Mechanical behaviors and failure modes of sandwich cylinders with square honeycomb cores under axial compression

2022 ◽  
Vol 172 ◽  
pp. 108868
Author(s):  
Zhi-jia Zhang ◽  
Yong-jing Wang ◽  
Lei Huang ◽  
Yue Fu ◽  
Zi-qiang Zhang ◽  
...  
Author(s):  
Bernardo A. Lejano

<p>Getting good lumber for housing construction is becoming difficult in the Philippines due to existing partial log ban. Although, the use of reinforced concrete is still the most popular in construction, an emerging alternative is the use of cold-formed steel (CFS). It is gaining popularity because of its high strength-to- weight ratio. However, information about the structural performance of locally-produced cold-formed steel is almost nonexistent. Although, design provisions are stipulated in the local Code, these are based on formulas developed abroad, hence the need to investigate these cold-formed steel. This study focuses on the C-section cold-formed steel, which is the most popularly used. The objective is to verify its performance when subjected to axial compression and flexure, both experimentally and computationally. For the computational part, the formulas stipulated in the National Structural Code of the Philippines were followed. For the experimental part, the cold-formed steel members were subjected to compression loads and flexural loads. Aside from usual sensors, high-speed cameras were used to capture the failure modes. For axial compression test, 80 specimens with different lengths and thicknesses were tested. For flexure, 24 specimens of back-to-back C-sections were subjected to 4-point bending test. Results showed the predicted strengths were well below the experimental values. In design, this means the use of Code-based formulas is conservative. Failure modes observed were torsional buckling and distortional buckling. Comparison of failure modes between experiment and computation shows 70% agreement for compression and 75% for flexure. Finite element method calculations were also done and were compared with experimental results.</p>


2019 ◽  
Vol 22 (8) ◽  
pp. 1895-1908
Author(s):  
Fangfang Wei ◽  
Zejun Zheng ◽  
Jun Yu ◽  
Yongquan Wang

Concrete filled double-steel-plate composite walls with shear studs, one type of steel–concrete–steel walls, are recently developed and have been used in high-rise buildings, for which fire safety is a big concern. In order to investigate the fire endurance of this new type of concrete filled double-steel-plate composite walls, three specimens with different axial compression ratios and different lengths and intervals of shear studs were tested under one-side ISO-834 standard fire to obtain the temperature distribution, deformation, and detailed failure modes. Each specimen consisted of a concrete filled double-steel-plate composite wall-body and two boundary columns. Moreover, finite-element-based numerical investigations were conducted to confirm and extend experimental findings. All the concrete filled double-steel-plate composite walls failed in compression–flexure mode with the local buckling at the compressive steel plate. The results indicate that the fire endurance of concrete filled double-steel-plate composite walls is significantly affected by the axial compression ratio, the eccentricity of the axial load, and the bond strength between shear studs and concrete. Axial compression ratio, defined as the ratio of axial compression to the nominal compressive capacity of concrete filled double-steel-plate composite walls, has both positive and negative effects on the fire endurance of concrete filled double-steel-plate composite walls. The axial load eccentricity toward the unexposed side is much more detrimental to the fire endurance of concrete filled double-steel-plate composite walls than the one toward the exposed side. In engineering practice, it is recommended that proper intervals (not greater than 300 mm) and lengths (not less than 40 mm) of the shear studs should be used to ensure the bond between concrete and steel plates.


2012 ◽  
Vol 166-169 ◽  
pp. 764-769
Author(s):  
Ruo Hui Qiang ◽  
Ming Zhou Su ◽  
Junfen Yang ◽  
Jinbo Cui

Four different types of full-scale slotted end plate (SEP) connection joints are tested to determine their failure modes and damage mechanisms under ultimate loading. Researches on mechanical behaviors of I-type, T-type, U-type and Groove SEP connection joints bearing compression are studied, which also analyze their force-displacement behaviors and developing processes of deformation and strain. The results show that the bearing capacities of I, grooved, T and U types SEP connections are increased gradually, which indicate the SEP’s type has great influence on the ultimate strength of joints. The instability of SEP is the main factor to cause the loss of bearing capacity of the connection, which is shown through the development of strain, that SEP enters into plastic stage and the other regions still are elastic.


2011 ◽  
Vol 255-260 ◽  
pp. 723-727
Author(s):  
Jian Wu Pan

Based on the experiment of timber circular columns made of pine and fir confined by carbon-aramid hybrid FRP (HFRP) sheets under axial compression, the failure modes, axial bearing capacities, peak compression strains were analyzed. The results showed that: Compared to the unconfined specimens, the axial bearing capacities and peak compression strains of the specimens confined by HFRP sheets were all improved. Axial bearing capacities of pine and fir specimens improved 6.6%~16.8% and 5.0%~16.9%,respectively. Peak compression strains of pine and fir specimens improved 8.9%~60.2% and 11.5%~56.8%, respectively.


