed that a fair copper rich cellular (CRC) network existed in the weld region. A small amount of intermetallic compounds like Al2Cu is observed through the XRD pattern.

19

Factors affecting the mechanical properties of compact bone and miniature specimen test techniques: a review

Chittibabu V., Rao S. K., Rao G. P.

Advances in Science and Technology. Research Journal

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2016

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Vol. 10, nr 32

169--183

EN

This paper presents the review concerning mechanical properties of bone and the miniature specimen test techniques. For developing a realistic understanding of how factors such as moisture content, mineralization, age, species, location, gender, rate of deformation etc. affect the mechanical properties of bone, it is critical to understand the role of these factors. A general survey on existing research work is presented on this aspect. The essential features of miniature specimen test techniques are described, along with the application of small punch test method to evaluate the mechanical behavior of materials. The procedure for the determination of tensile and fracture properties, such as: yield strength, ultimate strength, ductility, fracture toughness etc. using small punch test technique have been described. The empirical equations proposed by various investigators for the prediction of tensile and fracture properties are presented and discussed. In some cases, the predictions of material properties have been essentially made through the finite element simulation. The finite element simulation of miniature specimen test technique is also covered in this review. The use of inverse finite element procedure for the prediction of uniaxial tensile constitutive behaviour of materials is also presented.

20

Modelling of textile composite reinforcements on the micro-scale

Döbrich O., Gereke T., Cherif C.

Autex Research Journal

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2014

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Vol. 14, no. 1

28--33

EN

Numerical simulation tools are increasingly used for developing novel composites and composite reinforcements. The aim of this paper is the application of digital elements for the simulation of the mechanical behaviour of textile reinforcement structures by means of a finite element analysis. The beneficial computational cost of these elements makes them applicable for the use in large models with a solution on near micro-scale. The representation of multifilament yarn models by a large number of element-chains is highly suitable for the analysis of structural and geometrical effects. In this paper, a unit cell generating method for technical reinforcement textiles, using digital elements for the discretization, is introduced.