scholarly journals EXPERIMENTAL STUDIES OF THE GLUED WOOD STRENGTH AND DEFORMATION PROPERTIES UNDER THE HARD TEST MODE

2020 ◽  
Vol 2 (3) ◽  
pp. 130-135
Author(s):  
S.S. Gomon ◽  
L.M. Pilipaka
Keyword(s):  
Experimental Studies ◽  
Test Mode ◽  
Deformation Properties ◽  
Strength And Deformation ◽  
Wood Strength

Experimental Studies on Mechanical Properties of Rock Joints under Dynamic Loading

2006 ◽  
Vol 326-328 ◽  
pp. 1709-1712 ◽  
Author(s):  
Hai Bo Li ◽  
Hai Peng Feng ◽  
Bo Liu ◽  
Jun Ru Li
Keyword(s):  
Mechanical Properties ◽  
Normal Stress ◽  
Rock Joint ◽  
Experimental Studies ◽  
Shear Stiffness ◽  
Shear Velocity ◽  
Rock Joints ◽  
Normal Stresses ◽  
Deformation Properties ◽  
Strength And Deformation

In order to study the strength and deformation properties of rock joint under different shear velocities, normal stresses and undulation angles, series testes are conducted by a RMT-150C testing machines with artificial concrete rock joint samples in the present paper. Base on the experimental results, it can be found that the peak shear strengths decrease with the increment of shear velocity, and the decreasing rates tend to decrease with the increasing shear velocity. The shear strength of rock joints increase with the increasing undulation angles, and linearly increase with the increment of normal stress. It is also indicated that the shear stiffness increase with the increasing normal stress, undulation angle as well as the shear velocity with a decreasing tendency.

scholarly journals Modern testing machines for investigation of wood and timber-based composite materials

2021 ◽  
pp. 73-80
Author(s):  
С.С. Гомон ◽  
В.О. Савчук ◽  
Ю.А. Мельник ◽  
О.В. Верешко
Keyword(s):  
Composite Materials ◽  
Testing Machine ◽  
Measuring Instruments ◽  
Strain Diagram ◽  
Timber Species ◽  
Recording Device ◽  
Stress Strain ◽  
Test Mode ◽  
Deformation Properties ◽  
Strength And Deformation

A detailed analysis of test machines and presses operating in both soft (increasing loads) and hard test mode (displacement increase) has been performed. The results of tests of deciduous, coniferous and tropical timber species on modern test machines of foreign production under a strict test regime were analyzed. The results of tests of timber and concrete on advanced presses of old production with the help of additional equipment are also given and analyzed. With the help of such equipment it is possible to build a "stress-strain" diagram completely on the ascending branch and partially on the descending branch. And also allows you to more widely establish the strength and deformation properties of concrete and timber. It was found that the influence of age on the main strength and deformation parameters has not been studied. In recent decades, testing machines and presses have begun to appear, which allow to investigate these or those materials from the beginning of loading and to its full destruction. That is, to analyze the work of different materials (metal, timber, concrete, etc.) on the ascending and descending branches, and in particular in the so-called supercritical stage of work. At the end of the 20th century, scientists developed electromechanical and servo-hydraulic universal testing machines, which make it possible to test samples from the beginning of loading until complete destruction (rigid test mode for incremental displacements), while fixing all the necessary strength and deformation indicators on the ascending and descending branches of the diagram "stress - strain", setting the necessary modes and loading speeds. Measuring instruments determine the forces and deformations at different stages of testing and transmit the measurement results to the recording device or means of information accumulation. The characteristics of modern testing machines, in particular electromechanical and servo-hydraulic, are given: WDW (Time Group Inc.), INSTRON (USA), REM (Russia), LFM (Switzerland). The possibilities of the STM-100 servo-hydraulic testing machine for the study of timber and composite materials based on it are described in detail..

scholarly journals STRUCTURAL DAMAGE ANALYSIS

2021 ◽  
Vol 30 (1) ◽  
pp. 12-19
Author(s):  
G. Kushnareva ◽  
◽  
N. Ismailova ◽  
I. Radchenko ◽  
T. Rabocha ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Bearing Capacity ◽  
Experimental Studies ◽  
Irreversible Processes ◽  
Material Consumption ◽  
Relative Load ◽  
Deformation Properties ◽  
Strength And Deformation ◽  
Accumulation Of Damage ◽  
Wooden Structures

The ability of materials to retain the required set of properties under the action of operational loads on the structure is determined by the structural changes that occur under such loads. From the first days of operation, under the influence of force factors, the environment and time, the strength and deformation properties of structures of buildings and structures change. The solution to the main task of construction science - reducing material consumption in construction, is inextricably linked with the need for constant study and refinement of the strength and deformation characteristics of building materials and structures, as well as a change in their bearing capacity over time and an assessment of the working capacity (resource) reserve when setting an external power load. Based on the fundamental position that under the action of a load, a deformation process occurs in the construction material, which is accompanied by irreversible processes of their appearance, development and accumulation of damage to the structure of the material, and, as a result, leads to destruction, we come to the conclusion that it is necessary to carefully study the strength of wooden designs taking into account this phenomenon. There is a need to comprehensively study the issues of damage accumulation in wooden structures under the action of loads and the related processes of changing the cross-sectional area and bearing capacity, to use the research results when calculating structures. This makes it possible to reduce material consumption and make the sections of wooden structures more economical and avoid excessive safety margins. Therefore, an important manifestation is the fixation of cracks and internal interfaces, which allows one to quantify the integral damage of the structure material to predict their safe functioning. The authors considered analytical dependences for the description of disseminated injuries that follow from physical considerations or are constructed from some mechanical models of the process of long-term damage. Three main types of models have been identified: force, deformation and energy. Experimental studies of normal stress diagrams make it possible to visually record the formation of folds in the compressed zone, as well as calculate the value of the instantaneous elastic and viscoelastic components of total deformation. A measure of the accumulation of damage in a material is damage. In this work, the damage was calculated based on the known specific parameters of the material: deflections, relative deformations and changes in the number of acoustic emission signals. The graphs of the dependence of damage on the load were built: - on the development of deflections; - on the development of fibrous deformations; - on the development of deflections and acoustic emission (relative load); - on the development of fibrous deformations (relative load); This scientific work is a logical continuation of previous studies of damage to wooden structures. The article presents the results of experimental studies of the strength, deformability of wooden beams under the influence of a static load. The direction of improving the methodology for designing wooden structures and determining the residual resource has not been reflected in the technical literature. Therefore, it is necessary to conduct a comprehensive study of them.

