Mechanical properties of granite under real-time high temperature and three-dimensional stress

2020 ◽  
Vol 136 ◽  
pp. 104521
Author(s):  
Xiao Ma ◽  
Guiling Wang ◽  
Dawei Hu ◽  
Yanguang Liu ◽  
Hui Zhou ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Real Time ◽  
Three Dimensional

scholarly journals Influence of Real-Time Heating on Mechanical Behaviours of Rocks

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Bin Gu ◽  
Zhijun Wan ◽  
Yuan Zhang ◽  
Yangsheng Ma ◽  
Xiaodong Bernard Xu
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Real Time ◽  
Heating Temperature ◽  
Thermal Cracking ◽  
Effect Of Temperature ◽  
Rock Engineering ◽  
Mechanical Behaviours ◽  
Theoretical And Numerical Analysis ◽  
Rock Mechanical Properties

The rock mechanical properties under the effect of high temperature present a great significance on underground rock engineering. In this paper, the mechanical properties of sandstones, marbles, and granites under real-time heating were investigated with a servo-controlled compression apparatus. The results show that mechanical behaviours of all the three types of rocks are influenced by real-time heating to different degrees. Due to thermal cracking, the uniaxial compressive strengths decrease as the heating temperature rises from room temperature to 400°C. Above 400°C, the sandstone exhibits a significant increase in UCS because of the sintering reaction. The sintering enlarges the contact area and friction between crystal grains in the sandstone, which strengthens the bearing capacity. For marbles, the UCS continues to decrease from 400°C to 600°C due to thermal cracking. However, the carbonate in the marble begins to decompose after 600°C. The generated particles would fill the cracks in the marble and increase the strength. For granites, their UCS presents a sharp decline after 400°C because of thermal cracking. For all rock elastic modulus, they present a decreasing trend, and this indicates that the rock’s ability to resist deformation gradually weakens under the effect of temperature. In general, rock mechanical behaviours under real-time heating differ from those in normal situations, and use of the parameters presented here is important for underground rock engineering related to high temperature and can improve the precision in theoretical and numerical analysis.

Fabrication and Characterization of Porous TiB2 Ceramic with Three-Dimensional Interconnected Skeleton

2007 ◽  
Vol 336-338 ◽  
pp. 1076-1079
Author(s):  
Chang Qing Hong ◽  
Jie Cai Han ◽  
Xing Hong Zhang ◽  
He Xin Zhang
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Bending Strength ◽  
Three Dimensional ◽  
Pressureless Sintering ◽  
Neck Growth ◽  
Selective Heating ◽  
Fabrication And Characterization ◽  
Tib2 Particles

Porous TiB2 ceramics with a three-dimensional interconnected skeleton were fabricated by high temperature pressureless sintering from fine TiB2 powders. The microstructure of the porous TiB2 ceramic was characterized by the enhanced neck growth between the initially touching particles. This neck growth was ascribed to the selective heating of TiB2 particles with different dimension. The porous structure prepared by the high-temperature sintering exhibited higher bending strength and fracture toughness in the present experiment. The improved mechanical properties of the sintered composites were attributable to the enhanced neck growth by surface diffusion.

Vanillin-based thiol-ene systems as photoresins for optical 3D printing

2019 ◽  
Vol 26 (2) ◽  
pp. 402-408 ◽  
Author(s):  
Aukse Navaruckiene ◽  
Sigita Kasetaite ◽  
Jolita Ostrauskaite
Keyword(s):  
Mechanical Properties ◽  
Real Time ◽  
Design Methodology ◽  
Three Dimensional ◽  
Insoluble Fraction ◽  
Content Type ◽  
Three Dimensional Printing ◽  
First Time ◽  
Dimensional Printing ◽  
Kinetics Of

Purpose This study aims to present a design and investigation of novel vanillin-based thiol-ene photocurable systems as candidate materials for optical three-dimensional printing. Design/methodology/approach Two vanillin acrylates, vanillin dimethacrylate and vanillin diacrylate, were tested in thiol-ene photocurable systems with 1,3-benzenedithiol. The kinetics of photocross-linking was investigated by real-time photorheometry using two photoinitiators, diphenyl (2,4,6-trimethylbenzoyl)phosphine oxide or ethyl (2,4,6-trimethylbenzoyl)phenylphosphinate in different quantities. The dependencies of rheological properties of resins on the used vanillin derivative, photoinitiator, and the presence of a solvent, as well as structure, thermal and mechanical properties of the selected polymers were investigated. Findings The most rigid polymers were obtained from vanillin diacrylate-based resins without any solvent. The vanillin diacrylate-based polymer possessed higher values of cross-linking density, the yield of insoluble fraction, thermal stability and better mechanical properties in comparison to the vanillin dimethacrylate-based polymer. Originality/value The kinetics of photocross-linking of vanillin-based thiol-ene systems was investigated by real-time photorheometry for the first time. The designed novel photocurable systems based on vanillin acrylates and 1,3-benzenedithiol are promising renewable photoresins for optical three-dimensional printing on demand.

