The Effect of Small Additions of Carbon Nanotubes on the Mechanical Properties of Epoxy Polymers under Static and Dynamic Loads

2018 ◽  
Vol 63 (1) ◽  
pp. 32-40 ◽  
Author(s):  
A. E. Tarasov ◽  
E. R. Badamshina ◽  
D. V. Anokhin ◽  
S. V. Razorenov ◽  
G. S. Vakorina
2014 ◽  
Vol 1061-1062 ◽  
pp. 748-750
Author(s):  
Heng Chen ◽  
Ke Sheng Ma

For socked and non-socketed piles in the different mechanical behavior under static and dynamic loads, the paper use ABAQUS to model, simulate the pile , the soil interlayer thickness between the bottom of the pile and bedrock are 2m, 4m under vertical load and Earthquake, cushion cap, pile and pile soil stress situation found non-socketed piles when the soil interlayer thickness within a certain range, the composite pile small subside under dynamic, static loads, the non-socketed piles can better take advantage of the pile soil has a good seismic performance in the earthquake.


2020 ◽  
Vol 27 (10) ◽  
pp. 2945-2958
Author(s):  
Peng Xiao ◽  
Di-yuan Li ◽  
Guo-yan Zhao ◽  
Quan-qi Zhu ◽  
Huan-xin Liu ◽  
...  

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Enlai Zhao ◽  
Enyuan Wang ◽  
Zesheng Zang ◽  
Xiaojun Feng ◽  
Rongxi Shen

The complex mechanical environment of deep coal and rock masses leads to obvious changes on their dynamic mechanical properties. However, there are few reports on the dynamic mechanical properties of rocks under the combined action of medium temperature (normal temperature ∼100°C) and static and dynamic loads. In this paper, a dynamic load and temperature combined action Hopkinson pressure bar experimental system is used to experimentally study the impact type of a fine sandstone under temperature conditions of 18°C, 40°C, 60°C, 80°C, and 100°C, an axial static load of 3 MPa, a gas chamber pressure of 0.06 MPa, and a constant temperature time of 4 h. The dynamic characteristics of the change law of the fine sandstone and the energy dissipation characteristics of the load process are analyzed, and the characteristic law of the fine sandstone surface response is analyzed using digital image correlation technology. Our results indicate the following. (1) Under conditions in which the other experimental conditions remain unchanged, the dynamic stress-strain of the fine sandstone presents a bimodal shape with a “rebound” phenomenon. Increasing temperature causes the peak strength of the fine sandstone to increase; however, the relative strength can increase or decrease. The relative increase in the strength is 1.14 MPa (°C) when the temperature increases from 40°C to 60°C, 0.15 MPa (°C) when the temperature increases from 60°C to 80°C, and 0.62 MPa (°C) when the temperature increases from 80°C to 100°C. (2) The digital image correlation results show that, under the action of a dynamic load stress wave, the fine sandstone experiences a displacement vector change on the sample surface; furthermore, under the combined action of the temperature and dynamic and static loads, the fine sandstone experiences macroscopic shear failure. The surface strain in the propagation direction of the stress wave is obviously higher and can even reach values of more than 10 times that of the strain in other directions. (3) From the perspective of energy dissipation, the incident energy, reflected energy, and dissipated energy of the fine sandstone under an impact load have the same change law. After being affected by a dynamic load, the energy rapidly increases to a certain value and then remains relatively stable. The transmitted energy is relatively small and can be approximated as a horizontal line. As the temperature increases, the incident energy, reflected energy, and dissipated energy tend to first decrease and then increase, and most of the incident energy in the fine sandstone is dissipated in the form of reflected waves.


