Meso-scale modeling of size effect in eccentrically-loaded squared CFST columns: Influence of eccentricity and confinement effect

2021 ◽  
Vol 169 ◽  
pp. 108455
Author(s):  
Liu Jin ◽  
Lingling Fan ◽  
Xiuli Du
2021 ◽  
pp. 105678952110339
Author(s):  
Hongyong Jiang ◽  
Yiru Ren ◽  
Qiduo Jin

A novel synergistic multi-scale modeling framework with a coupling of micro- and meso-scale is proposed to predict damage behaviors of 2D-triaxially braided composite (2DTBC). Based on the Bridge model, the internal stress and micro damage of constituent materials are respectively coupled with the stress and damage of tow. The initial effective elastic properties of tow (IEEP) used as the predefined data are estimated by micro-mechanics models. Due to in-situ effects, stress concentration factor (SCF) is considered in the micro matrix, exhibiting progressive damage accumulation. Comparisons of IEEP and strengths between the Bridge and Chamis’ theory are conducted to validate the values of IEEP and SCF. Based on the representative volume element (RVE), the macro properties and damage modes of 2DTBC are predicted to be consistent with available experiments and meso-scale simulation. Both axial and transverse damage mechanisms of 2DTBC under tensile or compressive load are revealed. Micro fiber and matrix damage accumulations have significant effects on the meso-scale axial and transverse damage of tows due to multi-scale coupling effects. Different from existing meso-/multi-scale models, the proposed multi-scale model can capture a crucial phenomenon that the transverse damage of tow is vulnerable to micro fiber fracture. The proposed multi-scale framework provides a robust tool for future systematic studies on constituent materials level to larger-scale aeronautical materials.


Structures ◽  
2021 ◽  
Vol 34 ◽  
pp. 2996-3012
Author(s):  
Hongyuan Zhou ◽  
Houzhan Zhou ◽  
Xiaojuan Wang ◽  
Wanlin Cao ◽  
Tianyi Song ◽  
...  

2019 ◽  
Vol 196 ◽  
pp. 188-201 ◽  
Author(s):  
Yongli Ma ◽  
Mingyan Liu ◽  
Yuan Zhang

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Ying Guo ◽  
Yufen Zhang

This paper presented a comparative study of concrete-filled steel tubular (CFST) stub columns with three different confinement types from carbon fiber reinforced polymer (CFRP): outer circular CFRP, inner circular CFRP, and outer square CFRP. The compressive mechanism and physical properties of the composite column were analyzed firstly aiming at investigating the confinement effect of CFRP. Ultimate axial bearing capacity of these three CFRP-confined CFST columns was calculated based on Unified Theory of CFST and elastoplastic limit equilibrium theory, respectively. Meanwhile, the corresponding tests are adopted to validate the feasibility of the two calculation models. Through data analysis, the study confirmed the ultimate strength calculation results of the limit equilibrium method were found to be more reliable and approximate to the test results than those of Unified Theory of CFST. Then axial bearing capacity of the pure CFST column was predicted to evaluate the bearing capacity enhancement ratio of the three types of composite columns. It was demonstrated that the averaged enhancement ratio is 16.4 percent, showing that CFRP-confined CFST columns had a broad engineering applicability. Through a comparative analysis, this study also confirmed that outer circular CFRP had the best confinement effect and outer square CFRP did better than inner circular CFRP. The confinement effect of CFRP increased with the decrease of concrete strength, and it was proportional with relative proportions of CFRP and steel under the same concrete strength.


1999 ◽  
Vol 121 (2) ◽  
pp. 156-161
Author(s):  
Osamu Watanabe ◽  
Takayuki Kurata

Several plasticity phenomena display a size effect where the smaller the size is the stronger its response. This effect relates to the plastic gradients, appearing in plastically inhomogeneous material. The present paper describes results of an experimental meso-scale study using the specimens having rectangular cross section made of FCC polycrystal of pure Aluminum and OFHC Copper under the tensile or compressive loading. Experimental measurements are carried out to investigate thickness effect and grain size effect in connection with size effect, and the internal mechanism of plastic flow in the specimens is also discussed.


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