2012 ◽  
Vol 170-173 ◽  
pp. 3220-3223 ◽  
Author(s):  
De Qiang Sun ◽  
Wen Ting Cao ◽  
Meng Cai

Mechanical behaviors of square honeycombs cores (SHCs) are investigated by using the finite element (FE) simulations under the in-plane dynamic crushing loadings. With the increasing impact velocities, different deformation modes are observed. The force-displacement curves include four regimes with distinct characteristics. The plateau stresses are calculated for the SHCs with different configuration parameters. The dynamic plateau stress is the sum of the static plateau stress and the dynamic enhancement due to the inertia effect. The static plateau stress is proportional to the relative density of SHCs. The dynamic enhancement stress is proportional to the square of impact velocity and the relation coefficient depends on the configuration parameters. The empirical formulas of dynamic plateau stress in terms of configuration parameters and impact velocity are given.


2012 ◽  
Vol 446-449 ◽  
pp. 3736-3739 ◽  
Author(s):  
De Qiang Sun ◽  
Miao Liu ◽  
Ying Xue Zhu

The mechanical behaviors of cissoidal hexagonal cores (CHCs) are investigated by using the finite element (FE) simulations under the in-plane quasi-static crushing loadings. The calculated deformation processes, response curves and values of plateau stress are presented in the forms of diagrams, force-displacement curves or data tables, respectively. The influences of ratio of cell wall thickness to edge length and expanding angle on the quasi-static plateau stress are discussed in detail. The empirical expressions of quasi-static plateau stress in terms of configuration parameters are given based on the FE simulation results.


2015 ◽  
Vol 1125 ◽  
pp. 94-99 ◽  
Author(s):  
Aldyandra Hami Seno ◽  
Eko Koswara ◽  
Hendri Syamsudin ◽  
Djarot Widagdo

This research was done to evaluate the bending behavior (load-deflection curve and failuremode) of sandwich structures using Tali Bamboo strips as sandwich skin material. Bending tests wereconducted on sandwich specimens with end grain balsa (3-point bending) and polypropylene (PP)honeycomb cores (4-point bending) to evaluate their bending behavior. From the test results,analytical and numerical models were developed to simulate the observed bending behavior. Themodels are able to simulate the pre-failure bending behavior and failure modes (core shear failure) ofthe specimens. It is also shown that for thin (length/thickness > 20) sandwiches the models are moreaccurate since shear effects are less prominent. With the obtained models a predictive comparison isdone between the PP and balsa cored specimens since the testing configuration for each type wasdifferent. The analysis results show that balsa cored specimens are able to withstand higher transversebending loads due to the higher shear strength of the balsa core. These prediction results are to beproven by specimen testing which is the subject of future research.


2011 ◽  
Vol 250-253 ◽  
pp. 3-9 ◽  
Author(s):  
Wei Zhou Zhong ◽  
Xi Cheng Huang ◽  
Zhi Ming Hao ◽  
Ruo Ze Xie ◽  
Gang Chen

The curves of stress versus strain along spruce wood axial, radial and tangential directions are gained by static compression experiments. Moisture content and density of the spruce wood are 12.72% and 413 kg/m3respectively. The results indicate that spruce compression process includes elastic, yield and compaction phases. Failure modes of spruce subjected to axial compression are fiber buckling and wrinkle. And failure modes under radial or tangential compression are wood fiber slippage and delamination. Axial compression yield strength is about nine times as that of radial and tangential compression. Radial and tangential compression yield strengths are almost equal. Energy absorption efficiency and ideality energy absorption efficiency of spruce along different loading directions are analyzed. And theory analytic solution to single wood cell buckling under axial compression is done. The obtained expression shows that the mean limit loading is relative to yield stress, cell structure dimension and wrinkle length for complete wrinkle cases.


2012 ◽  
Vol 517 ◽  
pp. 564-569
Author(s):  
Jin Song Fan ◽  
An Zhou ◽  
Li Hua Chen ◽  
Bing Kang Liu

Recycled concrete is a kind of new construction materials, and now received more and more attention from researchers and engineers, since its application in engineering projects can well cater to the increasing requirements of development for economic and environment-friendly society. Based on the pseudo static test of five recycled reinforcement concrete frame columns with different experimental axial compression ratios from 0.3 to 0.65, their failure modes, failure mechanism, hysteretic behavior, skeleton curves, bearing capacity, rigidity, ductility and energy dissipation capacity were discussed. Some possible influence factors and disciplines were also selected and analyzed. The study indicates that recycled reinforcement concrete frame columns in the case of relative low axial compression ratios usually exhibited similar and steady mechanical properties with common concrete columns. With the increase of axial compression ratio, its ductility and energy dissipation capacity are decreased and destruction forms tended to obvious brittle fracture, though its bearing capacity could slightly rise. The test results and analysis also manifest recycled concrete had expectative application potentials in most case.


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