Static and Dynamic Behavior of Granite in Split Tension

2010 ◽  
Vol 44-47 ◽  
pp. 2368-2372
Author(s):  
Gang Chen ◽  
Yu Chun Kuang ◽  
Peng He ◽  
Ai Ming Xu

Tensile strength is one of the most important mechanical properties of granite. It is a key parameter for strength design, safety analysis of granite structures. In the present paper, experimental investigation on static and dynamic splitting tensile behavior of granite is carried out with Brazilian disc (BD) test. The incident wave of SHPB for the dynamic BD test was designed with pulse shaper. The results show that the dynamic tensile strength of granite is heightened with increasing strain rate.

2007 ◽  
Vol 353-358 ◽  
pp. 599-602
Author(s):  
Sung Rok Ha ◽  
Kyong Yop Rhee ◽  
H.H. Shin

It is well-known that the mechanical properties of nanocomposites are better than those of conventional composites. One of problems in fabricating nanocomposites is a dispersion of nanoparticles in the composites. In this study, the effect of MMT content on the tensile characteristics of trifunctional silane-treated MMT/epoxy nanocomposite was investigated. It was found that the tensile strength and the elastic modulus increased by over 24% and 83%, respectively, as the content of MMT increases from 2wt% to 10wt%. The improvement of tensile strength and modulus with increasing content of MMT occurs because the reinforcing effect of MMT becomes greater than the deteriorating effect due to the interfacial debonding between MMT and epoxy as the MMT content increases.


2018 ◽  
Vol 10 (1) ◽  
pp. 26-53
Author(s):  
Junzhou Duan ◽  
Yubin Lu ◽  
Shu Zhang ◽  
Xiquan Jiang

To comparatively study the tensile properties and fracture patterns of recycled aggregate concrete with various replacement percentages (i.e. 0%, 25%, 50%, 75%, and 100%) of recycled coarse aggregate, the dynamic direct tensile tests, splitting tests, and spalling tests of recycled aggregate concrete in the strain-rate range of 100–102 s−1 were carried out using large diameter (75 mm) split Hopkinson tensile bar and pressure bar. Test results show that for recycled aggregate concrete, the quasi-static direct tensile strength is more marvelous than its quasi-static splitting strength. When recycled coarse aggregate replacement percentage is 0%–75%, the replacement percentage impact minimally on the quasi-static tensile strength of recycled aggregate concrete. In dynamic tensile tests, there exists apparent difference between the dynamic direct tensile strength and dynamic splitting. The dynamic tensile strength of recycled aggregate concrete increases with the increase of average strain-rate in all three kinds of tests. The average strain-rate affects the damage form of recycled aggregate concrete, which indicates that the recycled aggregate concrete has obvious rate sensitivity. There shows no obvious regularity between the dynamic tensile strength and the recycled coarse aggregate replacement percentage. And the indirect tensile strength calculation method used in this article offers the theoretical basis for the engineering application of recycled aggregate concrete.


2004 ◽  
Vol 465-466 ◽  
pp. 361-366 ◽  
Author(s):  
Yuji Ogata ◽  
Woo-jin Jung ◽  
Shiro Kubota ◽  
Yuji Wada

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Fanlu Min ◽  
Zhanhu Yao ◽  
Teng Jiang

The dynamic characterization of concrete is fundamental to understand the material behavior in case of heavy earthquakes and dynamic events. The implementation of material constitutive law is of capital importance for the numerical simulation of the dynamic processes as those caused by earthquakes. Splitting tensile concrete specimens were tested at strain rates of 10−7 s−1to 10−4 s−1in an MTS material test machine. Results of tensile strength versus strain rate are presented and compared with compressive strength and existing models at similar strain rates. Dynamic increase factor versus strain rate curves for tensile strength were also evaluated and discussed. The same tensile data are compared with strength data using a thermodynamic model. Results of the tests show a significant strain rate sensitive behavior, exhibiting dynamic tensile strength increasing with strain rate. In the quasistatic strain rate regime, the existing models often underestimate the experimental results. The thermodynamic theory for the splitting tensile strength of concrete satisfactorily describes the experimental findings of strength as effect of strain rates.


Author(s):  
Jun Hua ◽  
Zhirong Duan ◽  
Chen Song ◽  
Qinlong Liu

In this paper, the mechanical properties, including elastic properties, deformation mechanism, dislocation formation and crack propagation of graphene/Cu (G/Cu) nanocomposite under uniaxial tension are studied by molecular dynamics (MD) method and the strain rate dependence is also investigated. Firstly, through the comparative analysis of tensile results of single crystal copper (Cu), single slice graphene/Cu (SSG/Cu) nanocomposite and double slice graphene/Cu (DSG/Cu) nanocomposite, it is found that the G/Cu nanocomposites have larger initial equivalent elastic modulus and tensile ultimate strength comparing with Cu and the more content of graphene, the greater the tensile strength of composites. Afterwards, by analyzing the tensile results of SSG/Cu nanocomposite under different strain rates, we find that the tensile ultimate strength of SSG/Cu nanocomposite increases with the increasing of strain rate gradually, but the initial equivalent elastic modulus basically remains unchanged.


