scholarly journals Experimental Investigation on the Mechanical Response of Coals to Uniaxial Compression and Low-Speed Dynamic Loading

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Jing-Xuan Zhou ◽  
Chuan-Jie Zhu ◽  
Xi-Miao Lu ◽  
Jie Ren ◽  
Rong-Jun Si ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Dynamic Loading ◽  
Mechanical Response ◽  
Fragment Size ◽  
Dynamic Compression ◽  
Dynamic Strain ◽  
Hysteresis Phenomenon ◽  
Gas Explosions ◽  
Static Mechanical ◽  
Static Mechanical Properties

The surrounding rock of roadways in underground coal mines will lose its stability or even collapse under gas explosions, especially roadways surrounded by coals. The dynamic mechanical properties of coals were tested in order to investigate the dynamic response of coals under gas explosions. The static mechanical properties of coals were also tested as comparison. It is found that the dynamic stress-strain curves showed no obvious pore compaction stage comparing with uniaxial loading. The dynamic compression strength and the elastic modulus are obviously larger than those obtained in the static mechanical properties test, and the dynamic strain shows an obvious hysteresis phenomenon. The ultimate strain and absorbed energy increased linearly with increase of the strain rate. With the increase of dynamic loading, the fragment size of coal cores decreased obviously. The results could provide a reference for the antiexplosion design of the coal roadway.

The Effects of SiO2/PEG Suspension on Mechanical Properties of Rigid Polyurethane Foams

2013 ◽  
Vol 815 ◽  
pp. 246-250 ◽  
Author(s):  
Xin Ya Feng ◽  
Shu Kui Li ◽  
Yan Wang ◽  
Ying Chun Wang ◽  
Jin Xu Liu
Keyword(s):  
Mechanical Properties ◽  
Silica Nanoparticles ◽  
Compression Strength ◽  
Dynamic Compression ◽  
Dynamic Mechanical Properties ◽  
Polyurethane Foams ◽  
Static Compression ◽  
Static Mechanical ◽  
Microstructure Density ◽  
Static Mechanical Properties

In order to improve the mechanical properties of the polyurethane foams, the silica nanoparticles were added into the foams in the form of SiO2/PEG suspension during the preparation process. The microstructure, density, static mechanical properties and dynamic mechanical properties of the foams were investigated. Microstructure analysis shows that the silica nanoparticles were uniformly dispersed in the foams, however when the amounts of SiO2/PEG suspension is more than 2.5 wt.%, cracks in the skelecton were observed in foams. With the increased SiO2/PEG suspension, the density, static compression strength and dynamic compression strength show an increasing tendency. When the SiO2/PEG suspension is 2.5 wt.%, the density of the foams increased 4.17 %, while the static compression strength increased 26 %. When the SiO2/PEG suspension is 10 wt.%, the density of the foams increased 16 %, while the dynamic compression strength increased 60.5 %. The corresponding mechanism was discussed in the paper.

scholarly journals Temperature-Dependent Creep Behavior and Quasi-Static Mechanical Properties of Heat-Treated Wood

Forests ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 968
Author(s):  
Dong Xing ◽  
Xinzhou Wang ◽  
Siqun Wang
Keyword(s):  
Mechanical Properties ◽  
Creep Behavior ◽  
Cell Walls ◽  
Treated Wood ◽  
Crosslinking Reaction ◽  
Depth Sensing ◽  
Temperature Dependent ◽  
Heat Treated ◽  
Static Mechanical ◽  
Static Mechanical Properties

In this paper, Berkovich depth-sensing indentation has been used to study the effects of the temperature-dependent quasi-static mechanical properties and creep deformation of heat-treated wood at temperatures from 20 °C to 180 °C. The characteristics of the load–depth curve, creep strain rate, creep compliance, and creep stress exponent of heat-treated wood are evaluated. The results showed that high temperature heat treatment improved the hardness of wood cell walls and reduced the creep rate of wood cell walls. This is mainly due to the improvement of the crystallinity of the cellulose, and the recondensation and crosslinking reaction of the lignocellulose structure. The Burgers model is well fitted to study the creep behavior of heat-treated wood cell walls under different temperatures.

