scholarly journals Evaluation of Hoffman and Xia plasticity models against bi-axial tension experiments of planar fiber network materials

Author(s):  
Mossab Alzweighi ◽  
Rami Mansour ◽  
Johan Tryding ◽  
Artem Kulachenko
2010 ◽  
Vol 452-453 ◽  
pp. 73-76
Author(s):  
Li Hong Yang ◽  
Guang Ping Zou ◽  
Xue Yi Zhang

Torsion experiments should be adopted to characterize large strain elasto-plastic behavior of material instead of traditional uni-axial tension experiments due to the plastic stability of specimen in torsion deformation. Study on spins and deformation rate in finite torsion deformation is the key to determine the material parameters by torsion experiments and understand the finite deformation characteristics of material. In this paper, five spins and deformation rate in torsion deformation with solid circular shafts are investigated in cylinder coordinates. The expressions of the deformation rate and spins, namely the material spin, the relative spin, the spin of the frame of the deformation rate, logarithmic spin and instantaneous spin considering the effect of stress, are deduced by analyzing the finite torsion deformation. The comparisons are made among all spins obtained in this paper. The results obtained in this paper are the basis of analyzing the large strain constitutive relationship based on torsion experiments with solid circular shafts.


2018 ◽  
Vol 84 (12) ◽  
pp. 61-67
Author(s):  
V. A. Eryshev

The mechanical properties of a complex composite material formed by steel and hardened concrete, are studied. A technique of operative quality control of new credible concrete and reinforcement, both in laboratory and field conditions is developed for determination of the strength and strain characteristics of materials, as well as cohesion forces determining their joint operation under load. The design of the mobile unit is presented. The unit provides a possibility of changing the direction of loading and testing the reinforced element of the given shape both for tension and compression. Moreover, the nomenclature of testing equipment and the number of molds for manufacturing concrete samples substantially decrease. Using the values of forcing resulting in concrete cracking when the joint work of concrete and reinforcement is disrupted the values of the inherent stresses and strains attributed to the concrete shrinkage are determined. An analytical relationship between the forces and deformations of the reinforced concrete sample with central reinforcement is derived for axial tension and compression, with allowance for strains and stresses in the reinforcement and concrete resulted from concrete shrinkage. The results of experimental studies are presented, including tension diagrams and diagrams of developing axial deformations with an increase in the load under the central loading of the reinforced elements. A methodology of accounting for stresses and deformations resulted from concrete shrinkage is developed. The applicability of the derived analytical relationships between stresses and deformations on the material diagrams to calculations of the reinforced concrete structures in the framework of the deformation model is estimated.


2021 ◽  
Vol 1162 (1) ◽  
pp. 012016
Author(s):  
M Surianinov ◽  
D Kirichenko ◽  
I Korneieva ◽  
S Neutov

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Yan Wei ◽  
Guixin Zhu ◽  
Zifan Zhao ◽  
Chengcheng Yin ◽  
Qin Zhao ◽  
...  

AbstractMineralized tissue regeneration is an important and challenging part of the field of tissue engineering and regeneration. At present, autograft harvest procedures may cause secondary trauma to patients, while bone scaffold materials lack osteogenic activity, resulting in a limited application. Loaded with osteogenic induction growth factor can improve the osteoinductive performance of bone graft, but the explosive release of growth factor may also cause side effects. In this study, we innovatively used platelet-rich fibrin (PRF)-modified bone scaffolds (Bio-Oss®) to replace autograft, and used cytokine (BMP-2) to enhance osteogenesis. Encouragingly, this mixture, which we named “Autograft Mimic (AGM)”, has multiple functions and advantages. (1) The fiber network provided by PRF binds the entire bone scaffold together, thereby shaping the bone grafts and maintaining the space of the defect area. (2) The sustained release of BMP-2 from bone graft promoted bone regeneration continuously. (3) AGM recruited bone marrow mesenchymal stem cells (BMSCs) and promote their proliferation, migration, and osteogenic differentiation. Thus, AGM developed in this study can improve osteogenesis, and provide new guidance for the development of clinical bone grafts.


Author(s):  
Xiaowei Cheng ◽  
Haoyou Zhang

AbstractUnder strong earthquakes, reinforced concrete (RC) walls in high-rise buildings, particularly in wall piers that form part of a coupled or core wall system, may experience coupled axial tension–flexure loading. In this study, a detailed finite element model was developed in VecTor2 to provide an effective tool for the further investigation of the seismic behaviour of RC walls subjected to axial tension and cyclic lateral loading. The model was verified using experimental data from recent RC wall tests under axial tension and cyclic lateral loading, and results showed that the model can accurately capture the overall response of RC walls. Additional analyses were conducted using the developed model to investigate the effect of key design parameters on the peak strength, ultimate deformation capacity and plastic hinge length of RC walls under axial tension and cyclic lateral loading. On the basis of the analysis results, useful information were provided when designing or assessing the seismic behaviour of RC slender walls under coupled axial tension–flexure loading.


2021 ◽  
Vol 111 ◽  
pp. 102637
Author(s):  
Zhan-Feng Chen ◽  
Wen Wang ◽  
He Yang ◽  
Sun-Ting Yan ◽  
Zhi-Jiang Jin

Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 489
Author(s):  
Hyun-Seok Jang ◽  
Min-Soo Moon ◽  
Byung-Hoon Kim

Demand for wearable and portable electronic devices has increased, raising interest in electronic textiles (e-textiles). E-textiles have been produced using various materials including carbon nanotubes, graphene, and graphene oxide. Among the materials in this minireview, we introduce e-textiles fabricated with graphene oxide (GO) coating, using commercial textiles. GO-coated cotton, nylon, polyester, and silk are reported. The GO-coated commercial textiles were reduced chemically and thermally. The maximum e-textile conductivity of about 10 S/cm was achieved in GO-coated silk. We also introduce an e-textile made of uncoated silk. The silk-based e-textiles were obtained using a simple heat treatment with axial tension. The conductivity of the e-textiles was over 100 S/cm.


2012 ◽  
Vol 27 (2) ◽  
pp. 318-328 ◽  
Author(s):  
Svetlana Borodulina ◽  
Artem Kulachenko ◽  
Mikael Nygårds ◽  
Sylvain Galland

Abstract We have investigated a relation between micromechanical processes and the stress-strain curve of a dry fiber network during tensile loading. By using a detailed particle-level simulation tool we investigate, among other things, the impact of “non-traditional” bonding parameters, such as compliance of bonding regions, work of separation and the actual number of effective bonds. This is probably the first three-dimensional model which is capable of simulating the fracture process of paper accounting for nonlinearities at the fiber level and bond failures. The failure behavior of the network considered in the study could be changed significantly by relatively small changes in bond strength, as compared to the scatter in bonding data found in the literature. We have identified that compliance of the bonding regions has a significant impact on network strength. By comparing networks with weak and strong bonds, we concluded that large local strains are the precursors of bond failures and not the other way around.


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