scholarly journals Study on Dynamic Mechanical Properties and Failure Mechanism of Sandstones under Real-Time High Temperature

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-19
Author(s):  
JiaZhi Zhang ◽  
Ming Li ◽  
Gang Lin ◽  
Lianying Zhang ◽  
Hao Yu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
High Temperature ◽  
Strain Rate ◽  
Real Time ◽  
Dynamic Mechanical Properties ◽  
Peak Strain ◽  
Dynamic Mechanical ◽  
Dynamic Compressive Strength

The research on dynamic mechanical properties of rocks under high temperature is the basis for safe and efficient implementation of deep coal mining and underground coal gasification engineering. In this paper, the split Hopkinson bar (SHPB) with real-time high-temperature function was adopted to systematically study dynamic mechanical properties of sandstones. The research showed that under the condition of a fixed temperature, with the increase of strain rate, the dynamic compressive strength and dynamic peak strain of sandstone increased gradually, and the variation of dynamic elastic modulus with strain rate was not obvious. With the increase of temperature, the dynamic compressive strength of sandstone increased first and then decreased, the dynamic peak strain increased gradually, and the dynamic elastic modulus decreased overall. The variation law of macroscopic failure mode and energy dissipation density with temperature was revealed, and the change mechanism was explained considering the influence of high temperature on the internal structure of sandstone. Based on the principle of component combination and the theory of micro-element strength distribution, the dynamic statistical damage constitutive model was established, and its parameters had certain physical significance. Compared with the experimental results, the established model can well describe the dynamic stress-strain relationship of sandstone under real-time high temperature.

scholarly journals Experimental Study of Strain Rockburst considering Temperature Effect: Status-of-the-Art and Prospect

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Lei Xu ◽  
Fengqiang Gong
Keyword(s):  
High Temperature ◽  
Real Time ◽  
Country Rock ◽  
Three Dimensional ◽  
Simulation Test ◽  
Dynamic Disturbance ◽  
True Triaxial ◽  
Strain Burst ◽  
Simulation Testing ◽  
Temperature Strain

In deep mining and excavation of tunnels with high geothermal, the surrounding rock is not only subjected to high ground stress but also subjected to high temperature. Temperature will change mechanical characteristics and energy storage capacity of rocks, as well as increase the destructiveness and randomness of rockburst. To reveal the mechanism of high-temperature strain burst in deep rock, the rockburst tests from uniaxial compression to three-dimensional compression were reviewed, and the research results of the minimum principal stress rapid unloading, true-triaxial loading with one free face, and dynamic disturbance triggered pre-heated granite rockburst simulation tests were focused on. According to the occurrence state of country rock for deep high-temperature and stress state in the whole process during excavation, six development directions for high-temperature strain rockburst simulation tests were proposed: (1) constructing the damage constitutive models of high-temperature rocks according to linear energy dissipation law; (2) developing the true triaxial rockburst simulation testing system accomplishing the function of “real-time high temperature + unloading + dynamic disturbance”; (3) considering the true triaxial rockburst simulation test after microwave irradiation; (4) developing the real-time high-temperature rockburst simulation testing device for large-size specimens and internal unloading; (5) focusing on the energy actuating mechanism for deep high-temperature rock failure via rockburst simulation tests; and (6) implementing the three-dimensional rockburst simulation test on the basis of deep in situ coring.

Lattice Imaging of Grain Boundaries in Ceramics

1977 ◽  
Vol 35 ◽  
pp. 114-115
Author(s):  
D. R. Clarke ◽  
G. Thomas
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Silicon Nitride ◽  
Grain Boundaries ◽  
High Temperature Strength ◽  
Current Interest ◽  
Lattice Imaging ◽  
Special Significance ◽  
Structural Applications ◽  
Refractory Ceramics

Grain boundaries have long held a special significance to ceramicists. In part, this has been because it has been impossible until now to actually observe the boundaries themselves. Just as important, however, is the fact that the grain boundaries and their environs have a determing influence on both the mechanisms by which powder compaction occurs during fabrication, and on the overall mechanical properties of the material. One area where the grain boundary plays a particularly important role is in the high temperature strength of hot-pressed ceramics. This is a subject of current interest as extensive efforts are being made to develop ceramics, such as silicon nitride alloys, for high temperature structural applications. In this presentation we describe how the techniques of lattice fringe imaging have made it possible to study the grain boundaries in a number of refractory ceramics, and illustrate some of the findings.

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