The mechanical behavior of the Kettle Point oil shale

1986 ◽  
Vol 23 (1) ◽  
pp. 87-93 ◽  
Author(s):  
Maurice B. Dusseault ◽  
Matthias Loftsson ◽  
David Russell
Keyword(s):  
Oil Shale ◽  
Clay Content ◽  
Organic Content ◽  
Point Load ◽  
Brazilian Test ◽  
Point Load Strength ◽  
Triaxial Strength ◽  
Deformation Properties ◽  
Strength And Deformation ◽  
Oil Shales

Samples of eastern black shale (Kettle Point oil shales, Ontario) were subjected to extensive mineralogical and geomechanical tests. We prove that the mineralogy, as measured by the ratio of quartz to illite, controls strength and deformation properties, and the organic material plays no significant role. The reason is that increasing clay content dilutes the rigid quartz–quartz grain contacts that are responsible for the high strengths and stiff behavior. Tests of temperature effects on point load strength of another low organic content oil shale confirm that organic matter is not important to mechanical properties in matrix-supported shales. Key words: shale, mineralogy, Brazilian test, triaxial strength, organic content, slake durability, thermogravimetry.

Experimental Studies of Fiber-Reinforced Concrete under Axial Tension

2021 ◽  
Vol 1038 ◽  
pp. 323-329
Author(s):  
Zlata Holovata ◽  
Daria Kirichenko ◽  
Irina Korneeva ◽  
Stepan Neutov ◽  
Marina Vyhnanets
Keyword(s):  
Reinforced Concrete ◽  
Experimental Studies ◽  
Fiber Reinforced Concrete ◽  
Load Application ◽  
Fiber Reinforced ◽  
Large Aggregate ◽  
Second Stage ◽  
Axial Tension ◽  
Deformation Properties ◽  
Fiber Concrete

The design of a stand for testing concrete and fiber-reinforced concrete specimens-"eight" in tension, which provides axial load application and minimizes the effect of stress concentration at the ends of the specimen. The design of the stand is such that the distance between the axis of load application and the central hinge is 108 cm, and between this hinge and the axis of the test specimen is 21 cm, as a result of which the load transferred to the specimen is 5.143 times greater than the applied one. At the first stage of testing, it was found that the optimal characteristics of the fiber-concrete mixture is a matrix with a large aggregate ≤ 10 mm with 1.0% fiber reinforcement. At the second stage, the ultimate strength of fiber-reinforced concrete for axial tension was determined - 1.28 MPa when reinforced with wave fiber and 1.37 MPa when reinforced with anchor fiber, which amounted to 4.1% and 4.4% of compressive strength, respectively. It was also found that concrete reinforced with anchor fiber has higher deformation properties than concrete reinforced with wave fiber.

scholarly journals Effect of carbon nanotubes on the properties of pmb and asphalt concrete

Vestnik MGSU ◽  
2015 ◽  
pp. 110-119 ◽  
Author(s):  
Svetlana Yur’evna Shekhovtsova ◽  
Marina Alekseevna Vysotskaya
Keyword(s):  
Asphalt Concrete ◽  
Water Resistance ◽  
Materials Science ◽  
Crosslinking Agent ◽  
Modern World ◽  
Progressive Development ◽  
Concrete Mixtures ◽  
Deformation Properties ◽  
Strength And Deformation ◽  
Modified Binder

In the modern world nanotechnologies are an integral part of successful and progressive development of all the areas of activity. Materials science is not an exception. The authors studied the method of nanomodification and its influence on the performance properties of polymer-modified binder (PMB) and asphalt concrete, produced on their basis. It is established that nanomodified PMB are less susceptible to aging, which is a consequence of the processes of peptization of asphalt-resin complexes (ARC) in the structure of the modified binder and the crosslinking with the polymer matrix. It is revealed that nanotubes (SWCN or MWCN) used as a modifier, act as crosslinking agent and the inhibitor of the aging process in a PMB. The influence of nanomodified PMB on strength and deformation properties of asphalt concrete is investigated. It was found out that the use of modified binder in the asphalt concrete mixtures enhances the water resistance of asphalt concrete, heat resistance and shear-resistance.

The strength and deformation properties of vitreous silica

1973 ◽  
Vol 30 (6) ◽  
pp. 379-382 ◽  
Author(s):  
V. M. Gulaev ◽  
K. I. Ryabtsev ◽  
V. S. Bakunov ◽  
D. N. Poluboyarinov ◽  
F. Ya. Borodai ◽  
...  
Keyword(s):  
Vitreous Silica ◽  
Deformation Properties ◽  
Strength And Deformation
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