2021 ◽  
Vol 11 (19) ◽  
pp. 8973
Author(s):  
Kun Zhong ◽  
Wusheng Zhao ◽  
Changkun Qin ◽  
Hou Gao ◽  
Weizhong Chen

Roof rocks in coal mines are subjected to the combination of in situ stresses and dynamic stresses induced by mining activities. Understanding the mechanical properties of roof rocks under static and dynamic loads at medium strain rates is of great significance to revealing the mechanism of rock bursts. In this study, we employ the digital image correlation (DIC) technique to investigate the energy concentration and dissipation behaviors, failure mode, and deformation characteristics of roof rocks under combined static and dynamic loads. Our results show that both the static pre-stress and dynamic loading rate have significant effects on the uniaxial compressive strength of rock specimens. From the energy principle, when the static pre-stress is the same, both elastic strain energy density and dissipated energy density increase with increasing dynamic loading rate. The hazard of rock bursts increases with decreasing static pre-stress and increasing dynamic loading rate. At higher dynamic loading rates, more cracks are generated, and the failure becomes more violent. The crack initiation, propagation and coalescence processes are identified, and the failure mode is closely related to the evolution of the global principal strain field of the rock specimens.


2022 ◽  
Vol 58 (4) ◽  
pp. 222-237
Author(s):  
Costel Iulian Mocanu ◽  
Alin Pohilca ◽  
Liviu Moise ◽  
Daniela Ioana Tudose

Glass reinforced plastic, so called GRP, is a composite material made of glass strands called fibbers woven together to create a flexible fabric. GRP is a lightweight material with many and diverse applications ranging from the manufacture of reservoirs for different liquids to the manufacture of boats, yachts, chairs and even children playground furniture. The behaviour of this material under static and dynamic loads is still raising interest from the scientific community and a large number of researchers. This continued interest is due to the material versatility for different applications depending on its manufacture process that has a significant weigh-in in the material mechanical properties. These resulting mechanical properties need to be carefully analysed and benchmarked prior to using the obtained material in commercial applications. The scope of this research study is to analyse the behaviour of glass reinforced plastic plate panel with reinforcements on one and two directions under static and dynamic loads employing both experimental and numerical methods for results validation. The methods used in this research study for the dynamic loads can also be applied successfully to other composite materials. Additionally, the stress plots have been analysed in iteration in order to ensure the most optimal reinforcement pattern.


Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
Jinzheng Bai ◽  
Linming Dou ◽  
Piotr Małkowski ◽  
Jiazhuo Li ◽  
Kunyou Zhou ◽  
...  

This research is aimed at investigating the influence of the coal height ratio on the mechanical properties and damage behavior of rock-coal-rock combined samples (RCRCS) under coupled static and dynamic loads. For this purpose, a uniaxial cyclic dynamic loading experiment with four different coal height ratios of RCRCS was conducted. Mechanical properties, failure modes, and wave velocity evolution of RCRCS were analyzed; the process of rock burst under coupled static and dynamic loads in rock-coal-rock combined structure was discussed. The following research results are obtained. (1) The peak strength of RCRCS under static and dynamic load decreases with the increasing coal height ratio as an inverse proportional function. (2) The loading and unloading modulus remains consistent for the same levels of dynamic load; the coal height ratio of 40% may be the limit for the stable value of modulus. (3) The increase of the coal height in RCRCS leads to a gradual increase of the energy release rate; the cracks develop preferentially in coal and then extend to rock sample. The distribution of AE events and damage is consistent with the distribution of passive wave velocity. The research results provide important scientific bases for the guidance of early warning of rock burst.


Author(s):  
Çağrı Oruç ◽  
Okan Özdemir

Control arms are subjected to static and dynamic loads in car during their lifetime. Recent increases in loads in which control arms are subjected, are not complying with the low-weight design targets expected by auto makers. In this study, buckling behavior of control arms which have been produced with Si particle reinforced aluminum based metal composite material have been investigated and compared with the performance of control arms that are produced with standard aluminum alloy. The results revealed that mechanical properties of control arm housings with 10% Sip MMC material are lower than standard 6110 alloy due to different process parameters. Elasticity of modulus of control arm housings with 10% Sip MMC material are approximately 7% higher than standard aluminum alloys. Buckling results of control arms with 10% Sip MMC material are around 25% lower that control arms with standard 6110 alloy. Also, a second darker phase was found in the microstructure.


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