2011 ◽  
Vol 181-182 ◽  
pp. 749-753
Author(s):  
Lv Tao Zhu ◽  
Bao Zhong Sun

In this study, tensile experiments of Twaron fiber tows under different strain rates (quasi-static:0.001s-1, dynamic: 800s-1~2400s-1) were carried out with MTS 810.23 materials tester and split Hopkinson tension bar (SHTB) respectively. The results showed that the mechanical properties of the Twaron fiber tows were sensitive to strain rate: the stiffness and failure stress of the fiber tows increased distinctly as the strain rate increased, while the failure strain decreased. From scanning electronic microscope (SEM) photographs of the fracture surface, it is indicated that the Twaron fiber tows failed in a more tough mode and the axial split will become more severe as the strain rate increases.


2018 ◽  
Vol 765 ◽  
pp. 54-59 ◽  
Author(s):  
Xiang Dong Chen ◽  
Xin Long Chang ◽  
You Hong Zhang ◽  
Bin Wang ◽  
Qing Zhang ◽  
...  

To study the low temperature effects of tensile mechanical properties on Hydroxyl-terminated polybutadiene (HTPB) propellant, a quasi-static mechanical experiment was conducted. The results show that tensile mechanical parameters are closely related to strain rate and low temperature. With the decrease of temperature and increase of strain rate, the modulus and tensile strength of HTPB propellant increase obviously. Based on the time-temperature equivalence principle (TTEP), the master curves of tensile strength and initial modulus for HTPB propellant were obtained, which can facilitate the structural integrity analysis of the propellant. The damage of propellant is matrix tearing and dewetting between the filled particles and matrix.


2021 ◽  
Author(s):  
Ramesh Chand ◽  
Vishal S Sharma ◽  
Trehan Rajeev

Abstract Polymer material based products in the engineering field are most widely produced by the multi jet printing (MJP). These products impart inherent benefits in manufacturing intricate contours and shapes at less additional expenses. This emphasizes the importance of studying the mechanical behavior of the manufactured parts, using polymeric materials in different orientations. In this investigation density, tensile behavior & hardness were studied for 3D-printed parts produced in four different orientations (A, B, C and D). It is found that for the best mechanical properties part should be fabricated using orientation ‘A’. Furthermore, for density and tensile strength part should not be fabricated using orientation ‘C’. Also in case of hardness part should not be fabricated in orientation ‘B’.


2006 ◽  
Vol 34 (2) ◽  
pp. 119-134 ◽  
Author(s):  
Syeda A. Hussain ◽  
Michelle S. Hoo Fatt

Abstract Tensile tests were conducted to obtain the deformation and failure characteristics of unfilled natural rubber (NR) and natural rubber with 25, 50, and 75 phr of N550 carbon black filler under quasistatic and dynamic loading conditions. The quasistatic tests were performed on an electromechanical INSTRON machine, while the dynamic test data were obtained from tensile impact experiments using a Charpy impact apparatus. In general, the modulus of the stress-extension ratio curves increases with increasing strain rate up to about 407, 367, 346, and 360 s−1 for unfilled, and 25, 50, and 75 phr for filled NR, respectively. Above these strain rates, the unfilled and filled natural rubber stress-extension ratio curves remained unchanged. The modulus increased with increasing strain rate because there was little time for stress relaxation. Above a critical strain rate, no change in modulus was observed because the time of the experiment was short compared to the lowest characteristic relaxation time of the material. Dynamic stress-extension ratio curves did not have the very sharp upturn at break, which is observed from strain-induced crystallization in natural rubber under quasistatic loading. Strain-induced crystallization appeared to be suppressed at high rates of loading. In fact, the highest dynamic tensile strength for the 25- and 50-phr carbon black-filled natural rubbers was smaller than those under quasistatic loading, while the highest dynamic tensile strength of the 75-phr carbon black-filled NR was greater than that in the static test. This indicated that high amounts of carbon black fillers will impede strain-induced crystallization in natural rubber.


2014 ◽  
Vol 788 ◽  
pp. 243-248 ◽  
Author(s):  
Bao Kang Gu ◽  
Da Tong Zhang

In this study, 5083 aluminum alloy plates with a thickness of 3mm are friction stir welded and the microstructure and mechanical properties of the joints were characterized. In particular, tensile behavior of the joints is examined at 77K. It is found that defect-free joints can be obtained under a tool rotational rate of 800rpm and a welding speed of 60mm/min. The friction stirring welds exhibit finer microstructure and higher hardness than that of the base material due to the grain refinement. The ultimate tensile strength (UTS) and elongation of the joints measured at 298K are 316MPa and 21.3%, which are nearly equal to those of the base material. With the tensile test temperature decreasing to 77K, UTS and elongation of both the base material and joints increase. Comparing with tensile testing at 298K, dimples on the fracture surface of the samples tested at 77K are more uniform in distribution. The improvement of the mechanical properties of specimens at low temperature is related to the inactivation of planar slip and the strengthening of strain hardening.


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