Quasi-static mechanical properties of novel generalized Resch-pattern composite foldcores

2020 ◽  
pp. 095440622094000
Author(s):  
Antao Deng ◽  
Bin Ji ◽  
Xiang Zhou
Keyword(s):  
Mechanical Properties ◽  
Design Method ◽  
Absorption Capacity ◽  
Woven Fabrics ◽  
Geometric Design ◽  
Honeycomb Core ◽  
Reinforced Plastic ◽  
Static Mechanical ◽  
Laminate Thickness ◽  
Static Mechanical Properties

A new geometric design method for foldcores based on the generalized Resch patterns that allow face-to-face bonding interfaces between the core and the skins is proposed. Based on the geometric design method, a systematic numerical investigation on the quasi-static mechanical properties of the generalized Resch-based foldcores made of carbon fiber-reinforced plastic (CFRP) woven fabrics subjected to compression and shear loads is performed using the finite element method that is validated by experiments. The relationships between the mechanical properties and various geometric parameters as well as laminate thickness of the generalized Resch-based CFRP foldcores are revealed. Additionally, the mechanical properties of the generalized Resch-based CFRP foldcore are compared to those of the standard Resch-based, Miura-based foldcore, the honeycomb core, and the aluminum counterpart. It is found that the generalized Resch-based CFRP foldcore performs more stably than the honeycomb core under compression and has higher compressive and shear stiffnesses than the standard Resch-based and Miura-based foldcores and absorbs as nearly twice energy under compression as the Miura-based foldcore does. When compared with the aluminum counterpart, the CFRP model has higher weight-specific stiffness and strength but lower energy absorption capacity under shearing. The results presented in this paper can serve as the useful guideline for the design of the generalized Resch-based composite foldcore sandwich structures for various performance goals.

A Study on Estimation of S-N Curves for Structural Steels Based on their Static Mechanical Properties

2014 ◽  
Vol 891-892 ◽  
pp. 1639-1644 ◽  
Author(s):  
Kazutaka Mukoyama ◽  
Koushu Hanaki ◽  
Kenji Okada ◽  
Akiyoshi Sakaida ◽  
Atsushi Sugeta ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Evaluation Method ◽  
Materials Science ◽  
Estimation Method ◽  
Structural Steels ◽  
Metallic Materials ◽  
Fatigue Reliability ◽  
Regression Parameters ◽  
Static Mechanical ◽  
Static Mechanical Properties

The aim of this study is to develop a statistical estimation method of S-N curve for iron and structural steels by using their static mechanical properties. In this study, firstly, the S-N data for pure iron and structural steels were extracted from "Database on fatigue strength of Metallic Materials" published by the Society of Materials Science, Japan (JSMS) and S-N curve regression model was applied based on the JSMS standard, "Standard Evaluation Method of Fatigue Reliability for Metallic Materials -Standard Regression Method of S-N Curve-". Secondly, correlations between regression parameters and static mechanical properties were investigated. As a result, the relationship between the regression parameters and static mechanical properties (e.g. fatigue limit E and static tensile strength σB) showed strong correlations, respectively. Using these correlations, it is revealed that S-N curve for iron and structural steels can be predicted easily from the static mechanical properties.

Simulation studies to analyze the static mechanical properties of helical Savonius vertical axis wind turbine blade

2020 ◽  
Vol 33 ◽  
pp. 3737-3745
Author(s):  
S. Seralathan ◽  
Ch. Pavan Veera Sai Ganesh ◽  
Bhanu Prakash Reddy Venganna ◽  
N. Sai Srinivas ◽  
B. Lokesh Chowdary ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Wind Turbine ◽  
Turbine Blade ◽  
Vertical Axis ◽  
Wind Turbine Blade ◽  
Simulation Studies ◽  
Vertical Axis Wind Turbine ◽  
Static Mechanical ◽  
Static Mechanical Properties
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