Effect of strain rate on mechanical properties of the bamboo material under quasi-static and dynamic loading condition

The tensile behaviors of corroded steel bars are important in the capacity evaluation of corroded reinforced concrete structures. The present paper studies the mechanical behavior of the corroded high strength reinforcing steel bars under static and dynamic loading. High strength reinforcing steel bars were corroded by using accelerated corrosion methods and the tensile tests were carried out under different strain rates. The results showed that the mechanical properties of corroded high strength steel bars were strain rate dependent, and the strain rate effect decreased with the increase of corrosion degree. The decreased nominal yield and ultimate strengths were mainly caused by the reduction of cross-sectional areas, and the decreased ultimate deformation and the shortened yield plateau resulted from the intensified stress concentration at the nonuniform reduction. Based on the test results, reduction factors were proposed to relate the tensile behaviors with the corrosion degree and strain rate for corroded bars. A modified Johnson-Cook strength model of corroded high strength steel bars under dynamic loading was proposed by taking into account the influence of corrosion degree. Comparison between the model and test results showed that proposed model properly describes the dynamic response of the corroded high strength rebars.

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Effect of Alkaline Treatment on Sawdust Reinforced High Density Polyethylene Composite under Wide Strain Rate

Materials Science Forum ◽

10.4028/www.scientific.net/msf.840.103 ◽

2016 ◽

Vol 840 ◽

pp. 103-107 ◽

Cited By ~ 2

Author(s):

Haliza Jaya ◽

Mohd Firdaus Omar ◽

Hazizan Md Akil ◽

Zainal Arifin Ahmad ◽

Nik Noriman Zulkepli

Keyword(s):

Surface Roughness ◽

Strain Rate ◽

Dynamic Loading ◽

High Density Polyethylene ◽

Split Hopkinson Pressure Bar ◽

Alkali Treatment ◽

Testing Machine ◽

High Density ◽

Rate Condition ◽

Static And Dynamic Loading

In this study, the alkali treatment of sawdust using different concentration of sodium hydroxide (NaOH) is performed. The purpose of this treatment is to improve the filler-matrix compatibility, thus, enhance the properties of tested specimens under various strain rate condition. The outcome shows the alkali treated sawdust did improve its surface roughness through reduction of sawdust diameter. With this increasing of surface roughness, it will enhance the compatibility between sawdust filler and HDPE matrix. For comparison purpose, the treated and untreated sawdust filler were reinforce in High Density Polyethylene (HDPE) matrix and have been test under static and dynamic loading using Universal Testing Machine (UTM) and Split Hopkinson Pressure Bar (SHPB) apparatus. The results indicate that the stiffness and compression strength properties were improved on treated sawdust composites for both static and dynamic loading compare to untreated sawdust composites.

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